We got the basics of this in the first year of university Physics classes, then revisited it two years later to solve the full set of field equations for both ideal and real materials, and then measure the difference in the lab to get the right values in the model for the real materials and see the affect of mechanical design choices. The hardest part, by far, was summing the effects of all the fields in the disc and the topology (shape) of the induced currents. We also had to allow for the thermodynamics. A factor in the size and design of the disc is to dissipate heat, particularly to minimize peak local heating during high loads, and to have consistent behavior during the full range of environmental conditions. Aluminum is chosen for the disc because it has a good balance between conductivity and heat transfer while also minimizing angular inertia. Iron alloys could not be used because they could be magnetized (though we did not consider austenitic stainless steels). A copper alloy could work, but the disc mechanical design would need to be very different, with affects that would ripple through to the rest of the meter design.
Out of passing interest... eons ago, a friend lived in a large apartment complex. All the electric meters were on on a wall in the laundry room... there must have been 50 or more. He was doing laundry one day, & out of mere curiosity found his meter & noticed it rotating quite fast... then noted it speeding/slowing in time various laundry machines cycling on/off! Cheesed him off... but to be sure he ran & turned off his main breaker, & returned to find the same! He called & reported to his DWP; and they were there seemingly within minutes. It seems the landlord had jumpers behind that wall & rotated the laundry and common areas to different meters on a regular basis. He said it turned into a colossal legal S storm that lasted about a year.
I had a friend in a similar situation. Everything in his apartment was turned off, but the meter was still turning. So, he pulled his main fuse and put it in a drawer and left for a weeks vacation. It turned out that they ran the emergency lighting off his circuit, and since they couldn't find his main fuse holder, they had to rewire the emergency lighting elsewhere. They were not happy, but couldn't do much about it.
@@johnhaller5851 that's surely illegal, emergency lightning should be connected to a separate source, not to an individual apartment's meter board/meter.
I think the grid pattern of divots in the rotor is intended to make the rotor acceptably flat. When you stamp sheet metal, it often won't come out flat if you just smash it between two flat dies. The blank was almost flat to begin with, so the tiny amount it moves during stamping isn't enough to overcome the metal's elastic limit. When the press opens, the stamping springs back to it's original almost-but-not-quite flat shape. But if you make little divots everywhere, you stretch the metal much more. By exceeding the metal's elastic limit, you convince it to take on the shape of the flat dies.
Thanks, I always thought it was something like that, as I've only ever seen the pattern on folded metal parts that required a reasonable amount of precision, like a sheet of mild steel inside a printer with posts for mounting gears and motors etc.
@@soupisgoodfood42 Yep. You used to see this pattern all the time on chassis components in camera and electronic gear that required a modicum of precision. I've seen it in movie cameras, cassette recorders, VCRs and so forth. Anymore you don't see it so much, because so many consumer applications have replaced precision mechanicals (expensive) with electronics (inexpensive and usually perform better). A printer is one of the few places where a consumer device still requires high precision.
woah!!! that's a really cool and simple way to solve a complicated problem! Do u know why most utility companies chose to go with digital readers now days? there was alot of backlash in my city about it because it supposedly gave the electric companies too much control?
@@fitingsthdown The primary reason would be cost, particularly for the components to read the meter remotely since that's a lot easier to do with digital technology. If you don't need remote reading the cost differential is a lot less (and might actually be negative), but sending a person around to look at each meter and record the current value on it is quite expensive when you have millions of meters that need to be read each month!
You have to remember that V x I x COS(theta) on the disc creates a TORQUE, not an RPM. That means once the friction is overcome, it would go faster and faster. Those permanent magnets provide a drag proportional to the speed of the disc. Without the drag magnets it just won't record watt-hours. When you add drag proportional to speed, and TORQUE proportional to Watts, you get Watt-Hour.
The drag is from "eddy current braking", which is responsible for the neat effect of dropping a strong magnet through a copper pipe ( th-cam.com/video/lDIGFF1xfPM/w-d-xo.html ). Side story: We had an interactive TV exercycle that drove an electromagnet that was next to an aluminum disk which was spun by the bicycle pedals. After a couple minutes of peddling, I wondered where all the energy was going. My curiosity was quicker than my smarts as I reached down to touch the disk. WOW! that thing was hot!
@@atexnik The voltage induced in the disc by the rotation of the disc in the magnetic field from the permanent magnets will be proportional to the rotational velocity of the disc (Faraday's law). This voltage will cause a current to flow in the disc that is proportional to the voltage (Ohm's law). This current will give rise to a torque that is proportional to the current and hence proportional to the rotational velocity of the disc. To continue beyond your question: This torque opposes the torque caused by V I Cos(Theta), the power consumed by the customer. For any given power consumption, the disc will settle at a rotational velocity where the torque from the power consumed by the customer is matched by the torque from the drag effect (because in that situation there is no net torque to accelerate or decelerate the disc). Hence the rotational velocity of the disc is proportional to the power consumed by the customer. The scale factor for the drag torque effect could be chosen so that the bearing and gearing friction is not a problem for low consumed power, and disc rotational speed is not a problem for high consumed power. These requirements conflict, so a compromise would be chosen in practice.
Years ago I had a bundle of wires inside a conduit and needed to figure out which of the 20 or so wires was connected to a particular branch circuit. I made sure every appliance was turned off, then connected a hair dryer on high to the branch circuit I was trying to identify. I then held a 1" x 3/4" neodymium magnet close to the wire bundle and spread the wires apart. It was very easy to identify the correct wire, the magnet was vibrating in my hand just like you showed in the video. A very useful method.
@@ZaneDaMagicPufferDragon Also works great identifying DC circuits. The wire will be pulled toward the magnet or pushed away depending on the magnet's orientation.
Cody from "Cody's Lab" had a small piece of magnet inserted into the skin, with that he could sense magnetic flux near it, like high current in a wire. Basically enabling a 6:th sense.
@@Paxmax I used to have a magnet like that too. I could feel sufficently strong magnetic flux (removing stir bars in the lab was also a fun party trick). I could really feel it when I was MIG welding. No pain with that, but it was the only times I would have my hand around 50+ A. I could also feel the flux around motors for a good 6" inches.
I think most of them reached their topmost point of advancement before taken down by digital stuff. Mechanical stuff of the past decades are always fascinating as they're bot reliable and performing good.
That style of plug in meter base can actually have the meter installed rotated 90deg, when in this arrangement none of the electrical connections are made and the meter is just acting as a cover for the bare terminals. This function is used when the electricity company wants to disconnect supply from a property without removing the meter from site as the meter is tied to the address. It is used mainly when disconnecting people for non payment or when a rental property is unoccupied for an extended period and has the advantage that the meter can have the seals fitted to prevent the customer from tampering with the disconnection. Source - former metering tech
We had a mechanical meter for a little while with a solar system. The retailer's systems eventually managed to cope with negative electricity usage each month, although eventually they fitted a non smart digitial meter that only lasted a few months before they replaced it again with one with a radio. It was pretty fun to watch the mechanical meter on a bright day when someone was welding as it would be spinning moderately fast backwards, before spinning very fast forwards for a few seconds, then going back to its usual spinning backwards :).
Actually here... first I had a digital meter which was not able to run backwards for the solar-panels so the installation was changed into a mechanical meter for years but then needed to be replaced with a 'Smart meter'. Well, yes, smart for the company, not for me. Normally I use about the same as the solarpanels provide, thus the old meter was just standing still for days and sometimes going a bit forward in the night, going back during daytime. Well, that is not possible anymore and much more measured energy now with the Smart meter...
@@elvinhaak nowadays they put 2 meters, but it doesn't matter, because they buy energy from you cheaper than they sell, no matter what. so you best not put the energy back when you don't need. put it into cryptocurrency, lol.
Funny. Most, if not all, mechanical electricity meters in my country have a built-in power flow backstop. If you feed power to the grid, the discs rotates backwards, but whell with digits does not
Hi Dave .. you did an excellent job explaining all this. Back in the 80s I spent over 10yrs working for a power company calibrating single & 3 phase meters and troubleshooting meter problems. People used to drill holes through the case and poke a bit of wire into the brake magnet (and of course remove it before the meter reader was due) and play around trying to slow them down with an external magnet. Our own experiments with external magnets showed that you are just as likely to speed the meter up ... This particular meter like most later ones has magnetic suspension usng the two repulsion magnets at the bottom combined with an upper and lower centering guide needle .. We typically tested meter calibration at both unity and .5 PF (Cos 60), the power factor adjust is the 2 copper vanes on the rotatable shaft. Full load adj usually involves movement of the brake magnet but this later L&G appears to be using a different form of brake magnet adjustment
Hi, I do have a similar job in the "Zählerwerkstatt" (so called in german) as you in the late 70s. It was the time where I get my first programmable calculator (a TI59).So I wrote programs to help us calibrating the meters. It is funny to look back to those times... I'm living in northern germany. I wish you a happy new year and take care.
The trick is to get an old low voltage/high current filament and wire the secondary across the meter, one lead on an AC outlet the other on the mains. Then put a Variac on the primary of the filament transformer. as you raise the Variac voltage the disc slows down and starts the disc running backward. This is of course purely theoretical and is for educational purposes only.
drilling a hole from the neighbor exactly to the correct place and putting a wood branch did the trick of slowing down the disc for me. But yours are better.
