Inside a cheap eBay motor-start module.
ฝัง
- เผยแพร่เมื่อ 26 พ.ย. 2019
- This is really neat. It's a mass produced module for use in fridges and freezers that controls the duration of the start winding current when the compressor starts.
Traditionally the same task would have been done by a current operated switch that would close with the high initial current of the stationary motor and then drop out once the motor was running and the current dropped, but this method achieves the same results in a cheap, simple way with no moving parts.
Here's how it works. It goes in series with the start winding of the motor, which is usually only energised briefly at startup. When power is applied the device appears as a low resistance allowing current to flow through the start winding. The current causes the PTC element to heat up and its resistance rises, which means it dissipates more power, gets hotter and this behaviour results in a sudden increase in resistance until the only current that is passing is the amount required to maintain it at its holding temperature.
When the power to the motor goes off the PTC cools down and returns to its low resistance state.
The thermal effect means that the PTC module will take about a minute to recover to its starting resistance, but in a fridge or freezer the time between compressor cycles is long enough to allow a full reset.
The trip time will depend on the modules initial resistance, starting temperature and the load current passing through it. With a 100W lamp on 240V the current was low enough to take about 90 seconds to final reach its trigger temperature. With very low currents the unit might never trip. This opens up the interesting possibility of wiring one in series with a light fitting so it could only be used with low power lamps.
There are probably many other uses where a suitable load could be protected from long run times or overload. That could be to protect a high power solenoid or other coil, or to protect a motor from a stalled condition.
Best thing is that because they are a mass produced item they are very cheap on eBay in a range of different start resistances. Common resistance values seem to be 4.7, 12, 15, 22 and 33 ohm. I'd guess lower resistances are for higher power loads. There are also a few case styles and pin numbers. I'd recommend the 2 or 3 pin units for ease of connection. Note that an unused pin will probably be connected to the other on the same side and should be covered if not used.
www.ebay.com/sch/i.html?_from...
Also keep in mind that these should be regarded with the same mild suspicion applied to all cheap eBay components.
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:-
www.bigclive.com/coffee.htm
This also keeps the channel independent of TH-cam's advertising algorithms allowing it to be a bit more dangerous and naughty. - วิทยาศาสตร์และเทคโนโลยี
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I learned two things watching this video... That Clive is an awesome teacher... And that Clive has well manicured hands... Wow...
Never mind the module, havent seen those mushroom bulbs in ages! 😂 very nostalgic clive. Lol
BONUS; demonstrates start capacitor very nicely. even I understood why the are 4 cores in the lead of my submersible pump. Thanks Clive.
This should be mandatory viewing for anybody making silent air compressors out of fridge compressors, probably one of best explanations of how PTCs work.
Most people will recognise the effect of the ptc thermistor from their old CRT TVs. The memorable switch on Twaaaaaang which was the degaussing coil wrapped round the screen envelope in series with a ptc device and the mains. A very effective use. The magnetic field would be large at switch on with large current flow and the alternating field would demagnetize the shadow mask. Then it would drop the current away in four or five seconds making a perfect diminishing ac field to ensure it does the job.
*_BOoOoOoOoOoOoOoOoOoOoOoOoOoOoNG_*
The old computer monitors I used to install used a relay to switch the degaussing coil on and off. You could hear it click in and out again after a few seconds and there was usually a manual override so you could give it a damn good degauss if it was necessary.
@@jamesharmer9293 It was common with smaller portable screens to have a manual degauss as moving them about could upset the purity. Never seen one with a relay though.
@@martinda7446 I used to install lots of 15 inch computer monitors and the degaussing was quite important. What got annoying though was when the magnetic fields of a bunch of monitors would all interfere with each other. They used to shimmer like crazy. I once saw a guy with 16 screens on his desk, though 4 or 5 was more normal.
@@jamesharmer9293 Ha, ha, ha I can see it in my mind...Like a crazy GIF. That's a great image.
This is absolutely one of the best channels on all of TH-cam.
True.
Agreed.
Yep.
And the "Long Nose Pliers of Additional Enlightenment" have made an appearance!!
