I would say the reason they installed the DC motors, instead of a much cheaper 2 speed AC motor, was to have a much larger car capacity, and also to not have snatch on the car, probably because they expected to transport heavy delicate loads. Or the controller was mostly built for another order, that got cancelled, and this order was rush, so they used what was in stock controller wise, with only needing to do rope length and travelling cable runs, the rest already having passed factory test. Frame with 2 bays is way too big for the number of floor relays, likely this was originally for a 20 plus floor building, just got cut down for the 5 landing use. The Ward Leonard system is complex, but has the advantage of start torque being very controlled, so giving a nearly imperceptible start and stop, which in a big lift can be a good feature, and the high speed in between floors is ramped up and down smoothly. The large motor generator has both the voltage and the current varied by the smaller ones, the lower voltage excitation is applied to the field to slowly bring up the power, and then switches to a higher voltage at full run speed, and also the main hoist motor field is varied as well, changing the amount of power it can deliver to ramp smoothly up and down. Been a long time since I looked at them, but the 90VDC generator provides the shunt field for both the 130VDC unit and the 130VDC in turn provides the large generator and the hoist motor field, with the resistors being there to limit current flow, and thus field strength, and thus the power output of the motor, and thus how fast it will slew up or down in speed. Fixed resistors are there to ensure that the generators will not provide any output voltage with no field current, because of remnant magnetism, and thus keep them from operating any relays or drive when they are being shut off. There will be a transformer providing 48VAC, powering the button logic and lamps, that also operates the motor shut down logic after 5 minutes of inactivity, set using a sensitive coil relay, and a very large value electrolytic capacitor, that takes 3 minutes or so to discharge the capacitor below the coil hold voltage, and this operates the main motor contactor. Press any button and the motor generators will all spool up, and after the 90VDC has reached operate voltage, closing an enable relay, it will run the lift. When all calls are satisfied, the relay contacts that keeps the big capacitor, charged via a big fixed resistor to keep contact current low, will all be open, and the capacitor will slowly discharge. Time adjustment is crude, you add more capacitors in parallel, till you get the right time.
AC to DC Rotary Converters are used due in Power Cuts - Emergency The Lift can still go To the Closest floor Due the AC to DC Rotory Converter still has torque & Fly Wheel rotational energy. In a Emergency if someone Straw/ Wood ice cram stick Block Certain Relays ( Plus a Few 9V 'Dry' Batteries) You can Trigger the Gravity break to Release and have a one way slow going down to Ground floor
@@hi-tech-guy-1823 You release the brakes manually, and then wind the car up to the next floor, as the counterweight is calculated to be just slightly heavier than a full car. Needs 2 people anyway, one to turn the handwheel on the motor, and the other with a break release lever, turning the brake to the off position. Brake releaser keeps an eye on the selector, and stops it at the next floor up, and then you go open the door and release the people inside. Lose mains power and the control relays all immediately, within 2 cycles, drop all out, as they are fed from either a 24 or 48VDC or AC supply, from a transformer. Car will coast for around a tenth of a second, before the main brake fully engages, and abruptly stops it, normally with a rather massive jolt, even if the brake is engaging slowly. Only on modern inverter controlled lifts can you have a large enough DC bus capacitance that will power the controller, so that it can drive the inverter into an emergency brake mode, recovering energy into the main capacitor bank, and thus slow the car down with around 5 seconds of power, perhaps enough to be close to a floor, but with a lot less stress on the brakes and cabling. Then will hold it stopped till the main DC bus undervolts, and the doors fail safe to open position under spring tension, and the controller does a final write to non volatile memory about the mains fail, and position of car for logging. Main micro might be able to run for 20 seconds or more, so HMI inside the car will be active with emergency warning, and the emergency lighting, if it has been properly maintained, will be on allowing people inside to be less that terrified in the dark. Incidentally, the most common brake models I have seen either, like Schindler does, uses a 3 phase motor, running locked rotor, turning a small gear train that drives the brake pads out of lock against spring tension. Or they are the Otis/Express/Fiam ones, with a massive solenoid running off 130VDC at 3A, pulling the brake pads off the drum. Coupled as well to the retiring cam, similar drive arrangement, so you need a rather hefty battery bank to actuate it, a pack of 15 PP3 cells in series is not even going to make it move a little. Incidentally was working on an inverter drive, 5 full height cabinets, where 2 of them are reserved for main DC bus capacitors, around 100kJ of stored energy in them, and a cabinet on top, with 50A silicone cables, and some serious fan cooling, that connect the brake dump resistors in case the bank rises too high in voltage. Has a set of power on resistors as well, to keep the surge down on charging to something the 800A mains supply will be happy with. With 6 little 10kW motors, and a main 22kW motor, it is using some rather serious inverters, and it came with a quick install guide that is close to 1000 pages. Plus 3 engineers from all over the planet to oversee it. Google translate was useful, though they did learn a good few swear words in the time as well, and also got to see the wildlife as well, which they absolutely loved.
Also these machines were a large fixed cost, so 2 to ~3 floor commercial, and 2 to ~5 floor residential low-rise elevators were more rare. They didn't have the disability access laws we have today.
In Wellington New Zealand we had two pairs of these operating at the Bay Plaza Hotel and Central Park flats, they were only modernized in the 90’s Beautiful stuff to work on, calls were latched by magnetic car buttons that only released when the lift changed direction after serving all floors. The central telephone exchange had a pair of gearless very similar but had two generators on the one motor to power the machine, acceleration was done via a motorised resistor feeding a saturable reactor
It amazes me how much time, effort, knowledge and money must have gone into constructing this amazing machinery! I thought that the Schindler dynatron already were machinery beasts but the lift in this video really blew my mind! Thank you for the time and effort you put into those videos! It is exactly what these machines have deserved!
Thank you very much for this truly outstanding video with the very detailed animations and explanations! Dynator is now too an almost extinct system and I'm glad that you presented it to the world! As of the workings - I would have to study the schematics fror longer but what I would say as of now is that Dynator looks a lot like the predecessor of Transitronic, the later Schindler high-speed DC drive system. I have a theory: Transitronic too has the main motor's and generator's rotor windings directly coupled together with nothing in between (except the WG resistor here). The main motor and main generator of this system use a separate supply for the field winding, just as with Transitronic. Now here's the catch: How do you get the separate voltage? On newer Transitronic it was possible to generate this voltage directly from AC through rectifying because in this later are of time, strong enough semicondictuors were available. But back in the 50s and early 60s that was not yet the case, so an extra smaller generator was used - one that didn't need separate voltage for itself to work. That also is, how the actual Ward-Leonhard machine works: It is two DC generator on the same shaft together with one AC motor, the smaller generator generating the field voltage for the big one. Then resistors can be used in that smaller circuit to vary the field voltage of the big generator, thus varying the actual output voltage of the big generator with relatively small losses.
As a very new 1st year apprentice for a small lift company in the AUS, I love seeing old gems like this. I just wish more of these were kept, but as years progress it seems that we’re heading towards overly simple and bland affordability. Going off by some lifts I used to know, most of them get replaced after 15 years of use, yet these old lifts can last many years! With the proper maintenance/care.
Anything not absolutely trivial done in pure electro-mechanical logic will get pretty complicated really quick compared to TTL/CMOS logic on a PCB, which itself looks ridiculously complicated compared to more human-friendly C/C++ or higher-level language code for a micro-controller.
Indeed! Makes you think why they didn't just use an AC motor for a building with 5 landings, but this video wouldn't have been as interesting if it had been!
I worked as an elevator fitter and replaced many of these old systems with new microprocessor-controlled systems. Mostly with NewLift or Kollmorgen controllers in conjunction with Ziehl Abegg machines. In my opinion, Westinghouse had the most complex and largest control systems, especially when it came to group control systems. Who can still remember the tuning toothpicks in the control relays?
Ah, do you mean the DMR systems like this one...? th-cam.com/video/FVgDDEf57s0/w-d-xo.htmlsi=QbrIoGjavDAT54EH&t=440 I filmed one a long time ago (th-cam.com/video/hz7NvgZaoDM/w-d-xo.htmlsi=wT1iEnF0vb299nF5&t=141), would do anything to see another one working!
I had a basic understanding of elevators but nothing like this, I have entered a completely new world of “elevator technology”. From a novice standpoint I like the older mechanical/analog technology compared to the newer stuff. It’s like comparing a Steam locomotive to a Electric locomotive. Looks like I found a new channel to watch. Thank you for the great video
Love the old machines with Ward-Leonard sets. Of course it's complicated, bulky and inefficient by today's standards, but it's just too cool to watch. As far as I know, they're pretty reliable too. There are still some cable cars and ski lifts around with the same technology, among them is the peak aerial tramway at Kitzsteinhorn with the pretty tall tower. According to the lift operator, the original drive system has never been changed since 1966, when it was built, and it still runs flawlessly till this day.