Faraday's law: The induced emf in the disk and the induced eddy current in the disk is proportional to the flux rate of change. The torque on the disk is proportional to the eddy current times the instantaneous magnetic field. When voltage is maximum (positive or negative), it provides a background magnetic field centered on the coil assembly so that the offset eddy current induced by the rapidly changing current is attracted or repelled. When the current is maximum (positive or negative), it provides a background magnetic field offset from the center that attracts or repels the centered eddy current generated by the quickly changing voltage. All four torques are in the same direction. Torque provides angular acceleration except that the permanent magnets' eddy currents provide opposite torque proportional to disk speed. Together the disk's speed is in equilibrium at some speed proportional to the IV's torque... proportional to power. The counter integrates the disk's speed (power) wrt time to yield Watt-hours. Very sharp spikes are filtered out by the disk's inertia.
This was really fascinating. I always wondered how those old meters work. Thanks Dave for the great explanation. Please do more of those educational videos.
The dimples on the disc can be scanned with a photo electric cell during calibration. It speeds up the testing process when a line of meters is on the test bench. The readers are mounted above the meter and read the 10 dimples as the reflect the light back from the opto LED in the photocel. So for each revolution of the disc, 10 pulses are 'generated'. The Landis & Gyr CL 147 has similar patterns on the disc, which was a predecessor of this meter, made in the UK.
Decades ago as a young pre-teen technology enthusiast I got one of these kWh meters from my grandmother's house renovation and of course took it apart. I don't think I then understood how it works at all, it was just an interesting gadget to dismantle :) I vaguely remember wondering how the simple metal disc could spin when there is no contact with anything but the counter.
Oh I just remembered that it had a kind of U-shaped magnet almost like in the cartoons, except the ends were bent to almost close the shape to an O, but then again bent outward to become parallel to the long sides so that the gap in between was just large enough to allow the disc to spin freely in between. Or maybe if you imagine the Greek letter omega with just the horizontal "feet" clipped off :) I had that magnet a long time in my gadget collection as a fun thing to play with from time to time.
Had a funny one for you. Had an analogue meter on a remote site that was permanently shut down; site uses like $150/month in power. After the site was shut-down, 3 months went by, utility company swapped the utility meter, and then another billing cycle went by and they billed us $15,000 because they thought the meter rolled over. What a great day at the office. 🤙
It feels nice when you compliment this precision product of my home country, Switzerland. The company name is spoken like „Landes and Ger“ as the „y“ is spoken like a „e“ in English or an short „i“ in Alemannic. Even in my current flat there are still Landis & Gyr devices at work. Indestructible and very reliable.
I was an electrician in the states for many years and one of my hobbies was collecting vintage A-base watthour meters. I have meters going back to the early 1900's and a few more modern ones. I made table lamps out of a few of the modern ones.. These meters are fascinating and beautiful in their simplicity. A voltage coil and an amperage coil and a magnet.
3 Phase meters are interesting too, they just have 3 of those disks on the same spindle. Being connected on one spindle it will measure true resulting power. These measure true power regeardless of the noise on the powerlines due to switching powersupplies, led lamps and other odd consumers. Digital meters need all kinds of clever engineering to get the same accurate result. Those mechanical meters do not need any of it and are just accurate, even 50 year old ones.
Last I saw one of these for three phase it still only had one disk, I would assume that it have some mechanics to transmitt and if needed add together the three inputa
Thanks for the info. I was just wondering how accurate these were with large amounts of harmonic distortion in the load. I have one of these from the 40s mounted on a panel that I use to track hydroponics lighting energy usage. It's almost completely identical to this except it has dial indicators, but the internals are essentially the same.
The earliest ones as well as many European ones have multiple disks, but many North American models have two or three stators around the edge of the disk. The single disk meters actually have laminated disks to minimize interference between the stators.
It is truly amazing how accurate these meters can measure, not to forget how little they cost. It is like the predecessor of hard drives in these regards.
I obtained one, left over from a power company customer, and built it into a benchtop power meter. I discovered that it only works well when mounted with the rotating disk axis close to vertical. It has very little friction in that orientation, but much more friction when tilted. When rotated 90 degrees from vertical, it didn't move at all.,
If you want to see real insanity, look at marine chronometers from the 1700s... Mechanical timekeeping good to 1 second in 100 days for finding longitude at sea, when modern all mechanical watches (Even the ones with the certified marine chronometer tag) are only guaranteed good to a few seconds a day. At the time they were the most complex devices ever manufactured - temperature compensation was a huge component of making them keep good time.
The pointer registers have the advantage of consistent friction, while all cyclometer registers have a weight to help push the last dial from 9 to 0, as multiple drums need to advance in the same interval.
The dials are all on the same gear train, so half of them rotate clockwise, and half of them counterclockwise. Anyone who is assigned to read meters is given some training first.
@@EEVblog its security. the dimples are presses in as you see in a couple other critical places like where the counter is. that makes it nearly impossibe to duplicate or mess with the disk without the inspector seeing it. its VERY common in eastern europe to open these units, replace the disks and counters to give less counts and put it back together with new seals you can buy at any shady corner. different brands have different styles. some have small lines or quare dimples as siemens has and others have more intricate designs. its just a form of copy protection. a really good inspector in hungary (or bulgary, cant remember) found a meter with the "wrong" layout of dimpels. they were less well made and had slighty different spacing. they found several thousand of those fake meters in a period of a couple weeks. they were made in china and gave 30% less on the meter after checking. people that were found to have a fake meter were given insane punishments. several years in jail and fines that were like a years worth of salary. goverment does not like you stealing, that is their job....
when aluminium is dimpled it surface has stress on both sides and it get harden, so disk with that kind if dimple pattern is less flexible. There is reason that this aluminium disk need to be 'soft' aluminium, maybe it is pure aluminium. Other way to make it harder or less flexible is to have anodizing surface on it.
I used to work for Landis & Gyr (pronounced Gear) back in 1997. That meter is called a Plugin meter supplied for Queensland. Made in Mt Waverley Victoria. Most the parts came from Switzerland.
It looks like the Queensland one (they do like the odometer) but it says "Energy Australia" on the face plate which means it came from NSW (Eastern/Northern Sydney to the Hunter Valley).
It's only been a couple of years since my old school meter was removed from my house. The energy company got all confused when I kept on giving them meter readings less than the previous one in the summer months......due to the Solar PV sending it rotating backwards....:-)
@@rkan2 They are, there is no software involved, no easy cheating and no antenna telling the power company you have a 20yo washing machine. Replacement of these with electronic isnt for precision sake as you can see. It is for smart grid and dual rate customer fuckery
The turtle AMR still has the record of a automatic meter reader transmitting the reading over the power line. there was one in the outback of Australia. It read the disk spinning and counted the power. And then it would send the data over the power at ~120Hz in a narrow bandwidth signal. and it transmitted data at 33 minutes per bit. so that's 1/2000 baud.
Actually, Hunt Technologies’ TS1 system runs at a VERY low frequency… think it was between 5 and 15 Hz with .0015 hertz difference between adjacent transmitters, and it took over 24 hours to transmit a complete packet of information (hence the ‘turtle’ moniker). Other power line carrier systems like the Aclara system use spikes in the zero crossing interval to transmit the data, while Eaton’s system uses a higher frequency in the kHz range overlaid on the power line.
@@Renville80 Yes, but the low frequency was modulated by the switched cap into the 120Hz side bands. So the cap 1/2 cycle on and 1/2 cycle off created a 120 Hz signal and then the inverts created sidebands. I have some if someone wants to take them apart.
It’s so simple, yet complex at the same time! Stuff like this is amazing to me. Anything that computes via mechanics is so neat, like those Friedman calculators. Amazing thought is put into stuff like this
The same principle was used for over 100 years in electric transmission line “distance” relays (device 21) that measure both the fault current in a trash mission line and the distance to the fault. These are used to prevent tripping of multiple circuit breakers on a line when a fault is detected and to only isolate the portion of the transmission line where the fault occurred. The principle of torque angle as a measure of phase angle is the same. The term “torque” is still used today with digital programmable relays that do not use rotating discs. This confuses many young engineers! I’m a utility engineer, retired after 45 years.
I love the analog meter. When I was 6/7, I broke one of these old school meter. Used a dc motor to spin the dials with gear mechanism. It was fascinating for me at that age to use kinetic energy to show numerical values. Now after all these years, watching this video brings back memories. As always, great explaination Dave, my Aussie Teacher. Respect ++
Watt hour meters (the mechanical type) are beautiful works of engineering. With all the precision bearings and jeweled movements, and gear train for the totalizer. The old Westinghouse/GE time delay relays used in sub stations use very similar technology (eddy current motors) with magnetic drag for timing and contact placement. Also very beautiful pieces of equipment. I used to calibrate these watt hour meters and time delay relays for a local utility (DWP) so I have hands on with these and was always amazed with the engineering.