I grew up with the "Klix-On" and got thrown for a loop when these first came out. Thanks for the vid.
Yeah, when you get a power flicker you don't have to wait for the current draw relay(klix-on) to cool down.
Interesting to see you dissect one of these. I frequently have power fluctuations since my local power company can't keep the rural area I live in maintained properly.
During a recent storm, the power kept cutting on and off quickly. Afterwards, my refrigerator stopped cooling.
After some research, this was the defective part. It was an easy replacement, but I unfortunately decided to buy the part made by the manufacturer, because I didn't want to take a chance on a knockoff. It is almost the exact same device but it cost me about $70 from a part supplier in the next town.
In the future, I will probably buy a cheap one and hack it onto the compressor. The one I installed had three holes that plug directly onto three pins of the compressor.
I was glad I didn't have to buy a new refrigerator, because I had assumed the compressor failed. Still, the name brand part should be much much cheaper!
Here in California we have power cycles too...except our power stays off for several days between cycles.
But I bet you save on your power bill that way!
@@tncorgi92 but not enough savings to keep replacing all the food in your refrigerator.
Yes, because US power lines are poorly maintained, unsafe ugly mess. Lots of videos on TH-cam of US power lines on fire and/or arcing/sparking - some caused by trees that should have already been cut back or cut down. Hardly any videos of european powerlines arcing/sparking - certainly no exploding transformers.
3rd world countries usually do.
@@simontay4851 I cannot comment on the state of US power lines but I believe the situation in California is due to PG&E and other Cal utilities cutting power to prevent the spread of wildfires due to electrical distribution equipment.
I love watching your videos while eating. Just wanted to say thank you for your work.
Literally just bought one of these for my mini fridge and then you published a video about it the day after!
A very similar device was used on old TV sets to run the CRT degaussing coil for a few seconds after powering the set on.
You beat me to it. The devices had 2 PTC elements in them in thermal contact, one was in series with the degausing coil, the other was across the supply. This meant that the heating from the PTC across the supply effectively kept the PTC in series with the degausing coil hot, thus reducing the current flow through the degausing coil to almost zero.
Boioioiingggg! ah, the good old 17" crts, which could run up to 75hz instead of the spec 60hz..
and the cheapo unshielded speakers.
I would love to see Clive make a degausser.
I've featured a degausser in a video.
Fancy meeting you here! :)
I've used them to limit the inrush current to a projector bulb. You can put them in parallel or series to get different current and time constants. You can snap them in half and solder to the sides to get higher resistance ones.
Cool! Seen many of these on your channel, but don't actually know the composition that makes these operate. Seems odd that a ceramic disk can pass any current. 🤔 Off to Google I go to find out!
Edit: So these are ceramic doped with barium titanate. At the Curie point, they just stop conducting, although at high enough temps it becomes a NTC again, like when they're cold.
They also have silicon versions, (silistor) which have a linear cutoff voltage dependent on temp rather than a quick one like the ceramic ones.
There's also polymer ones, which I think is fascinating. It's a plastic containing lots of tiny grains of carbon. At lower temps the carbon grains contact each other and close the circuit, but when heated up, the polymer expands which moves the carbon grains apart and opens the circuit. Awesome!
The polymer ones I have seen and used on electronics projects as resettable fuses ("polyfuses"). Apparently when they go open, they stay that way for a longer time than it takes for them to cool down. I imagine the physical changes you describe are linked to that.
Technology Connections video sent me to this video in 2023. 👍
I did see he'd just covered a fridge/freezer.
The holes in the back are for installing it directly onto the pins of the fridge compressor. I replace these all the time to fix broken mini fridges.
Yep there are three pins on the compressor, that starter relay fits onto 2 of them (start & run) & the thermal cutout (called a klixon) is connected to the third prong (common).
You fix mini fridges? I have a question for you in the morning! :o)
@Sassy The Sasquatch riiiiiight...
@
Stephen Kasprzyk, you probably have to put caps on the pins in that case, right?
@@rolfs2165 Unless the electrical supply is through them ?
These superseded the mechanical starter relays in refrigeration about 30 years ago; no moving parts = much higher reliability.