As an engineer and elevator inspector, I loved these old machines with their motor-generators and "pinball" logic boards, alas most of them have been replaced with the very mundane roped-hydro type machines. Schindler was a good company to work with, nearly as good as Otis and Westinghouse.
When this system was installed in the 1960's it is obvious that Schindler were still using 1930's technology. By the end of the 50's, Express had developed a floor selector fitted into the control panel, and it was indexed up and down by solenoids trigged from the lift shaft. the manufacturing costs were negligible compared to what we see here, and the reliability breathtaking. Having worked on many Ward-Leonard systems, this appears to be lunacy in ot's day. Love it, though!
Till that shaft had excess play, and you could have the car miss a tappet slot, and bypass a floor. I was almost tempted to go into that shaft with a load of steel plates, and jack the shaft back to true, but instead we upgraded the controller to an Otis unit. Well 3, first one got blown by the trailing cable hooking up, and applying 230VAC to the 24VDC circuits, and so did the second one, for the same reason. 3 controllers, and 100m of heavy flat trailing cable later, plus some rather brutal work with a grinder, to remove the sharp edges of the car, and that last one worked perfectly. Plus Otis had underquoted badly, but held to the quote, though the price we paid just covered the cost of only the controller, not of any work, or cables, or tapes, or any of the other stuff needed. But they had held that contract for 30 years, so ate the cost. I do have a piece of cardboard box, crudely ripped off, and with a crude wiring alteration drawn on it, that is in the master drawing file, complete with a laminated cover, signed off by the local PR.Eng from Otis. I added one extra jumper, and moved one wire over, to fix an issue where the current in the retiring can, and the brake coil, was being passed through a single contact in a 3 phase breaker, the one used to break the safety circuit, and the third unused. 3A per coil ,and it would trip if you went full stroke, with no stops, twice in short order, as the 2 currents were 6A, and the breaker is 5A. Split so 2 contacts now had 3A each, and no tripping issue, and breaker was correct for the use.
This system was also manufactured in Hungary under license by Ganz-MÁVAG. There are not many left, they have been rebuilt. Even with the motor, only the fast side works with a frequency converter.
Ahh...I was filming a Schindler earlier and cracked the same joke, despite my dialogue being in German¹... 🙃 (¹ - I'm actually English and was filming one of my local lifts...But not having been abroad since before the pandemic and _really_ missing those lands I love 🇩🇪🇪🇸🇨🇵, I'm trying to take a break from íngles when I can! 😇)
Hi mrmatt, your content never disappoints! Although I’m still unable to understand everything given that I’m no engineering student, your animations and concise explanations enabled me to understand some parts and gain some new knowledge. From what I’ve seen in some old Newspaper article published in April 1984, it seems that VF Drives for high speed lifts were first invented in the 1980s. I’m assuming that the inverter mentioned in the article refers to a VVVF inverter. Here is an excerpt from the said article, “A major advance in energy saving, often by as much as 30 per cent, is now possible through the latest development in electric current control, the AC variable voltage, variable frequency (VVVF) system. Elevators have for a long time come in two basic types, featuring either AC geared or DC gearless drive controls; the former being normally applied for low speed (40 to 105 meters per minute) lifts and the latter for high speed (120 metres per minute or above) units. The conventional geared-type needs a gear to control the lift because of the difficulty in stably controlling motor rotation, especially at low speeds. Disadvantages include high vibration and noise levels. DC motors are easy to control at high speeds, but consume high levels of power. In October last year, Toshiba was the first company to announce the development of an AC gearless high-speed elevator. The equipment features the VVVF inverter, which simultaneously controls with great accuracy the voltage and frequency of the AC motor, thus enabling a 30 per cent lower power supply capacity, and saving an overall 10 per cent in power consumption. The company says it is possible for a 105 metres per minute elevator, with a capacity of 15 people, to consume only 17 to 18 kw hours per day of electricity, if equipped with VVVF control, against 34 to 35 kw hours per day for a conventional system. Mitsubishi Electrical and Hitachi also plan to introduce AC gearless VVVF units within this year. Mitsubishi has also already introduced the VVVF technology into low speed AC geared equipment.” I believe that for traction lifts, this article omitted mentioning about lifts using geared DC motors. I am also a bit confused as to what the difference is between Variable Voltage AC and VVVF lifts, given that VVAC lifts started appearing in low speed lifts from around the late 1970s, and these lifts are able to level much quicker than lifts using AC 2 speed motors . Is the main difference that VVAC only varies the voltage while VVVF can vary both the voltage and frequency? If yes, what difference does varying the frequency help to achieve and why would varying just the voltage not be enough? As for DC motors, it seems that in the 1980s, besides the usual AC to DC motor generator, lift manufacturers started using other technologies to get a DC power supply including but not limited to thyristors, pulse width modulator (PWM) AC to DC power converters, as well as Silicon Controller Rectifier Drives. I have no idea how any of these technologies work. If you would be so kind as to enlighten me (and others), about these things, that will be much appreciated.
Thanks for the comment, very interesting. I didn't know about the gearless AC high speed motors. I'm only really researching old elevators, new ones don't really interest me that much so it's difficult for me to do a video on it.
14:04 it's quite neat to see an old Veeder-Root gauge was used overseas all those years ago. I've lived in Connecticut all my life just a few towns over from Hartford
Thank you and glad you enjoyed it. Months of thinking 'shall I realise it, or shall I add more to it...!?'. 4 months later it's ready!! Although 28 minutes is a little too long in my opinion, was going to make it a part1/part2, but that'd need even more work and more time editing... so I got to a point ''I HAVE to upload it now''
Excellent video, thanks for creating and posting it. It’s all before my time but I love the old electromechanical stuff, brilliant to sit and watch it go thru it’s steps. Not like the black boxes of today’s world. All the best.
Worked on a lot of electromechanical logic, even on modern PLC systems there still will be some there, doing functions that the PLC is deemed too unreliable to do, like safety switches, and power sequencing.
Once again your research, detail and animations have created a stunning video that informs and entertains. I actually learn from your videos. I wish you could do a video to help me with my calculus.
Amazing how this old schindler logic works. All this, for only five landings,This overenginering things is so amazing. Moderns logics are more efficient but boring hahahaha. More videos like this
An excellent video very detailed. This elevator system is unique and very complex as to the 3 MG's sequence of operation. I've not seen a video till now with a DC traction machine that had more than one MG set. Even the previous maintenance engineer position I held, the elevators were DC traction just with an single MG and six landings. I can understand a little of the narration and the diagram how this works, sounds like an earlier version of the leveling field in the later Otis Gear-less high DC traction machines with the pie-plate floor selector. The MG cuts out as the cab reaches the floor landing, leveling field cuts in.
Thanks very much for the comment, yes very interesting lift! This concept was designed in the late 1940s from my understandings, goes a long way back...!
I remember the distinctive sound of what I always heard called a "dynamotor". A 3-phase motor driving a DC generator. Maybe that's a generic term, or a US term. The growl then whir is very distinctive.