I like how it's simple, yet complex. Everything in there has to be just right for it to be accurate, all down to number of turns in the coil, to how far apart magnets are etc.
it might be interesting for a lot to learn more about it like the scale the disc has. The counter has an imprint of 187,5 rev per kWh so you can calculate your CURRENT CONSUMPTION based on the the time it needs to pass 5 marks for example cause the whole disc here is divided in 20 marks, not 360 or 36, just 20 which means each mark represents 1 / 20 or 5% 187,5 revs per kWh means that each rev represents roughly 1 / 200 of a kWh or 1 / 200 x 1000 Wh so it is just 5 Wh. and then you know that 4 marks out of 20 would mean roughly 1 Wh used. If it takes 20 seconds to pass 4 marks then it would mean 1 Wh in in 20 seconds, 3 Wh in a minute and 180 Wh in 1 h which tells us we had a 180 W load running over 1 hour. So you can read the consumption if you stop the time it needs to pass 10 marks or segments which would be half a rev. 3600 s / seconds stopped for half a rev x 1000 Wh / (187,5 x 2) imagine it would take 10 seconds for a half rev, then it would take 20 for a full rev and 3 revs every minute or 180 revs each hour. This would mean that 180 / 187,5 kwh would be used or we had used a load of 0,960 kW Let's assume it takes 20 seconds to achieve 1/4 rev then it would mean 3/4 revs per minute and 180 / 4 revs per hours = 45 revs and that means 45 / 187,5 kW of load or 0,240 kW or a 240 Watt load. That is the part you need to know to get behind your energy consumption. Start the water cattle and see the wheel turning a lot faster or the iron for your shirts. But you can start there at the good old ferraris once you know that the number of revs / kwh is the key to read and understand your current energy consumption. Most people here did not learn that.. For most energy consumption is still a secret and they did not learn the basics how to get behind what device needs what energy in a month or depending on the season of the year.
On North American watthour meters, there's always a value on the nameplate "Kh" - watthours per disc revolution, so you do this to clock the load: Kh x revolutions x 3600 / time(seconds) If you had a Kh=7.2 meter and it made 4 revolutions in 60 seconds, the average load over the past minute would be ~1700 watts. Very easy to do!
@@doctorzaius4084 That's what I thought that number meant but it doesn't make as much sense when it's on a digital meter like mine. I have a 6-state animation of a moving bar and instead of one Wh per complete cycle it's one Wh per frame. IIRC the meter says the Kh is 10 but which didn't make any sense.
@@eDoc2020 They made it more confusing with electronic meters, but it's still the same idea. Those little bars that scroll by are supposed to be a crude simulation of a disc rotating, so it's 10Wh for a complete "revolution" (i.e. it moves through all 6 spaces and back to where it began) not 10Wh per frame. The only exception to this that I'm aware of are Itron "CENTRON" meters where the Kh=1 and each time the dot blinks on or off, you count 1Wh. Dots/lines moving to the right means forward rotation (normal), to the left means reverse rotation - if you've got solar panels exporting power, for instance. A lot of smart meters also have a "load present" function as a standard display item, but it might not be obvious just from looking at them. You would need to know what the display codes mean, and whether or not there's a multiplier.
5:55 - magnetic brake is the term you're after. For fun take one apart and put that disk into a drill, spin it up then introduce a U or horseshoe magnet
I agree with some of the other comments regarding the dimples being there too keep the disks flat. The same tecnique has been used for many years on parts like motorcycle clutch plates, where they can also act as lube resevoirs .
Clever engineering right there. And the single turn on one of the coils on the magnetic ammeter portion acts like a shaded pole, thus saving the company that made it a bit money, and to keep it rather simple than installing a Copper ring on the shaded pole, forcing the disc rotor to favor the pole with three - four turns coil, thus only spinning in one direction generally. (If you reverse the ammeter coil polarity against the voltage coil, or flip the ammeter coil in the other direction, so it could spin the other direction, depending on how the motor is designed - your watt-hour meter could be modified to do that as it's much more simpler.)
As a fireman, pulling these out of socket is also a quick way to kill power to a residence. Where I live now, this isn't usually a big deal since the utility company is often right behind us, but we used it a lot more where I used to live.
The holes in the disk stabilize the centers of the eddy current vortices and force the disk to move rather than allowing the vortices to 'slide' across the disk. I'm not sure about the brushed stripes, but I think it might compensate for aluminum's thermal coefficient of conductivity.
I don't remember what it's called, but the dimpling is from a flattening process with a big press to make sure when they're stamping them out of the large sheet they're not warped.
Back in the 70s when I studied my EM course we used the mnemonic "ELI the ICE man" to remember the phase shift due to Inductors and Capacitors. But "CIVIL" is simpler!
Here in the states, the box the meter is installed into is put in by the electrician, then once the electrical inspection is passed, the power company comes out and installs the meter. That's why the meter just plugs into the box.
I hadn't seen CIVIL before here. Way back when I was learning electronics my instructor related "ELI the ICE man", which I found very easy to remember. He also gave us a PG version for remembering resistor color codes; but for some reason I currently am only able to remember the Navy version.
I likewise learned ELI the ICE man back in the 70s and also the “Navy” version of the color code, which I still remember so I guess it was an effective mnemonic. 😂
This has probably already been answered in the hundreds of previous comments, but I believe the dimples are too help make the disc flat and rigid, and the brush marks may have to do with balancing of the disc. Thank you for another great video!
Yep. Changed 4 & 8 GHz twats. Traveling Wave Tubes. The Reflex Klystron , Magnetrons and TWaT were part of my USAF career. Most gain is from antennas. Broke a 4GHz TWT in a Philco transceiver. A delicate procedure. FELDBERG GERMANY 1984-88
I remember someone who had a small hole in the bottom of his meter, with a paperclip up through the hole and caught through that disc hole to freeze the meter.
The dimples are there because the plate can be pressed flatter with dimples than without. I don't know the proper technical term but it has to do with spring back when you bend a piece of metal into shape. I guess with dimples you get easier into plastic deformation.
Your meter can spin in reverse direction with readings decreasing due to it( you started with 79686 units, which fell to 79683 units). Didn't expect that from Siemens. In India, our electromechanical meters come with a mechanism which prevents reverse rotation of the disk
Thanks for creating this video, I did my first internship at Siemens at the former Landiy & Gyr premises in Zug, Switzerland and it was interesting to see a part of the company's history
I might have missed it in the explanation, but the magnet doesn’t just keep the disc from spinning wildly, it’s actually part of the calculation itself(!) The disc multiplies the I and V components, resulting in a torque, and you’re right, if the magnet wasn’t there, the disc sound just keep accelerating. The drag induced by the magnet is *proportional to the speed of the disc* though, so a given amount of torque will translate into a specific speed of rotation. Voila, speed is proportional to V x I ! 😁
Dave, thank you; that was utterly fascinating. You've got me running down to the cellar to watch Eddy make the disc whizz round every time I put the kettle on!
@@tiemenfiat1321 They can be sensitive to magnetic fields, depending on the metering method. A shunt does not really care about magnetic fields, but if you use current transformers, then magnets could manipulate your accuracy. Another way magnets could have an effect, if you have a switching mode PSU, and then the external magnetic field could saturate the switching transformer, preventing the meter from working properly.
Your video gave me flashbacks to my time in the Meter & Test section of Prospect Electricity (Seven Hills depot) overhauling and calibrating meters similar to this one. The jewel bearings used to come in an applicator that released one at a time and were tiny. Anyway, enjoyed the video 👍
The holes in the disc are for testing, a laser is passed through the disk and you'll get a test pulse every time the laser passes through that hole. In the states, we perform three tests on meter. A full load test, a light load test, and a power factor test. Adjustments are made to the magnet in order to speed up and slow down the disc to calibrate the meter.
Ah yes, our old meter. When we got a quote to get a smart meter (which I was able to hack - good old software backdoors), the engineer said “Jesus, you didn’t tell me it was an old analog meter you had!”. That meter was installed when mainstream electricity first became available in our region and it had never been changed since then. We’ve still got that meter (not connected to mains, we’ve got it in a custom acrylic display case because of its history) because I love anything electrical and old/vintage.
Yes, it is amazing! Plus these things must be engineered for reliability and consistency over a few years or even decades, as it would be so damn impractical to cut off the power in order to swap the meter every year or two. I like the meter-base interface used in Australia - it allows for a very quick replacement (even without cutting the voltage off), way quicker than European meters, because they have screw terminals on the bottom side, covered with a plate that is sealed to prevent tampering. Oh, and retarding the meters with neodymium magnets was an energy companies' nightmare to the point that they really welcomed the modern electronic meters... By the way, I wonder how a double-tariff electromechanical meter works.
if i had to design one: a small motor that drives a reduction gear such that it rotates at 1rev/day. and an extrusion on on half on the top side of the gear and bottom on on the other half of the gear. the extrusions actuate switches that connect either one or the other meter disc driving mechanism to the circuit.
We have similar meter mounts in North America, except ours have four or five tabs because of our wacky split-voltage system. Regarding double meters, I think they superimposed signals on the power line to switch between the two modes. My guess for the actual metering part is that the current coils on each meter would be in series and they would switch the voltage coils on and off to determine which meter spins.
double tariff mechanical watt meter works in conjuction with relay switch. Every day in same time (im my case at 9PM and 7AM) electromotor with generator starts in my local substation. When generator is spinning it produces 1060Hz ripple and send it to electric grid for few minutes. Mine relayed switch "hears" that ripple and switches tariff mode on watt meter. After few minutes generator disconects from grid and shuts down. It starts again when is time for another tariff change... Generator works on very accurate substation internal clock and everthing is relay powered there, very simple and robust. System works so good that mine electricity company dosn't follow seasonal hour change. During winter hours cheap tariff is from 9PM to 7AM, and during summer time cheap is from 10PM to 8AM. substations internal clock is never changed, so company save a lot of money on maintenance because God knows how many substation and clock and generator systems they have. They just move tarifs + - 1 hour and don't change anything in their system
@@lordred7462 That motor generator system is called the Zellweger ripple system, used for tariff control, load shedding hotwater circuits, streetlights etc. In Auckland it is 1050 Hertz.