Is there anything Clyde cannot explain in a way that even a novice person like myself cannot understand. Another informative and entertaining video by a real Master. Thank you so much for all the great videos you have put on TH-cam.
I think you are the only TH-camr shooting videos at 10 degrees inside ambient temperature ;)
I wish that I was as comfortable at those temperatures as Clive is. I could save a fortune in winter. Mind you I'm guessing the downside is discomfort at higher temps and I live in NZ so six of one...
Interesting how it's rated at 22 ohms but Clive's place is so cold it drops back to 18 ohms.
Yeah these things are usually rated at 20 degrees C.
The correct term for this device is "positive-thermal-coefficient thermistor". It's basically a block of resistance material that conducts heavily when cold (this inserting capacitive current from a motor-starting cap into the motor) but becomes high-resistance when it gets hot (which it does after about 2 seconds of operation), thus cutting-out most of the capacitive current once the motor is running.
I had to replace one of these on my fridge about 8 months ago. It died and the compressor stopped running. On opening it up, it had a block of resistance material which was shattered into about 5 pieces. So I went to an appliance-parts shop and bought a replacement kit with both a ptc thermistor and a temp sensor, and replaced both, after which my fridge operated normally again.
This terminals are designed to mate with the standard three pin, hermetic sealed, feed through normally seen on small refrigeration compressors. Pre PTC days the compressor used a current relay wired with the operating coil in series with the run winding. On start up the high current draw would close the contacts on the current relay and feed power to the start windings. When the current in the run windings dropped the relay would drop off and the start winding would be disconnected. All the ones I ever came across were manufactured but a company called Klixon. The only time I ever saw a failed one was from where the start winding had failed so the current relay had stayed on and got black and crispy. Compressor checks were always pretty straight forward, the run winding is normal about twice the resistance of the start winding. Repairing it after was a job is hand over to the Refrigeration Engineer; I didn't work on enough refrigeration kit to justify the expense of more tools (and refrigeration tools are pretty costly)
Love it. Thanks Big Clive. What a cool device. Thanks for going through the various applications and so on.
Another better understanding of Things for sure.
Just love the KISS principle at work here. 👍
13:32 Those "springy contacts" are for the connections to the motor windings, the flat spade connectors are for the powersupply.
This motor-start module is the modern version, the older version use a sort of relay, where the coil gets energized at startup, during the off position, the contacts are bypassed, and pass current to the start winding, but when the motor starts spinning, the plunjer of the coil gets retracted and the contacts go open and cut off the current to the start winding.
12:17 that moment when Clive makes the overload circuit look like an upset face.
For most modern refrigerators that use the type of motor that is designed for it needs 2 more spade connectors for a run capacitor. To increase the efficiency by about 2/5's lower amps. They will run for a while but will over amp the run windings in the compressor.
Available now is the capacitor start(never a bad thing) capacitor run unit that comes with a 12 mfd cap. which is the most common. But you can attach the original cap. if it is of a different value. The motor is designed to run with that particular mfd cap for maximum efficiency, and they only very rarely fail. Like almost never.
'Supco' brand components and it's called a 4-n1 start relay. Very useful. Definitely NOT the '3-n-1' which doesn't have the crucial run cap. connections available. I have replaced many compressors that were ruined by this misapplication.
I would like to see a video on the electronic type of relay- for instance Whirlpool brand part number w10189190. It has an interesting little board and stuff in there and B.C. could go to town on it.👍
Oooooh, I love these tear downs 😍😍
Excellent technical vlog.
Thanks for sharing.
I have used the opposite device, an NTC thermistor that drops in resistance as it heats, to start DC motors that were powered by a current limited power supply. DC motors draw a large inrush current when first starting up. This can sometimes be enough to blow fuses or trip out switch mode power supplies that can otherwise handle the motor current once it is up to speed. Using an NTC rated slightly above the running amperage of the motor provides a nice soft start. If you use a heavily overrated NTC the motor will never come up to full speed.
These thermistors do get hot though. You will want to keep them away from melty things and fingers when in use. For large DC motors, air conditioner blowers on busses, I would use a separate timer relay to carry current past the NTC once the motor was up to speed (1-1.5 seconds) simply to allow the thermistor to remain cool once everything was running properly.