at first sight: GF is propably a power supply for prime mover field, GZ field, brake (BM). Prime mover's (MH) field direction is selected by RU relays, and so decides the turning direction of the motor. There is also propably a relay "rbm" in series with MH field, it controls if the field currents flows, if one would start this circuit with no field current in MH then bad things would happen. GF is propably self excited generator, resistors are propably for regulating the output voltage. It bootstraps from the remnant magnetism. I have no idea what MK is. Maybe some relay to control if GF generates voltage? But all other relays are drawn with shorter zig-zag (like rbm). Author told that BM is brake electromagnet, so WB is surely resistor to pervent voltage spike on deenergising and maybe also due to it's existence brakes apply less harsh. GZ is generator for main generator (GE) field, it functions as an amplify stage (probably) and smooth-speed-envelope source. The J-K winding is energized directly from stable GF voltage, through resistors, like is said in the movie, swithing the relay's concats in this circuits changes the current in GZ J-K winding and so changes voltage generated in GZ (and finally selects at what speed the elevator moves). But there is also second GZ field winding: J1-K1 (if i properly see in this pixelated stop-motion schematic on the video). This winding has circuit separated from the outer world, so my only guess is that it does same thing as copper slugs on slow operating relays. I will explain: When relays decide to change elevator speed, they change current ion J-K winding (with the help of resistors). But J-K and J1-K1 are two windings on same core, so the GZ stator's core and field windings behave like a transformer. Change in J-K current induces current in J1-K1, the magnetic field is sum of those up so the voltage GZ produces will not change. Actually it will, the induced current in J1-K1 will decrease soon, as this is not superconductor, so the voltage GZ produces will slowly move towards new value. Actually there is WZ resistor and some concats, so propably they are for changing the acceleration speed of this voltage. The main generator field winding GE J-K is powered directly by GZ generator, so basicaly the voltage supplied to prime mover will follow voltage generated in GZ, and so the speed will. But, firstly, actuall speed is function of voltage apllied and load, so if there are lot of people in elevator, it will move upwards slower than if empty. There is also second fact that makes this worse, the generator's voltage will decrease if more current is drawn. This two things are compensated by this winding E-F betweend MH and GE rotors. This winding current is the same current that flows from generator and flows to motor, a more load in motor -> more current. This winding adds up to the GE excitation so it will produce even more voltage and compensate speed differences of empty/full elevator. There is also this GE J1-K1 winding, it has two functions. One is a (i don't know in english, in my country we call it "połączenie samobójcze") let's say, field-suicide-circuit. When elevator is not moving (and RE, RY relays deenergised) GE rotor is powering the J1-K1 winding, but this connection is a opposite of self-excitation generator, so if GE generates any voltage, it will kill it's excitation and remnant magnetism. This is important, otherwise there would be voltage on the prime mover all the time the GE spins. If elevator moves, RE and RY are energized and there we gave propably a second stage of the same thing that i said about GZ J1-K1: changes to the GE J-K current will be smoothed out. It looks like a simple design, these field enevlopes are not linear but like capacitor charging curve, but for some reason cascaded two times. There is still question "why GF generator, not trafo+rectifier?" I guess, due to the better voltage stability and/or amount of required power. Rectified and not good filtered AC voltage would propagate to the MH and GE excitation and cause speed wobble and eddy currents in field cores. Well, i wished to write two sentences and finally made a full essay, thanks for everyone who read all ;) BUT THIS IS ONLY MY FIRST-SIGHT INTERPRETATION, I see this circuit first time in my life, im basing only on this circuit i can observe by pausing this video. If anyone has suspections that i may be wrong, this is very possible and please let me know! PS: if this is a movie about such ward-leonard elevator, im not sure if those lessons "what electrons and alternating current is" are needed, uneducated people will not understand anyway, educated ones will get annoyed like "i im watching amazing movie about amazing lift, why the hell someone then starts babbling about shool electricity basics?".
Thanks very much for all that - reading it all now...! By the way, watched your 'Gdy dwie windy w grupie jeżdżą razem na wezwania' video the other night from end to end (using translate). Very interesting. Are you ever afraid someone might steal your camera when you're on a different floor?
''Well, i wished to write two sentences and finally made a full essay, thanks for everyone who read all ;)''. Haha, thats the story for every one of my videos - starts as something simple, and ends up taking months!! About the ''what electrons are'' yes I do see your point, which is why I put ''please bear with me this is quick''. Hopefully some people will benefit, and will help them understand the next part (possibly!).
@@mrmattandmrchay > (using translate) Well, someday i really have to sit, review my videos and add English subs to them. > Are you ever afraid someone might steal your camera when you're on a different floor? I was there with my friend, he kept eye on the camera. Usually im not leaving it in places where there someone might steal it. > Haha, thats the story for every one of my videos It's just life. > About the ''what electrons are'' Don't get me wrong, keep in mind i know about electrons since ground school, and sometimes behave like "what, how a person can live without knowing it, it's so fundamental as eating breakfast", i just sometimes forgive that on everyone is such a freak as me. But how about making separate educational videos and refer to them in other ones? Benefits: more total channel views, less work on elevator videos, more audience (like, someone searching for "how electrons flow" find your channel and starts to like elevators too). I'm pretty sure there are dozens of people who might passionate about elevators but they don't know about it until someone show it to them. I wasted 20 years of my life in unconsciousness about elevators. You are doing good job and never, for god's sake, never stop! Now my second sight on the schematic: Previously i skipped the WR resistor. I'm still not sure what is it's function, but it looks like that if GZ creates voltage, then this resistor is connected between two generator's rotors, so propably only creates heat. But if GZ is cut out with it's concats, the main GE generator winding J-K is supplied from GF's constant voltage through this WR resistor. I have no good idea about it. And the MK winding, isn't it door locking electromagnet? It is surrounded by symbols that are propably hoist cable, so surely its something mounted on the cabin. I wonder how effective (if any) is this shorted-winding method of gaining smooth acceleration. The Ward-Leonard elevator's made by Polish ZREMB (under asea-graham licence) used magnetic amplifier. There was similar winding in main generator, but current induced in went as negative input to the amplifier. With some more magic and pair of zener diodes it makes the elevator have almost constant acceleration value.
The first thing that caught my attention was that there is no contactor between the 355V generator and the lift motor, that means the whole show is controlled by varying the field windings of the 355V gen, the two smaller generators never actually power/run the lift, they just excite the fields of the 355V gen, hence they been way smaller. What Schindler have achieved is making a variable voltage DC source, including DC polarity, to run the main motor. Kind of brilliant if you ask me....
The United States started using PLCs in elevators in the 1980s as well as VFDs and we were early adopters of a lot of the technologies for elevators/lifts, especially Otis. There was a transition period in the 1980s to 1990s where it had PLCs but still had 3 DC generators.
It's amazing to think about just how much work that goes into designing stuff like this! After all it's not just a matter of controlling a motor to move a car and make it stop in the right places...But doing all of the above _safely!_ 💯 One thing that always worries me about modernisations to stuff like this is where corners might be being cut. You can see (And fix) omitted door closure contacts on a Schindler wheel, but can you see and fix a critical flaw in the software of a modern VFD that was bashed together on a Friday afternoon in an low-rent office on a completely different continent? 😳
You make the bast elevator content and the best visuals of most any genre of channel. The effort is amazing that you go to explaining with great animations what is going on. Thank you.
well i would say you need basically the same generator even for 20 floors since the only thing that changes are the stops, maybe the selector wheels gets bigger but the motors stay the same
Another awesome video again. That is a complicated system with those three motor generators. I heard some Dutch words spoken in the beginning. Was this installation somewhere in The Netherlands? Also noticed a few Dutch words on the equipment (omvormer). This video must have taken days/weeks to edit and make the pictorials in the editor. Great work. Happy 2024 in advance.
I'd expect the main motor speed control to function by controlling the generator field current, rather than it running at full output all the time and having some form of [very wasteful] control in the power circuit itself. That type of system is (or was) very common in industry for controlling large DC motors, though often with one motor running the various generators via common shaft setup. One of the smaller generators likely provides the control gear supply voltage & the other may? provide the field supply for the big one, controlled by either resistor banks or a valve (vacuum tube) amplifier. One of the versions of that control system is the Ward-Leonard set, there are also such as Amplidynes and other systems & brand names.
Some of the later AC-DC systems used generators as a means to generate a feedback voltage, that was used to modulate the excitation current in the generator.
Another excellent video. We called M-G's 'dynamotors'... probably a brand name... it's what you did when you wanted HV DC from AC or from lower DC... tube-type mobile radios would use either dynamotors or vibrator circuits with rectifiers to generate the 400vDC required for hi-power radio transmission in the vacuum tube (valve!) era. I guess you could use giant mercury rectifiers for the DC... those things are beautiful and scary at the same time.
The NYC subway system used mercury-arc rectifiers to replace rotating equipment at some locations, but they had problems with mercury-vapor leaks. (I do not know if they have been replaced by solid-state devices.)
Ah good Ole' Schindlers, I just love how almost... Overengineered (for a lack of a better word) their systems are.. I recently ran into a Schindler SmartMRL w/ the touch-sensitive panels, I've seen the guts of one of the landing call stations (after some careless employee pushed hard on the button) and the amount of stuff going on in there it's downright ghastly! On a side note, I thought it was a modernization install, since near that elevator there's a door that leads to an attic above the shaft, but I went there with a colleague (I was just an intern there!) and couldn't find any traces of an old installation... Perhaps it may very well have been a torpedo counterweight hoist? I did notice another door on the ground floor with a crossed out "MACHINERIE ASCENSEUR - DANGER" sign on it.. Said door was boarded up shut, so we couldn't investigate further.. The building came up in the mid-1800s, so I wonder how many installs and modernizations took place... ETA: 6:35 vaccum tubes and relay logic?? I love it, I never thought I'd see that but here we are 😂
I now wonder how the elevator at the Center in the Square Garage in Roanoke, Virginia, United States works. It is a 1981 Dover with variable frequency drives on relays
Interesting, by adjusting the field strength they would get energy recovery (large generator will return some power back to the mains when slowing the lift).
translation ''Great video. Understanding how these wonderful machines work left me fascinated. Happy New Year.'' Thank you very much Sergio, and best wishes to you for 2024! :)
@mrmattandmrchay The simple way i think how to explain it is the smaller permanent magnets DC generators supply the field excitation for the main generator. Up to 130 VDC varied by resistors for start slow and stop. second field excitation winding with 90 VDC for fast speed.