Hey Dave, you actually don’t even have to disassemble the unit to pull it out of the receptacle. There’s a puller tool linemen use to pull it out as these things need replaced often enough to warrant it.
What you could do is make a small diameter hole through the plastic casing with a dentist drill or heated wire, place a small metal rod through that makes contact with the disc and slow it down that way. Just remember to remove it before they come to measure it and do not to get too greedy. For good measure, cover the meter in some dust so the whole is less visible ;)
Used to be called buzz boxes here, a small transformer that was wired across the meter to slow or reverse the disc, many of the later meters had flags that popped out if the disc rotated in reverse as a visual display
It's interesting, how good it is for measuring low-pfc (in terms of current shape, not a passive power) units, like some LED bulbs. Some modern (electronic) units exhibits "gigantic" error here, as it was shown in one article (authors were from netherlands, afair).
I think they would pretty good with accurately measuring power on abnormal current waveforms. It's abnormal _voltage_ waveforms I would be more concerned about.
4:12 Why do the two magnetic fields (V * I) multiply together rather than add? The explanation later (5:16 and then later in the video) only explained about how the phase difference models the power factor, but not why the two fields multiply together to give us power V*I rather than adding V+I
@@WacKEDmaN No, that doesn't answer my question. I know that P = V*I. But in the video he said that the device calculates V*I. But why would having two magnetic fields overlapping multiply the fields? Shouldn't it add the fields instead? Looking for an explanation of why the device somehow calculates the multiple of V and I rather than summing them, so that it can compute the power correctly.
Here in Russia we had quite different design of watt-hours itself but its discs has that stamped square dots too. It's definitely not a voluntarism of designers. I think they're works quite similar to how slits on unipolar machines discs works. Like optimizing paths of indused current. By the way, one of the most popular riddles today. Why does a unipolar machine generate exactly the same voltage if a round magnet rotates with its disk, as when the disk rotates, but the magnet does not.
The case is probably polycarbonate vs. acrylic. At a trade show in Chicago around 1975 GE Plastics had a demonstration of the durability of Lexan (polycarbonate). The demonstration consisted of a power meter cover, similar to the one in the video, and a standard 10 pound sledge hammer on about a 12 foot shaft. The top of the shaft was hinged. When a rest vertically the sledge hammer just touched the Lexan meter case. The sledge hammer was raised to horizontal and released to hit the meter case. You could see the Lexan case deform by a couple of inches or so and the demo repeated several times an hour. GE Plastics made their point.
A thing of beauty and not remotely hackable - unlike "advanced" "smart" meters. It also can't "decide" what temp it will allow your heating/cooling to run at. This degree of remote control is reported as being done with "smart (arsed)" meters overseas. Might be a good topic for a few vids :) Love your channels, Dave - Happy New year!
I noticed they arranged the contacts so that you can only mount the meter in the correct direction. Here in the US we have center tapped neutral on 220 V, since the top and bottom are basically two hot legs the meter has to handle two hot legs( I cant remember if the neutral is connected to the meter.) You can turn the meter upside down and plug it back in and the meter will count backwards, so you HAVE to have the meter tamper locked.
The power company swapped out the old school meter about 8 years ago and I have to say I found the old ones a LOT easier to read. I use an electric lawn mower and it was cool to stand next to it, turn on the mower and watch the wheel go crazy. Now I don't understand the output of the digital meter at all, nor can I see the reaction with the lawn mower. But, I guess it keeps a meter reader out of the back yard every month. I loved the teardown, I understand most of it, though I never studied AC circuits so the interaction between the volt induced eddy currents and the current induced eddy currents is still not fully understood, but I do delight in the elegant engineering the device presents.
You must have a completely different kind of digital meter then. Here in North America they have an LCD which directly displays the kWh count. Definitely easier than the counter-rotating hands we needed to deal with before then.
You would love some old electric grid protection relays. All mechanical relays that protect lines, buses, transformers, etc. Distance, differential, over current and more. Many are still in service and still accurate to +-5%. Very similar to mechanical meters except for 50x more stuff packet into one.
Decades ago, when I was much younger, I tried to see if I could get that disc to spin fast enough to break the sound barrier. Unfortunately the only thing that broke the sound barrier was my father's temper, after seeing the electric bill that month. 😁 ⚡️
The box and plug design on these meters in the U.S. is a bit different. The way they are built it is physically possible to turn the meter upside down in the housing, which will make the meter run backwards (illegal, of course.)
My favorite line was the part about the steady eddy current. :) It was truly fascinating to watch you take it apart. Could the dimples be there to reduce drag in the air flow, like on a golf ball?
The dimples on a golf ball work to induce turbulent air flow, which at the speeds and spins seen in golf balls, will increase range and shot repeatability. If the disk was spinning quickly enough to induce turbulence in the air on its surface, the whole device would probably tear itself apart. Also they probably wouldn't need to bother with the permanent magnet to stop the disk continuously accelerating as they'd just have designed it so air resistance would do the job.
Ameran wanted to replace analog watt meter for a digital one. I refused. They now tack on a $20 a month penalty fee. I refused because when my mother allowed it on hers, her monthly bill increased substantially.
In Serbia, one guy made a very small hole on the glass and put some dead bugs on to the disc, which made it jam little bit and turn slower 😎 they couldn't prove it was his fault as he was passing much less than he was suppose to 😂
Hmm I guess you could simulate something that looked like a rock that was shot out of a lawn mower or something to impact the glass. A small rock and a slingshot would be the way to go.
yes, nice you can stop it or spin it with the magnet, I found some damaged one that kept running with no load without stopping, some with mechanical damage due to resonance caused from harmonics or from people with magnets playing around. in some probes, north side of the city they spin faster with no load, the south side of the city, the same meter spin slower with no load. The new ones can even document the reactive power.
We got the basics of this in the first year of university Physics classes, then revisited it two years later to solve the full set of field equations for both ideal and real materials, and then measure the difference in the lab to get the right values in the model for the real materials and see the affect of mechanical design choices. The hardest part, by far, was summing the effects of all the fields in the disc and the topology (shape) of the induced currents.
We also had to allow for the thermodynamics. A factor in the size and design of the disc is to dissipate heat, particularly to minimize peak local heating during high loads, and to have consistent behavior during the full range of environmental conditions. Aluminum is chosen for the disc because it has a good balance between conductivity and heat transfer while also minimizing angular inertia. Iron alloys could not be used because they could be magnetized (though we did not consider austenitic stainless steels). A copper alloy could work, but the disc mechanical design would need to be very different, with affects that would ripple through to the rest of the meter design.
Now that sounds like a proper degree, thanks for the info.
@@paulmeynell8866 yep someone with a degree worth having...lol
Sounds like you went to a good program/school, thanks for the additional info
Austenitic stainless still has a magnetic proponent.
@@jeffwombold9167 proponent? I do not think that means what you think it means.
Out of passing interest... eons ago, a friend lived in a large apartment complex. All the electric meters were on on a wall in the laundry room... there must have been 50 or more. He was doing laundry one day, & out of mere curiosity found his meter & noticed it rotating quite fast... then noted it speeding/slowing in time various laundry machines cycling on/off! Cheesed him off... but to be sure he ran & turned off his main breaker, & returned to find the same! He called & reported to his DWP; and they were there seemingly within minutes. It seems the landlord had jumpers behind that wall & rotated the laundry and common areas to different meters on a regular basis. He said it turned into a colossal legal S storm that lasted about a year.
WTF! Can't you just share laundry toom electricity costs between everyone? must be expensive elevtricity there!
@@rkan2 Or charge for use (i.e. a "coin op")? Stealing power from individual residents is a felony.
@@jfbeam I'm guessing it _was_ coin operated, the owner was probably trying to reduce the expenses.
I had a friend in a similar situation. Everything in his apartment was turned off, but the meter was still turning. So, he pulled his main fuse and put it in a drawer and left for a weeks vacation. It turned out that they ran the emergency lighting off his circuit, and since they couldn't find his main fuse holder, they had to rewire the emergency lighting elsewhere. They were not happy, but couldn't do much about it.
@@johnhaller5851 that's surely illegal, emergency lightning should be connected to a separate source, not to an individual apartment's meter board/meter.
I think the grid pattern of divots in the rotor is intended to make the rotor acceptably flat. When you stamp sheet metal, it often won't come out flat if you just smash it between two flat dies. The blank was almost flat to begin with, so the tiny amount it moves during stamping isn't enough to overcome the metal's elastic limit. When the press opens, the stamping springs back to it's original almost-but-not-quite flat shape.
But if you make little divots everywhere, you stretch the metal much more. By exceeding the metal's elastic limit, you convince it to take on the shape of the flat dies.
And you get a thicker disc with the same piece of metal.
Thanks, I always thought it was something like that, as I've only ever seen the pattern on folded metal parts that required a reasonable amount of precision, like a sheet of mild steel inside a printer with posts for mounting gears and motors etc.