Had to replace entire a/c unit on my house about a year ago. Frequent Power Loss is my power supplier. When installing the condenser/compressor (the outside unit) I spent $20 on a delay switch. When power loss occurs the switch cuts the power for 5 min. We have a real problem with the power blinking out for a few seconds then popping back on and blowing again, which obviously isn't so good for things like motors. When we get these cycles often u can hear the neighbors a/c units just humming away until it overheats and resets. I'll deal w not having a/c for 5 min rather than setting the fans and compressor to the broil position. Also if ur having ur unit worked on it pays to buy an extra capacitor. Caps don't like hot climates very much and are basically a consumable item. Having the right one on hand can save u hours or days of discomfort and a hefty bill from a repair company.
Your absolutely right with the old 3 shot and 5 shot pole mounted auto reclosers. Things have moved on considerably now, most pole mounted 'active' equipment are radio controlled, as well have a certain amount of local decision making based on fault current and such like. These radio controlled units open and close via computer systems having a more overall viewpoint of any faults, and subsequently narrow the fault down to just the point of failure. Areas where overhead lines are used do benefit from regular tree cutting mind.
Quite interesting video from a quite ordinary looking component from ebay. Great job 😀
It has been said that incandescent lamps do not appreciably strobe. Well, they do strobe enough to cause a 100 (or 120) Hz hum when operating an exciter bulb in a film projector, even with fairly good rectification and filtering. The LED and laser based red exciter assemblies that were introduced in the mid-noughties (accompanied by cyan dye in the soundtrack instead of black) did improve the hum problem because they actually had regulation. Although, digitalization was dawning already in 2004 when the first producers started making their prints with the cyan dye. And it was gaining good speed already in 2010. My theory is that although it was said the extra black dye used in the soundtracks would release toxic products into the atmosphere when burned, the truth behind all this was that the red light/cyan dye technology had to be sold somewhere in a rush, AND because the change would cost up to 10k EUR per machine, there would be cinemas that would not be able to swallow the pill. Truly, many went out of business because the distributors would no longer supply prints to cinemas without the new red exciters. A friend of mine got a few more prints when he lied to the distributors about the status of his cinema, and he would just ramp the volume up a few notches (although there would be a lot more noise). Once all distributors started requiring a certificate of the red exciter installation from a licensed contractor, no more luck. 2006 was the last year before an oncoming municipal merger, and our municipality would no longer grant support for the cinema. So out of business he went. And, to be frank (which I am not) I think all this was done to kill off "a few" booths so they wouldn't be queued for digitalization. There really was no true need to get rid of a potentially toxic component that had been used for decades, just to get by a few years. There would still be more cinemas that could not afford to digitalize. Now it is about ten years from the last foreign movie that was distributed here on film, and a wee bit less from the last domestic one.
My fridge has a 10uF AC start cap in it and the compressor has a thermal cutout device on it. A fridge compressor under load (high head pressure) cam draw more than 15 amps on startup on a 120 VAC supply. This depends on the size of your fridge of course. A window or RV rooftop AC unit can draw nearly 30 amps (on 120 VAC line) under load at startup and you homes central AC unit outside can draw over 100 amps on a 240 VAC line under load at startup.
The #1 failure in home AC units is a capacitor on the air handler / fan or compressor. next would be the units contactor relay an / or 24VAC transformer
Sump Pumps, Sewage Pumps or (really big versions of this) electric Cargo Ship motors (MANY Years ago, my high school class took a field trip to Conestoga College in Waterloo Ontario and at the time, they had a motor who's Rotor was 50 FEET in diameter. It was designed to turn one of the 2 propellers that drove a Supertanker through the water...they couldn't start the thing because if they tried, they would have caused a Brown-Out for all of Waterloo County...)
I have a trio of these in a drawer somewhere, a Haier mini-freezer I salvaged a few years back decided one day to stop running (after I'd tested it, cleaned it out and moved it indoors from my shed!!) and I tried replacing this doodad to no avail (probably seized piston, annoyingly), they just plug straight onto the compressor via those L & N holes once you've connected the wires to it, quite simple things really... :)
The good thing about that type of "relay" is you don't need a meter to check it. If it rattles when you shake it, replace it.
loved the Department of Villainy project .