Smaller ones are separately excited field, and resistors are used to control field current in each, allowing for the field current to be weakened for the main motor, for high speed operation, and then increased for slow, and then via a time delay relay to an even higher creep speed close to the floor level. you can hear the 3 speeds and the slow ramp as the DC generators slowly build up field via the resistors on stopping, and on start RC timers do the rest.
I was always told that DC lift motors were uses since they had better torque at low speeds and easier to control with the available technology. I've only been involved with industrial lift of 1960's vintage made by Otis and then only for rescuing trapped users.
I predict that I will be able to understand that drawing in about 2 years time. I've learnt a lot over the past few years, however, I've only just started learning about 3 phase AC induction motors, and I'm not sure how the magnetic fields interact in these rather standard motors, let alone in a DC generator! The system in your video is fascinating, but a little too complex for me!
Hi Michal, I didn't feel that I understood it enough to fully explain it, hence the conclusion I gave at the end. I did try to find out all I could, and I knew the community would fill in the gaps. Every day is a school day!
It seems like diode banks would make more sense than the motor generator setup. Was it more cost effective or more reliable to have this setup? I realize this gives three voltages. But ac voltage change is easy with a transformer.
In minecraft(create mod)i build a lift with seqensed gearshifts and what i think at you can say is the lift motor is running "on time"/its running on a time to exemple if the lift gets a call one floor above its need a speific time to reach the call.Idk if this would help but i just want to say about it.
Yep, I actually went to this place about 3 months ago (same place as LiftDragon), but unfortunately it was out of order, when I went there and it's now LONG TERM out of order (possibly waiting to be modernised). LiftDragon went there about 3 months before I did when it was working. So I did plan to upload a video for it, but probably won't now, and LiftDragon's covered it anyway.
Great video! My question is, how does the lift logic determine whether two calls are one floor apart or many floors apart? How does it know whether to go at high or low speed? I don't understand how this would be done before microprocessors since you would need some kind of subtraction logic.
You don't need subtraction. I don't know how this system actually works but I can make a guess. The selector pushes one way on a switch bank for all the floors below the current position and pushes the other way for floors that are lower. Signals can run in a line through the switches. The call logic could energize a line on the corresponding selector switch where it would energize a "next floor" signal. If the call is further away the next floor switch would reroute the "next floor" signal to a "far floor" bus. Then the currently selected floor switch would route the "next floor" and "far floor" signals into the control logic.
That is a normative statement based off your own value judgement. If you were to ask Japanese lift enthusiasts whether they think Schindler is the “best modern day lift company”, they’d think you’re joking.
@@elevatorfilmersg In the UK, Schindler Beats nearly all of the Big Manufacturers. Otis Very recently have gone Ultra Cheap, ThyssenKrupp have been Very Cheap since 2015, Kone's Lifts since 2016 have been going Characterless, Then there's all the 3rd Party Manufacturers (Excluding Orona, Kleemann, Dewhurst and Schaefer) that have been installing Very Cheap Lifts of Very Poor Quality, All assembled by Loads of different Manufacturers such as Raloe, Ziehl Abegg, MP, VEGA and many More. The likes of defunct Manufacturers such as Express and Bennie were a backbone of Lifts in the UK. The only Top Notch Lift Manufacturers in the UK now are Schindler, Dewhurst, Digital Advanced Controls, Orona, Mitsubishi, Fujitec and a few more. Unfortunately the UK doesn't get many Mitsubishi or Fujitec Lifts.
these AC motors are alos induction motors which are asynchronous motors, making position control even more sophisticated. They rely on slip to produce torque because of their inductive nature, where a stator field must be cutting (rotating) the rotor cage to produce the cage current for interacting with the stator field, i.e. the stator field rotation speed MUST be faster than the rotor speed for torque production.
What I wounder is why they didn't use a multi current motor in the lift motor. Those was often used in trains and could be trottled in diffrents step. Typicallt with a multiplicable resistor away. Say 3x3 resistors of a total of 9 speeds. There is actually a dussin ot so ways to make AC controlable. The reformer system was also quite common. Typicallt most system work by changing the current to the magnitizarion this way the output speed or voltage can be change wirh a very small loss of power... Well.. small for the time
16:40 i think that is if only partially true since it was much easier to control DC back then, all the new stuff with vfd and such are relativly "new" (and reliable in da to day appliances) 18:46 also not really true i don´t think that a commercial building that would need such a lift don´t has 3 phase to it, heck over here in germany it is normal that every household has 3 phase service to it
There is a little extra logic added to the floor with 2 doors, to allow the second door to open only on that floor. You just add the second door, the second door motor, and the second retiring cam, which is only enabled with either being on that floor, or by having extra logic, that will only enable it if the rear door button is pressed inside the car, or the call button. depends if you want to allow through operation or have it specifically need to be on request, probably by pressing 2 inside the car, which will flip a relay set to open that door, or entering from 2 pressing 2R, which will do the same with similar relay logic. most common though is both doors open on that floor.
Adding on to @seanBZA comment, if the rear door was at a different level than the front door, then it'll be added as a new floor to the selector. Then the logic of which door opens, I'm guessing can be activated by an extra switch on the wheel - when both front and back should open, or just front or just back. - depending on the position of the lift car, and the activation of this switch.
Yeah - now skilled labor is almost undesired even at cheap prices (if it works perfectly - they won't have a call for return) Actually I'll expand a bit more on that. At the "boomer" time all these new things were coming out - for example the quadrature (whatever) VCR from 1968. It had to be manually adjusted at startup each time. Now it's done automatically. We did out job too well! Now the only way for repeat customers is updates (which Now can be deployed as a firmware update) and something that fails
I would say the reason they installed the DC motors, instead of a much cheaper 2 speed AC motor, was to have a much larger car capacity, and also to not have snatch on the car, probably because they expected to transport heavy delicate loads. Or the controller was mostly built for another order, that got cancelled, and this order was rush, so they used what was in stock controller wise, with only needing to do rope length and travelling cable runs, the rest already having passed factory test. Frame with 2 bays is way too big for the number of floor relays, likely this was originally for a 20 plus floor building, just got cut down for the 5 landing use.
The Ward Leonard system is complex, but has the advantage of start torque being very controlled, so giving a nearly imperceptible start and stop, which in a big lift can be a good feature, and the high speed in between floors is ramped up and down smoothly. The large motor generator has both the voltage and the current varied by the smaller ones, the lower voltage excitation is applied to the field to slowly bring up the power, and then switches to a higher voltage at full run speed, and also the main hoist motor field is varied as well, changing the amount of power it can deliver to ramp smoothly up and down.
Been a long time since I looked at them, but the 90VDC generator provides the shunt field for both the 130VDC unit and the 130VDC in turn provides the large generator and the hoist motor field, with the resistors being there to limit current flow, and thus field strength, and thus the power output of the motor, and thus how fast it will slew up or down in speed. Fixed resistors are there to ensure that the generators will not provide any output voltage with no field current, because of remnant magnetism, and thus keep them from operating any relays or drive when they are being shut off. There will be a transformer providing 48VAC, powering the button logic and lamps, that also operates the motor shut down logic after 5 minutes of inactivity, set using a sensitive coil relay, and a very large value electrolytic capacitor, that takes 3 minutes or so to discharge the capacitor below the coil hold voltage, and this operates the main motor contactor. Press any button and the motor generators will all spool up, and after the 90VDC has reached operate voltage, closing an enable relay, it will run the lift. When all calls are satisfied, the relay contacts that keeps the big capacitor, charged via a big fixed resistor to keep contact current low, will all be open, and the capacitor will slowly discharge. Time adjustment is crude, you add more capacitors in parallel, till you get the right time.
Great explanation, are you or have you been a Schindler engineer?
AC to DC Rotary Converters are used due in Power Cuts - Emergency The Lift can still go To the Closest floor Due the AC to DC Rotory Converter still has torque & Fly Wheel rotational energy.
In a Emergency
if someone Straw/ Wood ice cram stick Block Certain Relays ( Plus a Few 9V 'Dry' Batteries) You can Trigger the Gravity break to Release and have a one way slow going down to Ground floor
@@hi-tech-guy-1823 You release the brakes manually, and then wind the car up to the next floor, as the counterweight is calculated to be just slightly heavier than a full car. Needs 2 people anyway, one to turn the handwheel on the motor, and the other with a break release lever, turning the brake to the off position. Brake releaser keeps an eye on the selector, and stops it at the next floor up, and then you go open the door and release the people inside.