@@soupisgoodfood42 Yep. You used to see this pattern all the time on chassis components in camera and electronic gear that required a modicum of precision. I've seen it in movie cameras, cassette recorders, VCRs and so forth. Anymore you don't see it so much, because so many consumer applications have replaced precision mechanicals (expensive) with electronics (inexpensive and usually perform better). A printer is one of the few places where a consumer device still requires high precision.
woah!!! that's a really cool and simple way to solve a complicated problem! Do u know why most utility companies chose to go with digital readers now days? there was alot of backlash in my city about it because it supposedly gave the electric companies too much control?
@@fitingsthdown The primary reason would be cost, particularly for the components to read the meter remotely since that's a lot easier to do with digital technology. If you don't need remote reading the cost differential is a lot less (and might actually be negative), but sending a person around to look at each meter and record the current value on it is quite expensive when you have millions of meters that need to be read each month!
You have to remember that V x I x COS(theta) on the disc creates a TORQUE, not an RPM. That means once the friction is overcome, it would go faster and faster. Those permanent magnets provide a drag proportional to the speed of the disc. Without the drag magnets it just won't record watt-hours. When you add drag proportional to speed, and TORQUE proportional to Watts, you get Watt-Hour.
Great - thanks! I knew there had to be some such mechanism but didn't know what and where it was.
The magnets provide time in the equation. Thank you
The drag is from "eddy current braking", which is responsible for the neat effect of dropping a strong magnet through a copper pipe ( th-cam.com/video/lDIGFF1xfPM/w-d-xo.html ). Side story: We had an interactive TV exercycle that drove an electromagnet that was next to an aluminum disk which was spun by the bicycle pedals. After a couple minutes of peddling, I wondered where all the energy was going. My curiosity was quicker than my smarts as I reached down to touch the disk. WOW! that thing was hot!
How do you calculate how much drag you need? Also, why is it proportional?
@@atexnik The voltage induced in the disc by the rotation of the disc in the magnetic field from the permanent magnets will be proportional to the rotational velocity of the disc (Faraday's law). This voltage will cause a current to flow in the disc that is proportional to the voltage (Ohm's law). This current will give rise to a torque that is proportional to the current and hence proportional to the rotational velocity of the disc.
To continue beyond your question: This torque opposes the torque caused by V I Cos(Theta), the power consumed by the customer. For any given power consumption, the disc will settle at a rotational velocity where the torque from the power consumed by the customer is matched by the torque from the drag effect (because in that situation there is no net torque to accelerate or decelerate the disc). Hence the rotational velocity of the disc is proportional to the power consumed by the customer.
The scale factor for the drag torque effect could be chosen so that the bearing and gearing friction is not a problem for low consumed power, and disc rotational speed is not a problem for high consumed power. These requirements conflict, so a compromise would be chosen in practice.
Years ago I had a bundle of wires inside a conduit and needed to figure out which of the 20 or so wires was connected to a particular branch circuit. I made sure every appliance was turned off, then connected a hair dryer on high to the branch circuit I was trying to identify. I then held a 1" x 3/4" neodymium magnet close to the wire bundle and spread the wires apart. It was very easy to identify the correct wire, the magnet was vibrating in my hand just like you showed in the video. A very useful method.
Very interesting 🧐 effects of the 50/60hz on the magnetic 🧲 fields causing the shaking.
@@ZaneDaMagicPufferDragon Also works great identifying DC circuits. The wire will be pulled toward the magnet or pushed away depending on the magnet's orientation.
Cody from "Cody's Lab" had a small piece of magnet inserted into the skin, with that he could sense magnetic flux near it, like high current in a wire. Basically enabling a 6:th sense.
@@Paxmax I used to have a magnet like that too. I could feel sufficently strong magnetic flux (removing stir bars in the lab was also a fun party trick). I could really feel it when I was MIG welding. No pain with that, but it was the only times I would have my hand around 50+ A. I could also feel the flux around motors for a good 6" inches.
@@Paxmax I think he removed it because a piece of it broke.
I love the mechanical solutions of the time just before the digital age, they are so incredibly clever always.
I think most of them reached their topmost point of advancement before taken down by digital stuff. Mechanical stuff of the past decades are always fascinating as they're bot reliable and performing good.
You mean analog. Lol, even the digital stuff is mechanical.
That style of plug in meter base can actually have the meter installed rotated 90deg, when in this arrangement none of the electrical connections are made and the meter is just acting as a cover for the bare terminals.
This function is used when the electricity company wants to disconnect supply from a property without removing the meter from site as the meter is tied to the address. It is used mainly when disconnecting people for non payment or when a rental property is unoccupied for an extended period and has the advantage that the meter can have the seals fitted to prevent the customer from tampering with the disconnection.
Source - former metering tech
The amount of accumulated knowledge built into these things is quite amazing
You should see Technology Connections take apart an old analog jukebox. The selector mechanism? Like, daaaaamn.
I worked on meters for 4 years, and that was the most concise lecture I have yet seen.
We had a mechanical meter for a little while with a solar system. The retailer's systems eventually managed to cope with negative electricity usage each month, although eventually they fitted a non smart digitial meter that only lasted a few months before they replaced it again with one with a radio. It was pretty fun to watch the mechanical meter on a bright day when someone was welding as it would be spinning moderately fast backwards, before spinning very fast forwards for a few seconds, then going back to its usual spinning backwards :).
Actually here... first I had a digital meter which was not able to run backwards for the solar-panels so the installation was changed into a mechanical meter for years but then needed to be replaced with a 'Smart meter'. Well, yes, smart for the company, not for me.
Normally I use about the same as the solarpanels provide, thus the old meter was just standing still for days and sometimes going a bit forward in the night, going back during daytime. Well, that is not possible anymore and much more measured energy now with the Smart meter...
@@elvinhaak The house always wins. :-)
@@elvinhaak nowadays they put 2 meters, but it doesn't matter, because they buy energy from you cheaper than they sell, no matter what.
so you best not put the energy back when you don't need. put it into cryptocurrency, lol.
@@elvinhaak id get my own mechanical meter in series with it just to be sure
Funny. Most, if not all, mechanical electricity meters in my country have a built-in power flow backstop. If you feed power to the grid, the discs rotates backwards, but whell with digits does not
Hi Dave .. you did an excellent job explaining all this. Back in the 80s I spent over 10yrs working for a power company calibrating single & 3 phase meters and troubleshooting meter problems. People used to drill holes through the case and poke a bit of wire into the brake magnet (and of course remove it before the meter reader was due) and play around trying to slow them down with an external magnet. Our own experiments with external magnets showed that you are just as likely to speed the meter up ... This particular meter like most later ones has magnetic suspension usng the two repulsion magnets at the bottom combined with an upper and lower centering guide needle .. We typically tested meter calibration at both unity and .5 PF (Cos 60), the power factor adjust is the 2 copper vanes on the rotatable shaft. Full load adj usually involves movement of the brake magnet but this later L&G appears to be using a different form of brake magnet adjustment
Hi, I do have a similar job in the "Zählerwerkstatt" (so called in german) as you in the late 70s. It was the time where I get my first programmable calculator (a TI59).So I wrote programs to help us calibrating the meters. It is funny to look back to those times... I'm living in northern germany. I wish you a happy new year and take care.
The trick is to get an old low voltage/high current filament and wire the secondary across the meter, one lead on an AC outlet the other on the mains. Then put a Variac on the primary of the filament transformer. as you raise the Variac voltage the disc slows down and starts the disc running backward. This is of course purely theoretical and is for educational purposes only.
drilling a hole from the neighbor exactly to the correct place and putting a wood branch did the trick of slowing down the disc for me. But yours are better.
Faraday's law: The induced emf in the disk and the induced eddy current in the disk is proportional to the flux rate of change. The torque on the disk is proportional to the eddy current times the instantaneous magnetic field. When voltage is maximum (positive or negative), it provides a background magnetic field centered on the coil assembly so that the offset eddy current induced by the rapidly changing current is attracted or repelled. When the current is maximum (positive or negative), it provides a background magnetic field offset from the center that attracts or repels the centered eddy current generated by the quickly changing voltage. All four torques are in the same direction. Torque provides angular acceleration except that the permanent magnets' eddy currents provide opposite torque proportional to disk speed. Together the disk's speed is in equilibrium at some speed proportional to the IV's torque... proportional to power. The counter integrates the disk's speed (power) wrt time to yield Watt-hours. Very sharp spikes are filtered out by the disk's inertia.
This was really fascinating. I always wondered how those old meters work. Thanks Dave for the great explanation. Please do more of those educational videos.
The dimples on the disc can be scanned with a photo electric cell during calibration. It speeds up the testing process when a line of meters is on the test bench. The readers are mounted above the meter and read the 10 dimples as the reflect the light back from the opto LED in the photocel. So for each revolution of the disc, 10 pulses are 'generated'. The Landis & Gyr CL 147 has similar patterns on the disc, which was a predecessor of this meter, made in the UK.
Decades ago as a young pre-teen technology enthusiast I got one of these kWh meters from my grandmother's house renovation and of course took it apart. I don't think I then understood how it works at all, it was just an interesting gadget to dismantle :) I vaguely remember wondering how the simple metal disc could spin when there is no contact with anything but the counter.
Oh I just remembered that it had a kind of U-shaped magnet almost like in the cartoons, except the ends were bent to almost close the shape to an O, but then again bent outward to become parallel to the long sides so that the gap in between was just large enough to allow the disc to spin freely in between. Or maybe if you imagine the Greek letter omega with just the horizontal "feet" clipped off :) I had that magnet a long time in my gadget collection as a fun thing to play with from time to time.