I want to clarify things a bit. The compressor needs to turn a few times to start so freeing the preasure just in the cylinder its not enough for it to start. On all shop compressors there is not not one but two one way valves. One is right in the head of the compresser and the other is at the end of the pipe that goes from the compresser to the tank. That hissing sound is made by a third valve that is built inside the presure switches and is releasing the preasure in the pice of pipe between those two one way valves.
Neat little device. Every compressor I've ever seen be it household or shop had a big starting capacitor. Have one in my drawer that you can't even touch your fingertips around it from a particular beefy motor. Only other things I've seen on the motor side of the circuits are thermistors between the start cap and motor (as in physically sandwiched).
Hi again Clive, they are designed as a push fit onto the thin round contacts that stick out of a hermetically sealed compressor. I think they have a flat springy metal strip over the top of the unit to keep it in place.
I love this channel.
I have never been a fan of PTC start winding control. I prefer either centrifugal *internal in split phase motors which is common on air compressors, bench grinders and traditional central ac* or electromagnetic potential relay to control the start winding *common in US refrigerators*
9$ for me and it fixed my wine fridge 10/10 saved it from the endless trash heap at the dump.
thats kind of cool in a safety perspective and quite cheap
Best compressor impression ever ,
I'm amazed that the price was so low. A couple years back, the PTC disk on my fridge disintegrated from age, and the appliance repair shop wanted something like $70-$80 for a replacement. Fortunately, there was another shop with an old pro who handed me a module which he had salvaged from an old unit, and I was able to adapt it.
Until I was able to make the repairs, (in order to save my food) I was forced to manually start the compressor using, shall we say, a suboptimal restart procedure.
One of these went bad on my parents old sub zero fridge freezer. I just bypassed the thing and the fridge continued to work for years more. I knew it did something, but wasn’t sure what. Interesting. 😄
Wow, mine just went out and I just got my controller and protection in the mail! What timing! Cheers 🍻
I fixed recycled fridges and freezers about a decade ago. There were older PTC's, molded on white plastic casing and newer black ones, which were more durable. Fault, which was easy to spot. The customers sometimes called, that their fridge/freezer was sold broken. First question: "Did it smell bad?". If yes, "Did you carry it sideways, and didn't let the oil settle to the bottom before starting it", and if no, "Did you bring it from the below zero temperatures straight in and started it?" (altough i already knew the real answer).
I have seen that hopi meter 1000 times here but, this is the first time I am realizing it says "FREQUENCE" on it. :-)
PTC's were used in old CRT displays to drive the degausing coil at switch on, if you ever heard a him and saw the screen wobble when turning on a TV that was the degausing coil. Also 11:19 "Compressed liquid" you cant compress liquids (which is why you need to leave fridges/freezers a while after moving them to ensure there is no liquid in the compressor as that will damage/break it. The MOD had an issue with the compressors on drinking water coolers in tanks blowing up because of this. A friend designed an upgrade that helped prevent this).
Good example of this type of unit also used in automotive door window motors they went bad and one had fun trying to close the Window.
Slippery slope as next you'll be looking into current relays and potential relays which are used to cut out the start windings on some motors. You can buy a hard-start kit to put on a PSC motor that is just a capacitor, PTC and thermal switch.
Nice to see how this module is supposed to look like from the inside. Mine did burst into flames recently and melted the whole junction box of the fridge.
I think old crt televisions used to use a similar ceramic disc thermistor to control the degaussing coil when you switched the tv on.
CRT degaussing coils used varistors in series on every power up to taper off the drive current hence diminish the alternating magnetic field to zero over a few seconds. This resulted in a demagnetised screen mask and you could usually hear the hum they made when you switched the screen on.
It works as a degaussing thermistor in the CRT type TVs.