Lose mains power and the control relays all immediately, within 2 cycles, drop all out, as they are fed from either a 24 or 48VDC or AC supply, from a transformer. Car will coast for around a tenth of a second, before the main brake fully engages, and abruptly stops it, normally with a rather massive jolt, even if the brake is engaging slowly.
Only on modern inverter controlled lifts can you have a large enough DC bus capacitance that will power the controller, so that it can drive the inverter into an emergency brake mode, recovering energy into the main capacitor bank, and thus slow the car down with around 5 seconds of power, perhaps enough to be close to a floor, but with a lot less stress on the brakes and cabling. Then will hold it stopped till the main DC bus undervolts, and the doors fail safe to open position under spring tension, and the controller does a final write to non volatile memory about the mains fail, and position of car for logging.
Main micro might be able to run for 20 seconds or more, so HMI inside the car will be active with emergency warning, and the emergency lighting, if it has been properly maintained, will be on allowing people inside to be less that terrified in the dark.
Incidentally, the most common brake models I have seen either, like Schindler does, uses a 3 phase motor, running locked rotor, turning a small gear train that drives the brake pads out of lock against spring tension. Or they are the Otis/Express/Fiam ones, with a massive solenoid running off 130VDC at 3A, pulling the brake pads off the drum. Coupled as well to the retiring cam, similar drive arrangement, so you need a rather hefty battery bank to actuate it, a pack of 15 PP3 cells in series is not even going to make it move a little.
Incidentally was working on an inverter drive, 5 full height cabinets, where 2 of them are reserved for main DC bus capacitors, around 100kJ of stored energy in them, and a cabinet on top, with 50A silicone cables, and some serious fan cooling, that connect the brake dump resistors in case the bank rises too high in voltage. Has a set of power on resistors as well, to keep the surge down on charging to something the 800A mains supply will be happy with. With 6 little 10kW motors, and a main 22kW motor, it is using some rather serious inverters, and it came with a quick install guide that is close to 1000 pages. Plus 3 engineers from all over the planet to oversee it. Google translate was useful, though they did learn a good few swear words in the time as well, and also got to see the wildlife as well, which they absolutely loved.
Thank you very much for your definition. Everyday is a school day! :)
@@hi-tech-guy-1823 towering inferno style?
That whole apparatus speaks to a time when copper and skilled labour were cheap.
Also these machines were a large fixed cost, so 2 to ~3 floor commercial, and 2 to ~5 floor residential low-rise elevators were more rare. They didn't have the disability access laws we have today.
If anyone needs a person to sit and watch a system like this all day I’m available.
Fascinating stuff!
In Wellington New Zealand we had two pairs of these operating at the Bay Plaza Hotel and Central Park flats, they were only modernized in the 90’s Beautiful stuff to work on, calls were latched by magnetic car buttons that only released when the lift changed direction after serving all floors. The central telephone exchange had a pair of gearless very similar but had two generators on the one motor to power the machine, acceleration was done via a motorised resistor feeding a saturable reactor
I can see a lot of parallels with original electro-mechanical pinball machines, relay logic is really fascinating!
Totally agree haha! Much better than watching a circuit board and LCD screen!
I was gonna say that too.. HAHAHAH
It amazes me how much time, effort, knowledge and money must have gone into constructing this amazing machinery! I thought that the Schindler dynatron already were machinery beasts but the lift in this video really blew my mind! Thank you for the time and effort you put into those videos! It is exactly what these machines have deserved!
It's a very elaborate design, but very interesting too! Thanks for the comment and compliment :)
Thank you very much for this truly outstanding video with the very detailed animations and explanations! Dynator is now too an almost extinct system and I'm glad that you presented it to the world!
As of the workings - I would have to study the schematics fror longer but what I would say as of now is that Dynator looks a lot like the predecessor of Transitronic, the later Schindler high-speed DC drive system. I have a theory: Transitronic too has the main motor's and generator's rotor windings directly coupled together with nothing in between (except the WG resistor here). The main motor and main generator of this system use a separate supply for the field winding, just as with Transitronic. Now here's the catch: How do you get the separate voltage? On newer Transitronic it was possible to generate this voltage directly from AC through rectifying because in this later are of time, strong enough semicondictuors were available. But back in the 50s and early 60s that was not yet the case, so an extra smaller generator was used - one that didn't need separate voltage for itself to work. That also is, how the actual Ward-Leonhard machine works: It is two DC generator on the same shaft together with one AC motor, the smaller generator generating the field voltage for the big one. Then resistors can be used in that smaller circuit to vary the field voltage of the big generator, thus varying the actual output voltage of the big generator with relatively small losses.
As a very new 1st year apprentice for a small lift company in the AUS, I love seeing old gems like this. I just wish more of these were kept, but as years progress it seems that we’re heading towards overly simple and bland affordability. Going off by some lifts I used to know, most of them get replaced after 15 years of use, yet these old lifts can last many years! With the proper maintenance/care.
I always knew that a lift would be a complex system.. but I had no idea just how complicated it would be. Awesome video.
Anything not absolutely trivial done in pure electro-mechanical logic will get pretty complicated really quick compared to TTL/CMOS logic on a PCB, which itself looks ridiculously complicated compared to more human-friendly C/C++ or higher-level language code for a micro-controller.
these are super high quality love these! amazing work
Must have been a very expensive installation in its day.
Indeed! Makes you think why they didn't just use an AC motor for a building with 5 landings, but this video wouldn't have been as interesting if it had been!
Another amazingly detailed video, I will never tire of seeing those mechanical floor selector systems working.
I love seeing a cabinet full of pulleys and motors.
Wow that amazing love the work that went into mechanical switching before digital programming and verbal frequency drives
Variable frequency drives
I worked as an elevator fitter and replaced many of these old systems with new microprocessor-controlled systems. Mostly with NewLift or Kollmorgen controllers in conjunction with Ziehl Abegg machines. In my opinion, Westinghouse had the most complex and largest control systems, especially when it came to group control systems. Who can still remember the tuning toothpicks in the control relays?
Ah, do you mean the DMR systems like this one...? th-cam.com/video/FVgDDEf57s0/w-d-xo.htmlsi=QbrIoGjavDAT54EH&t=440 I filmed one a long time ago (th-cam.com/video/hz7NvgZaoDM/w-d-xo.htmlsi=wT1iEnF0vb299nF5&t=141), would do anything to see another one working!
I had a basic understanding of elevators but nothing like this, I have entered a completely new world of “elevator technology”. From a novice standpoint I like the older mechanical/analog technology compared to the newer stuff. It’s like comparing a Steam locomotive to a Electric locomotive. Looks like I found a new channel to watch. Thank you for the great video
I find elevator logic fascinating! Thank you very much for watching and the compliment Kevin.
There is a lot of bonus features here that would not be standard at the time.
Never seen Schindler's Lift before... 'bout time I did ;)
I just _knew_ it couldn't only me me trying as hard as possible to resist(or) that joke! 🙃
Love the old machines with Ward-Leonard sets. Of course it's complicated, bulky and inefficient by today's standards, but it's just too cool to watch. As far as I know, they're pretty reliable too. There are still some cable cars and ski lifts around with the same technology, among them is the peak aerial tramway at Kitzsteinhorn with the pretty tall tower. According to the lift operator, the original drive system has never been changed since 1966, when it was built, and it still runs flawlessly till this day.
That’s an interesting way to accomplish a ward-Leonard drive. Wish this elevator was still operating.
As an engineer and elevator inspector, I loved these old machines with their motor-generators and "pinball" logic boards, alas most of them have been replaced with the very mundane roped-hydro type machines. Schindler was a good company to work with, nearly as good as Otis and Westinghouse.
When this system was installed in the 1960's it is obvious that Schindler were still using 1930's technology.
By the end of the 50's, Express had developed a floor selector fitted into the control panel, and it was indexed up and down by solenoids trigged from the lift shaft. the manufacturing costs were negligible compared to what we see here, and the reliability breathtaking. Having worked on many Ward-Leonard systems, this appears to be lunacy in ot's day. Love it, though!
Till that shaft had excess play, and you could have the car miss a tappet slot, and bypass a floor. I was almost tempted to go into that shaft with a load of steel plates, and jack the shaft back to true, but instead we upgraded the controller to an Otis unit. Well 3, first one got blown by the trailing cable hooking up, and applying 230VAC to the 24VDC circuits, and so did the second one, for the same reason. 3 controllers, and 100m of heavy flat trailing cable later, plus some rather brutal work with a grinder, to remove the sharp edges of the car, and that last one worked perfectly.