They are fun to tear down. I love the look and feel of the mechanical ones.
Had a funny one for you.
Had an analogue meter on a remote site that was permanently shut down; site uses like $150/month in power. After the site was shut-down, 3 months went by, utility company swapped the utility meter, and then another billing cycle went by and they billed us $15,000 because they thought the meter rolled over. What a great day at the office. 🤙
the old "lets throw that on his side of the fence and see if they notice" trick
My uncle worked for the local utility company. He saw every trick imaginable to alter the meter. He made sure his house had the "best" one
It feels nice when you compliment this precision product of my home country, Switzerland. The company name is spoken like „Landes and Ger“ as the „y“ is spoken like a „e“ in English or an short „i“ in Alemannic. Even in my current flat there are still Landis & Gyr devices at work. Indestructible and very reliable.
The holy grail of electricity meters!
I was an electrician in the states for many years and one of my hobbies was collecting vintage A-base watthour meters. I have meters going back to the early 1900's and a few more modern ones. I made table lamps out of a few of the modern ones.. These meters are fascinating and beautiful in their simplicity. A voltage coil and an amperage coil and a magnet.
3 Phase meters are interesting too, they just have 3 of those disks on the same spindle. Being connected on one spindle it will measure true resulting power. These measure true power regeardless of the noise on the powerlines due to switching powersupplies, led lamps and other odd consumers. Digital meters need all kinds of clever engineering to get the same accurate result. Those mechanical meters do not need any of it and are just accurate, even 50 year old ones.
Last I saw one of these for three phase it still only had one disk, I would assume that it have some mechanics to transmitt and if needed add together the three inputa
Ours got 2 disks.
Thanks for the info. I was just wondering how accurate these were with large amounts of harmonic distortion in the load. I have one of these from the 40s mounted on a panel that I use to track hydroponics lighting energy usage. It's almost completely identical to this except it has dial indicators, but the internals are essentially the same.
The earliest ones as well as many European ones have multiple disks, but many North American models have two or three stators around the edge of the disk. The single disk meters actually have laminated disks to minimize interference between the stators.
@@liam3284 Var hour meters have a special transformer in series with the voltage coils to shift the voltage field another 90 degrees.
It is truly amazing how accurate these meters can measure, not to forget how little they cost. It is like the predecessor of hard drives in these regards.
I obtained one, left over from a power company customer, and built it into a benchtop power meter. I discovered that it only works well when mounted with the rotating disk axis close to vertical. It has very little friction in that orientation, but much more friction when tilted. When rotated 90 degrees from vertical, it didn't move at all.,
I wondered for years how these things work, thank you Dave!
The temperature compensation blew my fucking mind. It's amazing how much engineering goes into these simple-seeming little electromechanical devices.
If you want to see real insanity, look at marine chronometers from the 1700s... Mechanical timekeeping good to 1 second in 100 days for finding longitude at sea, when modern all mechanical watches (Even the ones with the certified marine chronometer tag) are only guaranteed good to a few seconds a day. At the time they were the most complex devices ever manufactured - temperature compensation was a huge component of making them keep good time.
The meters in my 1970's block are still the clock face dials. None of this "odometer rubbish". 😀😀😀
Mid 2000s neighborhood here. I also have the clock face dials! My neighbor has a 7-segment face though
Ah, they look more like water meters?
The pointer registers have the advantage of consistent friction, while all cyclometer registers have a weight to help push the last dial from 9 to 0, as multiple drums need to advance in the same interval.
The dials are all on the same gear train, so half of them rotate clockwise, and half of them counterclockwise. Anyone who is assigned to read meters is given some training first.
I wonder if the dimples are to stop the disc warping over temperature changes, reducing surface stresses
Possible. There has to be something to it, you don't just go to that effort for no reason.
Probably a similar reason golf balls have dimples?
@@EEVblog its security. the dimples are presses in as you see in a couple other critical places like where the counter is. that makes it nearly impossibe to duplicate or mess with the disk without the inspector seeing it. its VERY common in eastern europe to open these units, replace the disks and counters to give less counts and put it back together with new seals you can buy at any shady corner. different brands have different styles. some have small lines or quare dimples as siemens has and others have more intricate designs. its just a form of copy protection. a really good inspector in hungary (or bulgary, cant remember) found a meter with the "wrong" layout of dimpels. they were less well made and had slighty different spacing. they found several thousand of those fake meters in a period of a couple weeks. they were made in china and gave 30% less on the meter after checking. people that were found to have a fake meter were given insane punishments. several years in jail and fines that were like a years worth of salary. goverment does not like you stealing, that is their job....
when aluminium is dimpled it surface has stress on both sides and it get harden, so disk with that kind if dimple pattern is less flexible. There is reason that this aluminium disk need to be 'soft' aluminium, maybe it is pure aluminium. Other way to make it harder or less flexible is to have anodizing surface on it.
But it's actually increasing surface stresses. But yeah they can be to increase rigidity by making some stressed zones.
This teaches and demonstrates the basic principles with a practical example as clear and efficient as possible. Another classic video.
We still have analog power meters at my home.
It's fun to see it, spinning like a motor when a lot of appliences are running inside house!
With todays electric prices it’s not fun to see it spin at all..
I used to work for Landis & Gyr (pronounced Gear) back in 1997. That meter is called a Plugin meter supplied for Queensland. Made in Mt Waverley Victoria. Most the parts came from Switzerland.
It looks like the Queensland one (they do like the odometer) but it says "Energy Australia" on the face plate which means it came from NSW (Eastern/Northern Sydney to the Hunter Valley).
It's only been a couple of years since my old school meter was removed from my house. The energy company got all confused when I kept on giving them meter readings less than the previous one in the summer months......due to the Solar PV sending it rotating backwards....:-)
Somehow you feel like these dumb meters could actually be better than the newer meters with net metering...
@@rkan2 They are, there is no software involved, no easy cheating and no antenna telling the power company you have a 20yo washing machine. Replacement of these with electronic isnt for precision sake as you can see. It is for smart grid and dual rate customer fuckery
The turtle AMR still has the record of a automatic meter reader transmitting the reading over the power line. there was one in the outback of Australia. It read the disk spinning and counted the power. And then it would send the data over the power at ~120Hz in a narrow bandwidth signal. and it transmitted data at 33 minutes per bit. so that's 1/2000 baud.
Actually, Hunt Technologies’ TS1 system runs at a VERY low frequency… think it was between 5 and 15 Hz with .0015 hertz difference between adjacent transmitters, and it took over 24 hours to transmit a complete packet of information (hence the ‘turtle’ moniker). Other power line carrier systems like the Aclara system use spikes in the zero crossing interval to transmit the data, while Eaton’s system uses a higher frequency in the kHz range overlaid on the power line.
@@Renville80 Yes, but the low frequency was modulated by the switched cap into the 120Hz side bands. So the cap 1/2 cycle on and 1/2 cycle off created a 120 Hz signal and then the inverts created sidebands. I have some if someone wants to take them apart.
It’s so simple, yet complex at the same time! Stuff like this is amazing to me. Anything that computes via mechanics is so neat, like those Friedman calculators. Amazing thought is put into stuff like this
The same principle was used for over 100 years in electric transmission line “distance” relays (device 21) that measure both the fault current in a trash mission line and the distance to the fault. These are used to prevent tripping of multiple circuit breakers on a line when a fault is detected and to only isolate the portion of the transmission line where the fault occurred. The principle of torque angle as a measure of phase angle is the same. The term “torque” is still used today with digital programmable relays that do not use rotating discs. This confuses many young engineers! I’m a utility engineer, retired after 45 years.
Also used for time relays in substations for fault tripping.
I like how on the front it has an explanation of how base 10 works
I love the analog meter. When I was 6/7, I broke one of these old school meter. Used a dc motor to spin the dials with gear mechanism. It was fascinating for me at that age to use kinetic energy to show numerical values. Now after all these years, watching this video brings back memories. As always, great explaination Dave, my Aussie Teacher. Respect ++
Oh no.i did same thing with my brother.we broke school meter and dismantle that.😮
Watt hour meters (the mechanical type) are beautiful works of engineering. With all the precision bearings and jeweled movements, and gear train for the totalizer.
The old Westinghouse/GE time delay relays used in sub stations use very similar technology (eddy current motors) with magnetic drag for timing and contact placement. Also very beautiful pieces of equipment.
I used to calibrate these watt hour meters and time delay relays for a local utility (DWP) so I have hands on with these and was always amazed with the engineering.
The lengths people go to make profit off other people is ridiculous
I like how it's simple, yet complex. Everything in there has to be just right for it to be accurate, all down to number of turns in the coil, to how far apart magnets are etc.
it might be interesting for a lot to learn more about it like the scale the disc has.
The counter has an imprint of 187,5 rev per kWh so you can calculate your CURRENT CONSUMPTION based on the the time it needs to pass 5 marks for example cause the whole disc here is divided in 20 marks, not 360 or 36, just 20 which means each mark represents 1 / 20 or 5%
187,5 revs per kWh means that each rev represents roughly 1 / 200 of a kWh or 1 / 200 x 1000 Wh so it is just 5 Wh.
and then you know that 4 marks out of 20 would mean roughly 1 Wh used.
If it takes 20 seconds to pass 4 marks then it would mean 1 Wh in in 20 seconds, 3 Wh in a minute and 180 Wh in 1 h which tells us we had a 180 W load running over 1 hour.