It would allow enough current to flow for appx 10 seconds then go high and shut the degaussing coil.
i sense great mischief possibilities, such as someone trying to work out why a device runs for seemingly random amounts of time and sometimes comes on and sometimes refuses ¬_¬
mm HVACR parts my favorite.. Start capacitor +momentary switch+ mains directly to start cap= smiles and debris
People need to know about these, I fixed 3 fridges just this year for a few dollars that would have ended up in a landfill
Run and start capacitors are used when medium & high back pressure conditions exist like a TXV that does not allow the system to equalize.
Clive if you’re ever in Texas come find me. You can upgrade old factory control equipment all day with us then we’ll go drinking after
1:46 Whenever @bigclivedotcom plugs in the Hopi, he mentions the flickering! 😄👌
The internals of that look identical to the Degauusing PTC's that old skool CRT's used to have. They would ensure a nice big chunk of electricity went through the degaussing coil (which demagnetised the CRT) on startup and then dropped to near zero once the deed was done and the PTC warmed up...
The little vent thing on an ordinary compressor is called an UNLOADER VALVE
i only know it as a bleeder valve
Well done.
Your small disc ones were used in old tube type tv's to energize the degaussing coils when the set first started up.
So I found your video on that component I was after here.
Half the fun is getting stuff apart!
Those things are also used in old crt tv's and crt monitors.
10 Celsius - you're a hardy man - I'm imagining you in a mad woolly hat
Come to his next live stream to check if your guess is correct. ;D
He's Scottish. He's never cold.
Where we live (South Coast NSW) the winter temps don't drop much below 10C overnight. I really couldn't cope with that cold, this early in the winter (not quite December yet!) We do get hot in our summers, but we'd both rather be hot than freezing (and for the Wife, 10C is definitely her idea of "freezing cold"!) :-)
@@phils4634 Lol, 10 C is like t-shirt weather. 15+ is shorts :D
@@han5vk I you're wearing shorts when it's 15C, you'll have a great time when it gets to 45C (a "not un-typical" summer temperature here!) Even our pool is "bathwater warm" which is not that great when you are hoping to cool off a little! :-D It can get so bad here that we clamber out of the pool and nip indoors (A/C, so cooler, drier air) just to briefly "enjoy" the evaporative cooling!
PLEASE _ PLEASE _ PLEASE. Hi Clive.Sorry this is off topic. My Tamil, Hindi, etc., is not too good these days and I cannot find any English explanation about the different types and sizes of SMD capacitors on TH-cam. On the Net what I can find is for those that already know the subject. I do appreciate you are not heavily into SMD components but you did OK on that DIY solar garden light. I won't blame you if you ignore this plea, I'll just wander out alone into the dark, wet cold night and stick two fingers up the local substation and come and haunt you.
My (bigger) air compressors have mechanical "unloader valves," which sense the reduced pressure in the output line (when the motor stops), to dump the pressure inside the cylinder. These particular ones give a distinctive "klang" when they operate, which covers up the "hiss." No electricity required.
The hole for compressor you directly mount on to compressor pins
You know, I have worked with these all the time, but this is the first time I have seen what is inside of them. If you want another interesting component you should dig into a potential relay that uses feedback to cut off the start capacitor from the circuit so it doesnt.. you know.. overcharge and blow up.
Happy Thanksgiving everybody.
In former times they used such a device for powering the demagnetisation coil at the front of the screen of a colour TV tube removing the remanence of the invar mask upon each powering up of the TV set.
Thank you BC!
The pin holes with the springs inside are designed to clip directly onto the pins sticking out of the side of the compressor.
Clive, with Christmas coming up, is there any chance that you could do a review of beginners electronic maker kits (including your own of course)? I'm wanting to get one for my 13yr old son. It'll be his first foray into it, but he's keen to get soldering rather than play with a clip together kids set. Thanks!
Buy a medley of cheap Chinese LED flashing kits (suites). They represent good value and are excellent for practice with visual results.
is there an age limit? because my kid is only 0.66(cont) years old and cant hold a plastic sword, let alone a iron yet!
Dave EEVblog does some heart warming videos building stuff with his young son. th-cam.com/video/lamL392NJRM/w-d-xo.html
Oh I can think of loads of wind-ups you do do with that thing..put in series with stuff that would just fail hahaha!