Plus Otis had underquoted badly, but held to the quote, though the price we paid just covered the cost of only the controller, not of any work, or cables, or tapes, or any of the other stuff needed. But they had held that contract for 30 years, so ate the cost. I do have a piece of cardboard box, crudely ripped off, and with a crude wiring alteration drawn on it, that is in the master drawing file, complete with a laminated cover, signed off by the local PR.Eng from Otis. I added one extra jumper, and moved one wire over, to fix an issue where the current in the retiring can, and the brake coil, was being passed through a single contact in a 3 phase breaker, the one used to break the safety circuit, and the third unused. 3A per coil ,and it would trip if you went full stroke, with no stops, twice in short order, as the 2 currents were 6A, and the breaker is 5A. Split so 2 contacts now had 3A each, and no tripping issue, and breaker was correct for the use.
Yes, and it's very interesting to see what each manufacturer comes up with regarding designs! Schindler is certainly very elaborate!
This system was also manufactured in Hungary under license by Ganz-MÁVAG. There are not many left, they have been rebuilt. Even with the motor, only the fast side works with a frequency converter.
Agreed - would be very lucky to find one of these still working.
They should make a movie about this: Schindler's Lift.
I only clicked the video to come find this comment 😅
Different Schindler.
@@b43xoit NO WAI! /s
Ahh...I was filming a Schindler earlier and cracked the same joke, despite my dialogue being in German¹... 🙃
(¹ - I'm actually English and was filming one of my local lifts...But not having been abroad since before the pandemic and _really_ missing those lands I love 🇩🇪🇪🇸🇨🇵, I'm trying to take a break from íngles when I can! 😇)
Hi mrmatt, your content never disappoints!
Although I’m still unable to understand everything given that I’m no engineering student, your animations and concise explanations enabled me to understand some parts and gain some new knowledge.
From what I’ve seen in some old Newspaper article published in April 1984, it seems that VF Drives for high speed lifts were first invented in the 1980s. I’m assuming that the inverter mentioned in the article refers to a VVVF inverter. Here is an excerpt from the said article,
“A major advance in energy saving, often by as much as 30 per cent, is now possible through the latest development in electric current control, the AC variable voltage, variable frequency (VVVF) system.
Elevators have for a long time come in two basic types, featuring either AC geared or DC gearless drive controls; the former being normally applied for low speed (40 to 105 meters per minute) lifts and the latter for high speed (120 metres per minute or above) units.
The conventional geared-type needs a gear to control the lift because of the difficulty in stably controlling motor rotation, especially at low speeds. Disadvantages include high vibration and noise levels. DC motors are easy to control at high speeds, but consume
high levels of power.
In October last year, Toshiba was the first company to announce the development of an AC gearless high-speed elevator. The equipment features the VVVF inverter, which simultaneously controls with great accuracy the voltage and frequency of the AC motor, thus enabling a 30 per cent lower power supply capacity, and saving an overall 10 per cent in power consumption.
The company says it is possible for a 105 metres per minute elevator, with a capacity of 15 people, to consume only 17 to 18 kw hours per day of electricity, if equipped with VVVF control, against 34 to 35 kw hours per day for a conventional system.
Mitsubishi Electrical and Hitachi also plan to introduce AC gearless VVVF units within this year. Mitsubishi has also already introduced the VVVF technology into low speed AC geared equipment.”
I believe that for traction lifts, this article omitted mentioning about lifts using geared DC motors.
I am also a bit confused as to what the difference is between Variable Voltage AC and VVVF lifts, given that VVAC lifts started appearing in low speed lifts from around the late 1970s, and these lifts are able to level much quicker than lifts using AC 2 speed motors . Is the main difference that VVAC only varies the voltage while VVVF can vary both the voltage and frequency? If yes, what difference does varying the frequency help to achieve and why would varying just the voltage not be enough?
As for DC motors, it seems that in the 1980s, besides the usual AC to DC motor generator, lift manufacturers started using other technologies to get a DC power supply including but not limited to thyristors, pulse width modulator (PWM) AC to DC power converters, as well as Silicon Controller Rectifier Drives. I have no idea how any of these technologies work.
If you would be so kind as to enlighten me (and others), about these things, that will be much appreciated.
Thanks for the comment, very interesting. I didn't know about the gearless AC high speed motors. I'm only really researching old elevators, new ones don't really interest me that much so it's difficult for me to do a video on it.
Outstanding work, should be used in the education of electrical engineers.
Cool. Thanks for sharing.
14:04 it's quite neat to see an old Veeder-Root gauge was used overseas all those years ago. I've lived in Connecticut all my life just a few towns over from Hartford
What a brilliant video. Thank you very much. This has clearly taken a lot of effort to make.
Thank you and glad you enjoyed it. Months of thinking 'shall I realise it, or shall I add more to it...!?'. 4 months later it's ready!! Although 28 minutes is a little too long in my opinion, was going to make it a part1/part2, but that'd need even more work and more time editing... so I got to a point ''I HAVE to upload it now''
this is an excellent video. Keep up the amazing work.
Thank you very much Andrew! :)
Excellent video, thanks for creating and posting it. It’s all before my time but I love the old electromechanical stuff, brilliant to sit and watch it go thru it’s steps. Not like the black boxes of today’s world. All the best.
Thanks very much techone!
It’s a great day when there’s a new mrmattandmrchay video. You have kindled a love of old electromechanical logic I never knew I had.
Worked on a lot of electromechanical logic, even on modern PLC systems there still will be some there, doing functions that the PLC is deemed too unreliable to do, like safety switches, and power sequencing.
Thanks very much for the compliment! :)
Once again your research, detail and animations have created a stunning video that informs and entertains. I actually learn from your videos. I wish you could do a video to help me with my calculus.
I want hillton park part 5 i am dying to see hillton park part 5 i will give you as long as you need to make hillton park part 5 and i love this video
I know I keep asking you this, but what exactly was it that I said in part 4? I can't remember what part 5 was about!? Thanks.
@@mrmattandmrchay part 5 is for a direction switch on a larger Goods lift
Awesome and super detailed video!! This is awesome work!!
Thank you crocoland!
Amazing how this old schindler logic works. All this, for only five landings,This overenginering things is so amazing. Moderns logics are more efficient but boring hahahaha. More videos like this
Looks like the selector apparatus in a pinball machine. Cool!
An excellent video very detailed. This elevator system is unique and very complex as to the 3 MG's sequence of operation. I've not seen a video till now with a DC traction machine that had more than one MG set. Even the previous maintenance engineer position I held, the elevators were DC traction just with an single MG and six landings. I can understand a little of the narration and the diagram how this works, sounds like an earlier version of the leveling field in the later Otis Gear-less high DC traction machines with the pie-plate floor selector. The MG cuts out as the cab reaches the floor landing, leveling field cuts in.
Thanks very much for the comment, yes very interesting lift! This concept was designed in the late 1940s from my understandings, goes a long way back...!
I remember the distinctive sound of what I always heard called a "dynamotor". A 3-phase motor driving a DC generator. Maybe that's a generic term, or a US term. The growl then whir is very distinctive.
at first sight:
GF is propably a power supply for prime mover field, GZ field, brake (BM).
Prime mover's (MH) field direction is selected by RU relays, and so decides the turning direction of the motor.
There is also propably a relay "rbm" in series with MH field, it controls if the field currents flows, if one would start this circuit with no field current in MH then bad things would happen.
GF is propably self excited generator, resistors are propably for regulating the output voltage. It bootstraps from the remnant magnetism.
I have no idea what MK is. Maybe some relay to control if GF generates voltage? But all other relays are drawn with shorter zig-zag (like rbm).
Author told that BM is brake electromagnet, so WB is surely resistor to pervent voltage spike on deenergising and maybe also due to it's existence brakes apply less harsh.
GZ is generator for main generator (GE) field, it functions as an amplify stage (probably) and smooth-speed-envelope source.
The J-K winding is energized directly from stable GF voltage, through resistors, like is said in the movie, swithing the relay's concats in this circuits changes the current in GZ J-K winding and so changes voltage generated in GZ (and finally selects at what speed the elevator moves).
But there is also second GZ field winding: J1-K1 (if i properly see in this pixelated stop-motion schematic on the video).
This winding has circuit separated from the outer world, so my only guess is that it does same thing as copper slugs on slow operating relays. I will explain:
When relays decide to change elevator speed, they change current ion J-K winding (with the help of resistors).
But J-K and J1-K1 are two windings on same core, so the GZ stator's core and field windings behave like a transformer.