So you can read the consumption if you stop the time it needs to pass 10 marks or segments which would be half a rev.
3600 s / seconds stopped for half a rev x 1000 Wh / (187,5 x 2)
imagine it would take 10 seconds for a half rev, then it would take 20 for a full rev and 3 revs every minute or 180 revs each hour.
This would mean that 180 / 187,5 kwh would be used or we had used a load of 0,960 kW
Let's assume it takes 20 seconds to achieve 1/4 rev then it would mean 3/4 revs per minute and 180 / 4 revs per hours = 45 revs and that means 45 / 187,5 kW of load or 0,240 kW or a 240 Watt load.
That is the part you need to know to get behind your energy consumption. Start the water cattle and see the wheel turning a lot faster or the iron for your shirts. But you can start there at the good old ferraris once you know that the number of revs / kwh is the key to read and understand your current energy consumption.
Most people here did not learn that.. For most energy consumption is still a secret and they did not learn the basics how to get behind what device needs what energy in a month or depending on the season of the year.
On North American watthour meters, there's always a value on the nameplate "Kh" - watthours per disc revolution, so you do this to clock the load:
Kh x revolutions x 3600 / time(seconds)
If you had a Kh=7.2 meter and it made 4 revolutions in 60 seconds, the average load over the past minute would be ~1700 watts. Very easy to do!
Or perhaps most people just don't care. you pay the bill and move on with your life.
@@doctorzaius4084 That's what I thought that number meant but it doesn't make as much sense when it's on a digital meter like mine. I have a 6-state animation of a moving bar and instead of one Wh per complete cycle it's one Wh per frame. IIRC the meter says the Kh is 10 but which didn't make any sense.
@@eDoc2020 They made it more confusing with electronic meters, but it's still the same idea. Those little bars that scroll by are supposed to be a crude simulation of a disc rotating, so it's 10Wh for a complete "revolution" (i.e. it moves through all 6 spaces and back to where it began) not 10Wh per frame. The only exception to this that I'm aware of are Itron "CENTRON" meters where the Kh=1 and each time the dot blinks on or off, you count 1Wh. Dots/lines moving to the right means forward rotation (normal), to the left means reverse rotation - if you've got solar panels exporting power, for instance.
A lot of smart meters also have a "load present" function as a standard display item, but it might not be obvious just from looking at them. You would need to know what the display codes mean, and whether or not there's a multiplier.
@@doctorzaius4084 Those Itron meters are the only ones I see used over here.
5:55 - magnetic brake is the term you're after. For fun take one apart and put that disk into a drill, spin it up then introduce a U or horseshoe magnet
I agree with some of the other comments regarding the dimples being there too keep the disks flat. The same tecnique has been used for many years on parts like motorcycle clutch plates, where they can also act as lube resevoirs .
The mundane things in life that we often pay little attention to are often the most fascinating to look at and break down, glad i'm not the only one!
Clever engineering right there. And the single turn on one of the coils on the magnetic ammeter portion acts like a shaded pole, thus saving the company that made it a bit money, and to keep it rather simple than installing a Copper ring on the shaded pole, forcing the disc rotor to favor the pole with three - four turns coil, thus only spinning in one direction generally. (If you reverse the ammeter coil polarity against the voltage coil, or flip the ammeter coil in the other direction, so it could spin the other direction, depending on how the motor is designed - your watt-hour meter could be modified to do that as it's much more simpler.)
As a fireman, pulling these out of socket is also a quick way to kill power to a residence. Where I live now, this isn't usually a big deal since the utility company is often right behind us, but we used it a lot more where I used to live.
The holes in the disk stabilize the centers of the eddy current vortices and force the disk to move rather than allowing the vortices to 'slide' across the disk. I'm not sure about the brushed stripes, but I think it might compensate for aluminum's thermal coefficient of conductivity.
I don't remember what it's called, but the dimpling is from a flattening process with a big press to make sure when they're stamping them out of the large sheet they're not warped.
Back in the 70s when I studied my EM course we used the mnemonic "ELI the ICE man" to remember the phase shift due to Inductors and Capacitors. But "CIVIL" is simpler!
Here in the states, the box the meter is installed into is put in by the electrician, then once the electrical inspection is passed, the power company comes out and installs the meter. That's why the meter just plugs into the box.
I hadn't seen CIVIL before here. Way back when I was learning electronics my instructor related "ELI the ICE man", which I found very easy to remember. He also gave us a PG version for remembering resistor color codes; but for some reason I currently am only able to remember the Navy version.
Bad Boys...utter that now and you get nailed for sexual harassment. There's even a documentary about it. Amazing how low the threshold is for some...
@@cyberzeus7343 I am triggered at your use of the words bad boys ! REEEEEEEEEEEEEEEEEEE!
I likewise learned ELI the ICE man back in the 70s and also the “Navy” version of the color code, which I still remember so I guess it was an effective mnemonic. 😂
I’ve always been fascinated by these, maybe a little obsessed, thanks for the breakdown.
This has probably already been answered in the hundreds of previous comments, but I believe the dimples are too help make the disc flat and rigid, and the brush marks may have to do with balancing of the disc.
Thank you for another great video!
I was a Meter reader until mid 2021 (Perth, Western Australia) and I never encountered that particular Meter.
Yep. Changed 4 & 8 GHz twats. Traveling Wave Tubes. The Reflex Klystron , Magnetrons and TWaT were part of my USAF career. Most gain is from antennas. Broke a 4GHz TWT in a Philco transceiver. A delicate procedure. FELDBERG GERMANY 1984-88
I've always wondered how these meters work and the comments go deeper.
nicely done sir.
I remember someone who had a small hole in the bottom of his meter, with a paperclip up through the hole and caught through that disc hole to freeze the meter.
I freaking love your channel, along with AvE, Mustie1, big Clive it just gives me joy and a good feeling inside!
The dimples are there because the plate can be pressed flatter with dimples than without. I don't know the proper technical term but it has to do with spring back when you bend a piece of metal into shape. I guess with dimples you get easier into plastic deformation.
Your meter can spin in reverse direction with readings decreasing due to it( you started with 79686 units, which fell to 79683 units). Didn't expect that from Siemens. In India, our electromechanical meters come with a mechanism which prevents reverse rotation of the disk
Our electromechanical meters can be rotated backwards. But only the DISC can while the readings can't,😊
Thanks for creating this video, I did my first internship at Siemens at the former Landiy & Gyr premises in Zug, Switzerland and it was interesting to see a part of the company's history
I might have missed it in the explanation, but the magnet doesn’t just keep the disc from spinning wildly, it’s actually part of the calculation itself(!) The disc multiplies the I and V components, resulting in a torque, and you’re right, if the magnet wasn’t there, the disc sound just keep accelerating. The drag induced by the magnet is *proportional to the speed of the disc* though, so a given amount of torque will translate into a specific speed of rotation. Voila, speed is proportional to V x I ! 😁
it's so simple, yet really amazing piece of engineering and problem solving.
Dave, thank you; that was utterly fascinating. You've got me running down to the cellar to watch Eddy make the disc whizz round every time I put the kettle on!
Bring out your magnets :) One of the alerts in smartmeters is to report on strong magnetic fields near the meter.
Is a smartmeter sensitive to magnetic fields? I would expect a shunt and than some software to calculate real power.
@@tiemenfiat1321 They can be sensitive to magnetic fields, depending on the metering method. A shunt does not really care about magnetic fields, but if you use current transformers, then magnets could manipulate your accuracy. Another way magnets could have an effect, if you have a switching mode PSU, and then the external magnetic field could saturate the switching transformer, preventing the meter from working properly.
Your video gave me flashbacks to my time in the Meter & Test section of Prospect Electricity (Seven Hills depot) overhauling and calibrating meters similar to this one. The jewel bearings used to come in an applicator that released one at a time and were tiny.
Anyway, enjoyed the video 👍
More of them, Dave. That was a good one.
I always wandered about these meters ,and didnt found a good explanation until now, still they have a lot of mysteries to reveal ,thanks
Very cool Dave- Analog is good for the soul.
The holes in the disc are for testing, a laser is passed through the disk and you'll get a test pulse every time the laser passes through that hole. In the states, we perform three tests on meter. A full load test, a light load test, and a power factor test. Adjustments are made to the magnet in order to speed up and slow down the disc to calibrate the meter.
Ah yes, our old meter. When we got a quote to get a smart meter (which I was able to hack - good old software backdoors), the engineer said “Jesus, you didn’t tell me it was an old analog meter you had!”. That meter was installed when mainstream electricity first became available in our region and it had never been changed since then. We’ve still got that meter (not connected to mains, we’ve got it in a custom acrylic display case because of its history) because I love anything electrical and old/vintage.
Nothing like seeing a really old meter on a building.
Yes, it is amazing! Plus these things must be engineered for reliability and consistency over a few years or even decades, as it would be so damn impractical to cut off the power in order to swap the meter every year or two. I like the meter-base interface used in Australia - it allows for a very quick replacement (even without cutting the voltage off), way quicker than European meters, because they have screw terminals on the bottom side, covered with a plate that is sealed to prevent tampering. Oh, and retarding the meters with neodymium magnets was an energy companies' nightmare to the point that they really welcomed the modern electronic meters...