Awesome 👍
Everlasting Horlicks tablet. (Only for Brits of a certain age)
Do they still do them ?
I miss them. Haven't seen them in years.
For non brits: Horlicks is a milk additive powder mostly containng malt. Growing adult however, they prefer malt in the form of bitter, lager, or whisky.
@Sassy The Sasquatch Ovaltine (aka Ovomaltine) has a much different - Swiss - flavour. Where Horlicks is more yellowish white, Ovomaltine is brown like a chocolate drink.
Only available in chemists back in the day, not sure why. Are they still made?
Also, the powered windows on my car probably use these as there's no limit switch . The windows are disabled when the ignition switch is off, so no unwanted battery drain.
Interesting fact: Climate change changes the behaviour of this device, it will get quicker to it's threshold temperature. I think the refrigerators of the globe are not changing their behaviour, because the time until switching is used to start the motor. As this time can vary, there must be a safety margin in the delay. If the switching occurs earlier, that will be much smaller than the safety margin, and just eat a tiny fraction of it away.
Klicksons, high and low sides dryers and receivers ETC and as Clive likes orifices. Yeah i have also done the industrial fridgie stuff too and also made my own contactor panels up too 1, 2 and 3 phases (230,380 & 440V) and star/delta starting. me and you have similar pasts 😉 ho i forgot short cycling lol
If Clive made a clip about the Second Law of thermodynamics i'd definitely be interested in watching and possibly learn a lot more about it than i did in school! B.T.W Clive ever considered a career in teaching? Then again in a way through TH-cam.
Similar ptc's are used in hot glue guns too (as I'm sure you know), where their self heating melts the glue, and their resistance increase limits power and temperature.
how long has this been a thing? because every glue gun i've opened since i was born in the 80s has been a coil of resistance wire like a soldering iron, i know they exist because i've watched clive take the apart
@@frogz I'm really not sure, I've only taken one apart, and was surprised it didn't have a coil and thermostat, just a slab of ceramic with the mains conductors pressed against it, wrapoed in kapton film and pressed against the cast metal tube that the gluestick goes into. I guess the one I took apart was between 5 and ten years old. (The ratcheting system had failed, so I thought I'd dissect it before binning it :))
I had one fail in my fridge and it was just over 6 years old, at first I thought it was the compressor because I could just hear a hum then the overload would cut out. fridge tech I spoke to said oh its a Whirlpool it will be ya compressor get a new fridge. I got one of these from a fridge at the junk yard to test the theory and its been running fine since. resistance of mine was like 400 Ohms and should have been like 15.
Speaking of cheap, Ford put these in the window and door-lock motors of my father's truck. Evidently, the 8-year-old Bangladeshi field hand they hired to do all of the electrical design on that 'vehicle' chose the wrong damn PTC element. Result: in the summer, your windows won't go down, and you can't lock or unlock the other door with the pushbuttons, either.
Hey Clive, I hate those POS's, if you ask me, they don't take the start winding out of the circuit soon enough, in order to be able to use small refrigerator, like a mini fridge, off of 500 or so watt power inverter, because of the excessively long start duration, and you know that cheap power inverters, can only handle the surge current for several Cycles.
After hurricane Katrina immersed my refrigerator and freezer, I found those ptc ceramic discs had disintegrated. So I merely removed them out of the casings, but they both continued to run anyway. How neat was that? Also, don't they use a similar circuit for heavy mercury vapor lamps?
Some newer fridges will also refuse to turn on the compressor for about 3 minutes because the compressor is computer-controlled.
Older motors had a centrifugally operated switch that did the same thing.
These thermals and the older current relays they replaced are mainly intended for hermetic sealed compressors, but sure you could use one on a open motor.
You should have shown the difference between this one and the relay type that uses the current of the run coil to switch the start coil. This type seems to protect the start capacitor if the motor doesn't run.
the pin female contacts on the back is to mount directly on to an HVAC Hermetic compressor
you could use one in a toaster oven to release the lever holding the bread down.
Once worked with someone who behaved in the same manner 😁. 👍 from me 🇬🇧.