Change in J-K current induces current in J1-K1, the magnetic field is sum of those up so the voltage GZ produces will not change.
Actually it will, the induced current in J1-K1 will decrease soon, as this is not superconductor, so the voltage GZ produces will slowly move towards new value.
Actually there is WZ resistor and some concats, so propably they are for changing the acceleration speed of this voltage.
The main generator field winding GE J-K is powered directly by GZ generator, so basicaly the voltage supplied to prime mover will follow voltage generated in GZ, and so the speed will.
But, firstly, actuall speed is function of voltage apllied and load, so if there are lot of people in elevator, it will move upwards slower than if empty.
There is also second fact that makes this worse, the generator's voltage will decrease if more current is drawn. This two things are compensated by this winding E-F betweend MH and GE rotors. This winding current is the same current that flows from generator and flows to motor, a more load in motor -> more current. This winding adds up to the GE excitation so it will produce even more voltage and compensate speed differences of empty/full elevator.
There is also this GE J1-K1 winding, it has two functions. One is a (i don't know in english, in my country we call it "połączenie samobójcze") let's say, field-suicide-circuit. When elevator is not moving (and RE, RY relays deenergised) GE rotor is powering the J1-K1 winding, but this connection is a opposite of self-excitation generator, so if GE generates any voltage, it will kill it's excitation and remnant magnetism. This is important, otherwise there would be voltage on the prime mover all the time the GE spins.
If elevator moves, RE and RY are energized and there we gave propably a second stage of the same thing that i said about GZ J1-K1: changes to the GE J-K current will be smoothed out.
It looks like a simple design, these field enevlopes are not linear but like capacitor charging curve, but for some reason cascaded two times.
There is still question "why GF generator, not trafo+rectifier?"
I guess, due to the better voltage stability and/or amount of required power. Rectified and not good filtered AC voltage would propagate to the MH and GE excitation and cause speed wobble and eddy currents in field cores.
Well, i wished to write two sentences and finally made a full essay, thanks for everyone who read all ;)
BUT THIS IS ONLY MY FIRST-SIGHT INTERPRETATION, I see this circuit first time in my life, im basing only on this circuit i can observe by pausing this video. If anyone has suspections that i may be wrong, this is very possible and please let me know!
PS: if this is a movie about such ward-leonard elevator, im not sure if those lessons "what electrons and alternating current is" are needed, uneducated people will not understand anyway, educated ones will get annoyed like "i im watching amazing movie about amazing lift, why the hell someone then starts babbling about shool electricity basics?".
Thanks very much for all that - reading it all now...! By the way, watched your 'Gdy dwie windy w grupie jeżdżą razem na wezwania' video the other night from end to end (using translate). Very interesting. Are you ever afraid someone might steal your camera when you're on a different floor?
''Well, i wished to write two sentences and finally made a full essay, thanks for everyone who read all ;)''. Haha, thats the story for every one of my videos - starts as something simple, and ends up taking months!! About the ''what electrons are'' yes I do see your point, which is why I put ''please bear with me this is quick''. Hopefully some people will benefit, and will help them understand the next part (possibly!).
@@mrmattandmrchay
> (using translate)
Well, someday i really have to sit, review my videos and add English subs to them.
> Are you ever afraid someone might steal your camera when you're on a different floor?
I was there with my friend, he kept eye on the camera. Usually im not leaving it in places where there someone might steal it.
> Haha, thats the story for every one of my videos
It's just life.
> About the ''what electrons are''
Don't get me wrong, keep in mind i know about electrons since ground school, and sometimes behave like "what, how a person can live without knowing it, it's so fundamental as eating breakfast", i just sometimes forgive that on everyone is such a freak as me. But how about making separate educational videos and refer to them in other ones? Benefits: more total channel views, less work on elevator videos, more audience (like, someone searching for "how electrons flow" find your channel and starts to like elevators too). I'm pretty sure there are dozens of people who might passionate about elevators but they don't know about it until someone show it to them. I wasted 20 years of my life in unconsciousness about elevators.
You are doing good job and never, for god's sake, never stop!
Now my second sight on the schematic:
Previously i skipped the WR resistor. I'm still not sure what is it's function, but it looks like that if GZ creates voltage, then this resistor is connected between two generator's rotors, so propably only creates heat. But if GZ is cut out with it's concats, the main GE generator winding J-K is supplied from GF's constant voltage through this WR resistor. I have no good idea about it.
And the MK winding, isn't it door locking electromagnet? It is surrounded by symbols that are propably hoist cable, so surely its something mounted on the cabin.
I wonder how effective (if any) is this shorted-winding method of gaining smooth acceleration.
The Ward-Leonard elevator's made by Polish ZREMB (under asea-graham licence) used magnetic amplifier. There was similar winding in main generator, but current induced in went as negative input to the amplifier. With some more magic and pair of zener diodes it makes the elevator have almost constant acceleration value.
The first thing that caught my attention was that there is no contactor between the 355V generator and the lift motor, that means the whole show is controlled by varying the field windings of the 355V gen, the two smaller generators never actually power/run the lift, they just excite the fields of the 355V gen, hence they been way smaller. What Schindler have achieved is making a variable voltage DC source, including DC polarity, to run the main motor.
Kind of brilliant if you ask me....
I think your animations are amazing and really bring your videos to life. Thank you for the effort you put into these.
The United States started using PLCs in elevators in the 1980s as well as VFDs and we were early adopters of a lot of the technologies for elevators/lifts, especially Otis. There was a transition period in the 1980s to 1990s where it had PLCs but still had 3 DC generators.
Another excellent mrmattandmrchay video! Thank you so much! Very informative!
Thank you very much Brunoais! Matt
Love this channel man
It's amazing to think about just how much work that goes into designing stuff like this! After all it's not just a matter of controlling a motor to move a car and make it stop in the right places...But doing all of the above _safely!_ 💯
One thing that always worries me about modernisations to stuff like this is where corners might be being cut. You can see (And fix) omitted door closure contacts on a Schindler wheel, but can you see and fix a critical flaw in the software of a modern VFD that was bashed together on a Friday afternoon in an low-rent office on a completely different continent? 😳
You make the bast elevator content and the best visuals of most any genre of channel. The effort is amazing that you go to explaining with great animations what is going on. Thank you.
A massive compliment, thank you very much :)
well i would say you need basically the same generator even for 20 floors since the only thing that changes are the stops, maybe the selector wheels gets bigger but the motors stay the same
Another awesome video again. That is a complicated system with those three motor generators. I heard some Dutch words spoken in the beginning. Was this installation somewhere in The Netherlands? Also noticed a few Dutch words on the equipment (omvormer). This video must have taken days/weeks to edit and make the pictorials in the editor. Great work. Happy 2024 in advance.
Schindlers Lift
I'd expect the main motor speed control to function by controlling the generator field current, rather than it running at full output all the time and having some form of [very wasteful] control in the power circuit itself.
That type of system is (or was) very common in industry for controlling large DC motors, though often with one motor running the various generators via common shaft setup.
One of the smaller generators likely provides the control gear supply voltage & the other may? provide the field supply for the big one, controlled by either resistor banks or a valve (vacuum tube) amplifier.
One of the versions of that control system is the Ward-Leonard set, there are also such as Amplidynes and other systems & brand names.
Some of the later AC-DC systems used generators as a means to generate a feedback voltage, that was used to modulate the excitation current in the generator.
In my world the DC generator is called a Ward Leonard generating set
Another excellent video. We called M-G's 'dynamotors'... probably a brand name... it's what you did when you wanted HV DC from AC or from lower DC... tube-type mobile radios would use either dynamotors or vibrator circuits with rectifiers to generate the 400vDC required for hi-power radio transmission in the vacuum tube (valve!) era. I guess you could use giant mercury rectifiers for the DC... those things are beautiful and scary at the same time.
The NYC subway system used mercury-arc rectifiers to replace rotating equipment at some locations, but they had problems with mercury-vapor leaks. (I do not know if they have been replaced by solid-state devices.)
Used to have a car radio with a vibrator.
Did you make a list before?
Freaking insane.
Ah good Ole' Schindlers, I just love how almost... Overengineered (for a lack of a better word) their systems are.. I recently ran into a Schindler SmartMRL w/ the touch-sensitive panels, I've seen the guts of one of the landing call stations (after some careless employee pushed hard on the button) and the amount of stuff going on in there it's downright ghastly!