By the way, I wonder how a double-tariff electromechanical meter works.
if i had to design one: a small motor that drives a reduction gear such that it rotates at 1rev/day. and an extrusion on on half on the top side of the gear and bottom on on the other half of the gear. the extrusions actuate switches that connect either one or the other meter disc driving mechanism to the circuit.
We have similar meter mounts in North America, except ours have four or five tabs because of our wacky split-voltage system.
Regarding double meters, I think they superimposed signals on the power line to switch between the two modes. My guess for the actual metering part is that the current coils on each meter would be in series and they would switch the voltage coils on and off to determine which meter spins.
double tariff mechanical watt meter works in conjuction with relay switch. Every day in same time (im my case at 9PM and 7AM) electromotor with generator starts in my local substation. When generator is spinning it produces 1060Hz ripple and send it to electric grid for few minutes. Mine relayed switch "hears" that ripple and switches tariff mode on watt meter. After few minutes generator disconects from grid and shuts down. It starts again when is time for another tariff change... Generator works on very accurate substation internal clock and everthing is relay powered there, very simple and robust. System works so good that mine electricity company dosn't follow seasonal hour change. During winter hours cheap tariff is from 9PM to 7AM, and during summer time cheap is from 10PM to 8AM. substations internal clock is never changed, so company save a lot of money on maintenance because God knows how many substation and clock and generator systems they have. They just move tarifs + - 1 hour and don't change anything in their system
@@lordred7462 That motor generator system is called the Zellweger ripple system, used for tariff control, load shedding hotwater circuits, streetlights etc. In Auckland it is 1050 Hertz.
@@lordred7462 Depends on the technology your distributor chooses to use. ETSA (for instance) used a mechanical time switch rather than ripple control.
Hey Dave, you actually don’t even have to disassemble the unit to pull it out of the receptacle. There’s a puller tool linemen use to pull it out as these things need replaced often enough to warrant it.
What you could do is make a small diameter hole through the plastic casing with a dentist drill or heated wire, place a small metal rod through that makes contact with the disc and slow it down that way. Just remember to remove it before they come to measure it and do not to get too greedy. For good measure, cover the meter in some dust so the whole is less visible ;)
That multimeter has your logo on it (6:49) - OMG! THumbs up.
Used to be called buzz boxes here, a small transformer that was wired across the meter to slow or reverse the disc, many of the later meters had flags that popped out if the disc rotated in reverse as a visual display
This was really neat Dave! I have always been curious how those analog meters worked!
It's interesting, how good it is for measuring low-pfc (in terms of current shape, not a passive power) units, like some LED bulbs. Some modern (electronic) units exhibits "gigantic" error here, as it was shown in one article (authors were from netherlands, afair).
'Some modern (electronic) units exhibits "gigantic" error here' Got any more info or a link for that? Sounds interesting
@@nicwilson89 search for article "Static energy meter errors caused by conducted electromagnetic interference"
I think they would pretty good with accurately measuring power on abnormal current waveforms. It's abnormal _voltage_ waveforms I would be more concerned about.
@@eDoc2020 But a current is a problem here, as voltage is usually well-shaped...
I love your Friendly nature 😊 Keep up the vids good sir!!!
Thank you for the in-depth review!
I have one with an indoor socket that the power company left in my grandmas basement in the 90s. I wired it up for use on 120v and still works.
4:12 Why do the two magnetic fields (V * I) multiply together rather than add? The explanation later (5:16 and then later in the video) only explained about how the phase difference models the power factor, but not why the two fields multiply together to give us power V*I rather than adding V+I
omhs law! .. P = V*I
theres no such thing as V+I ..
@@WacKEDmaN No, that doesn't answer my question. I know that P = V*I. But in the video he said that the device calculates V*I. But why would having two magnetic fields overlapping multiply the fields? Shouldn't it add the fields instead? Looking for an explanation of why the device somehow calculates the multiple of V and I rather than summing them, so that it can compute the power correctly.
The physics of combining magnetic flux components results in a vector dot product, not a sum.
@@RichardKinch Right, but why? It seems counter-intuitive. Know any good explanations of the physics?
@@lurkertech Cf Maxwell's equations
My dad was a electro mechanical engineer and I studied industrial electronics. And every thing I learned about they had a mechanical equivalent.
So much more to them than you would think.
Here in Russia we had quite different design of watt-hours itself but its discs has that stamped square dots too. It's definitely not a voluntarism of designers. I think they're works quite similar to how slits on unipolar machines discs works. Like optimizing paths of indused current.
By the way, one of the most popular riddles today. Why does a unipolar machine generate exactly the same voltage if a round magnet rotates with its disk, as when the disk rotates, but the magnet does not.
@Liam but by the induction law it must be!) So this way when a magnet rotates along with a disc, EMF must not be generated but it does.
Years ago in the US, we learned "ELI the ICE man". E-L-I (Inductors 'L' voltage 'E' before current 'I') and I-C-E ('I' before 'E' in capacitors). :)
The case is probably polycarbonate vs. acrylic.
At a trade show in Chicago around 1975 GE Plastics had a demonstration of the durability of Lexan (polycarbonate). The demonstration consisted of a power meter cover, similar to the one in the video, and a standard 10 pound sledge hammer on about a 12 foot shaft. The top of the shaft was hinged. When a rest vertically the sledge hammer just touched the Lexan meter case. The sledge hammer was raised to horizontal and released to hit the meter case. You could see the Lexan case deform by a couple of inches or so and the demo repeated several times an hour. GE Plastics made their point.
A thing of beauty and not remotely hackable - unlike "advanced" "smart" meters.
It also can't "decide" what temp it will allow your heating/cooling to run at.
This degree of remote control is reported as being done with "smart (arsed)" meters overseas.
Might be a good topic for a few vids :)
Love your channels, Dave - Happy New year!
I noticed they arranged the contacts so that you can only mount the meter in the correct direction. Here in the US we have center tapped neutral on 220 V, since the top and bottom are basically two hot legs the meter has to handle two hot legs( I cant remember if the neutral is connected to the meter.) You can turn the meter upside down and plug it back in and the meter will count backwards, so you HAVE to have the meter tamper locked.
The power company swapped out the old school meter about 8 years ago and I have to say I found the old ones a LOT easier to read. I use an electric lawn mower and it was cool to stand next to it, turn on the mower and watch the wheel go crazy. Now I don't understand the output of the digital meter at all, nor can I see the reaction with the lawn mower. But, I guess it keeps a meter reader out of the back yard every month. I loved the teardown, I understand most of it, though I never studied AC circuits so the interaction between the volt induced eddy currents and the current induced eddy currents is still not fully understood, but I do delight in the elegant engineering the device presents.
You must have a completely different kind of digital meter then. Here in North America they have an LCD which directly displays the kWh count. Definitely easier than the counter-rotating hands we needed to deal with before then.
You would love some old electric grid protection relays. All mechanical relays that protect lines, buses, transformers, etc. Distance, differential, over current and more. Many are still in service and still accurate to +-5%. Very similar to mechanical meters except for 50x more stuff packet into one.
Decades ago, when I was much younger, I tried to see if I could get that disc to spin fast enough to break the sound barrier. Unfortunately the only thing that broke the sound barrier was my father's temper, after seeing the electric bill that month. 😁 ⚡️
I made a desk lamp that has an early 1900s meter (beautiful brass components) as it's main feature.
The box and plug design on these meters in the U.S. is a bit different. The way they are built it is physically possible to turn the meter upside down in the housing, which will make the meter run backwards (illegal, of course.)
My favorite line was the part about the steady eddy current. :)
It was truly fascinating to watch you take it apart.
Could the dimples be there to reduce drag in the air flow, like on a golf ball?
The dimples on a golf ball work to induce turbulent air flow, which at the speeds and spins seen in golf balls, will increase range and shot repeatability. If the disk was spinning quickly enough to induce turbulence in the air on its surface, the whole device would probably tear itself apart. Also they probably wouldn't need to bother with the permanent magnet to stop the disk continuously accelerating as they'd just have designed it so air resistance would do the job.
Ameran wanted to replace analog watt meter for a digital one. I refused. They now tack on a $20 a month penalty fee. I refused because when my mother allowed it on hers, her monthly bill increased substantially.
I love how much stuff been thought for these meters :3
Swiss precision design and manufacturing! Landis & Gyr is a Swiss Company, but they where bought by Siemens a few years ago ☹️
Great video Dave!
Interesting, an *anti* creep hole!
Most holes attract creeps.
Lol 😂
Awww…I was expecting you to test the accuracy of that meter. See if it was ripping people off in its past life. 😯
In Serbia, one guy made a very small hole on the glass and put some dead bugs on to the disc, which made it jam little bit and turn slower 😎 they couldn't prove it was his fault as he was passing much less than he was suppose to 😂
Hmmm..holes don't usually appear in glass and I'm not aware of any bugs that can chew through glass. Couldn't have been inspected very well.
@@daic7274 well, they couldn't prove that it was his intentional damage 😂 so he got away with it.
Hmm I guess you could simulate something that looked like a rock that was shot out of a lawn mower or something to impact the glass. A small rock and a slingshot would be the way to go.
yes, nice you can stop it or spin it with the magnet, I found some damaged one that kept running with no load without stopping, some with mechanical damage due to resonance caused from harmonics or from people with magnets playing around. in some probes, north side of the city they spin faster with no load, the south side of the city, the same meter spin slower with no load. The new ones can even document the reactive power.