On a side note, I thought it was a modernization install, since near that elevator there's a door that leads to an attic above the shaft, but I went there with a colleague (I was just an intern there!) and couldn't find any traces of an old installation... Perhaps it may very well have been a torpedo counterweight hoist? I did notice another door on the ground floor with a crossed out "MACHINERIE ASCENSEUR - DANGER" sign on it.. Said door was boarded up shut, so we couldn't investigate further.. The building came up in the mid-1800s, so I wonder how many installs and modernizations took place...
ETA: 6:35 vaccum tubes and relay logic?? I love it, I never thought I'd see that but here we are 😂
What makes them choose DC generator instead of transformer and rectifier ? Seems a lot easier to do than a motor-generator
Rectifiers back when this was installed were not capable of controlling the high ampage that was required to turn the motors.
I now wonder how the elevator at the Center in the Square Garage in Roanoke, Virginia, United States works. It is a 1981 Dover with variable frequency drives on relays
Interesting, by adjusting the field strength they would get energy recovery (large generator will return some power back to the mains when slowing the lift).
Grande vídeo. Entender como funcionavam essas maravilhosas máquinas me deixam fascinado. Feliz Ano Novo.
translation ''Great video. Understanding how these wonderful machines work left me fascinated. Happy New Year.'' Thank you very much Sergio, and best wishes to you for 2024! :)
@mrmattandmrchay The simple way i think how to explain it is the smaller permanent magnets DC generators supply the field excitation for the main generator. Up to 130 VDC varied by resistors for start slow and stop. second field excitation winding with 90 VDC for fast speed.
Smaller ones are separately excited field, and resistors are used to control field current in each, allowing for the field current to be weakened for the main motor, for high speed operation, and then increased for slow, and then via a time delay relay to an even higher creep speed close to the floor level. you can hear the 3 speeds and the slow ramp as the DC generators slowly build up field via the resistors on stopping, and on start RC timers do the rest.
I was always told that DC lift motors were uses since they had better torque at low speeds and easier to control with the available technology. I've only been involved with industrial lift of 1960's vintage made by Otis and then only for rescuing trapped users.
Didn't know this one is in the Netherlands, absolutely lovely but sad it's not running anymore
Good video keep it up 😊
Thank you!
van Straaten liften ,Den Haag aka Schindler
super video :-) deutsche beschrift Schaltplan :-)
thank you!
Those timer relays didn't exist in the 60's either so are a fairly recent upgrade, wonder what they used instead? Maybe a thermal delay based device?
At least at the buildings i oversee we have much much different motor systems than even the typical ones you showed
great video m8
Thank you Nexfero
Isn't the movie "shindlers lift" supose to be in black and white?
I predict that I will be able to understand that drawing in about 2 years time. I've learnt a lot over the past few years, however, I've only just started learning about 3 phase AC induction motors, and I'm not sure how the magnetic fields interact in these rather standard motors, let alone in a DC generator! The system in your video is fascinating, but a little too complex for me!
Hi Michal, I didn't feel that I understood it enough to fully explain it, hence the conclusion I gave at the end. I did try to find out all I could, and I knew the community would fill in the gaps. Every day is a school day!
I could have sworn I saw another vid treating this subject and the explanation was that the small generators were supplying field excitation.
That roar was personal 1:33 ☠️☠️☠️💀💀🏴
It seems like diode banks would make more sense than the motor generator setup. Was it more cost effective or more reliable to have this setup?
I realize this gives three voltages. But ac voltage change is easy with a transformer.
Until just a few years ago, my city still had DC power distribution to run lifts in some buildings.
In minecraft(create mod)i build a lift with seqensed gearshifts and what i think at you can say is the lift motor is running "on time"/its running on a time to exemple if the lift gets a call one floor above its need a speific time to reach the call.Idk if this would help but i just want to say about it.
Ello is me
TheLiftDragon recently posted an old Schindler DC lift that uses the 3 generators, it’s fascinating!!
Yep, I actually went to this place about 3 months ago (same place as LiftDragon), but unfortunately it was out of order, when I went there and it's now LONG TERM out of order (possibly waiting to be modernised). LiftDragon went there about 3 months before I did when it was working. So I did plan to upload a video for it, but probably won't now, and LiftDragon's covered it anyway.
Great video! My question is, how does the lift logic determine whether two calls are one floor apart or many floors apart? How does it know whether to go at high or low speed? I don't understand how this would be done before microprocessors since you would need some kind of subtraction logic.
You don't need subtraction. I don't know how this system actually works but I can make a guess. The selector pushes one way on a switch bank for all the floors below the current position and pushes the other way for floors that are lower. Signals can run in a line through the switches. The call logic could energize a line on the corresponding selector switch where it would energize a "next floor" signal. If the call is further away the next floor switch would reroute the "next floor" signal to a "far floor" bus. Then the currently selected floor switch would route the "next floor" and "far floor" signals into the control logic.
Schindler is the BEST Modern Day Lift Company and they have even Beat Otis in Quality recently.
Maybe in Europe, but in other places, Schindler leaves a lot to be desired
Overpriced,all big brands.
Can't help it, but always must think of the movie Schindlers List when in a Schindlers lift.
That is a normative statement based off your own value judgement. If you were to ask Japanese lift enthusiasts whether they think Schindler is the “best modern day lift company”, they’d think you’re joking.
@@elevatorfilmersg In the UK, Schindler Beats nearly all of the Big Manufacturers. Otis Very recently have gone Ultra Cheap, ThyssenKrupp have been Very Cheap since 2015, Kone's Lifts since 2016 have been going Characterless, Then there's all the 3rd Party Manufacturers (Excluding Orona, Kleemann, Dewhurst and Schaefer) that have been installing Very Cheap Lifts of Very Poor Quality, All assembled by Loads of different Manufacturers such as Raloe, Ziehl Abegg, MP, VEGA and many More. The likes of defunct Manufacturers such as Express and Bennie were a backbone of Lifts in the UK. The only Top Notch Lift Manufacturers in the UK now are Schindler, Dewhurst, Digital Advanced Controls, Orona, Mitsubishi, Fujitec and a few more. Unfortunately the UK doesn't get many Mitsubishi or Fujitec Lifts.
Are there elevators that use AC induction motors to slow down an elevator car by feeding DC current to the AC induction motor?
interesting
these AC motors are alos induction motors which are asynchronous motors, making position control even more sophisticated. They rely on slip to produce torque because of their inductive nature, where a stator field must be cutting (rotating) the rotor cage to produce the cage current for interacting with the stator field, i.e. the stator field rotation speed MUST be faster than the rotor speed for torque production.
The generators are in diffrent sizes(one bigger two smaller)
The pinned comment above explains that the smaller generators energize field windings.
👍👍
What I wounder is why they didn't use a multi current motor in the lift motor. Those was often used in trains and could be trottled in diffrents step. Typicallt with a multiplicable resistor away. Say 3x3 resistors of a total of 9 speeds.
There is actually a dussin ot so ways to make AC controlable. The reformer system was also quite common.
Typicallt most system work by changing the current to the magnitizarion this way the output speed or voltage can be change wirh a very small loss of power...
Well.. small for the time
Wasn't Schindler's Lift a Steven Spielburg movie? ;P
Amazing video.
4:04 It is not even a freight lift/elevator, just a small lift/elevator.
4:08 this is all letting loose
4:11 that is getting worn
So are the two smaller motors not lifting anything, but being used like transformers?
Basically, yes! But it's a motor turning a generator. In this example motor generator x3 for the Dynator control system.
@mrmattandmrchay cool I find it interesting that the smaller motors can turn bigger motors into gens
I ALWAYS LOVE UR VIDEO'S
Hi thank you for the electromech goodness also please can you tell me whats the song at 2.22 called cheers
Thanks for the compliment. The song is Silkworm by Quincas Moreira.
@@mrmattandmrchay thanks dude
From the Philippines
Hi, my second family is from Philippines also (Isabella)
@@mrmattandmrchay i know u like going to a 711?
I think
mrmattandchay, How to wire a dewhurst jumbo button to a battery? Im struggling to connect it.
Hi Lucas, if you send me a photo it (front and back) to mattw.youtube@virginmedia.com then I'll try and help you! :)
I messaged you now.@@mrmattandmrchay
Answered, check your email. Let me know if you need any more help.
Ich möchte Schaltplan kopieren.?
Is this realm of work, kinda whole world for electricians specilizing in DC?
16:40 i think that is if only partially true since it was much easier to control DC back then, all the new stuff with vfd and such are relativly "new" (and reliable in da to day appliances)
18:46 also not really true i don´t think that a commercial building that would need such a lift don´t has 3 phase to it, heck over here in germany it is normal that every household has 3 phase service to it
how would the floor selector work on an elevator with a rear door? one elevator near me has 1, 2, 2R, 3 and 4.
There is a little extra logic added to the floor with 2 doors, to allow the second door to open only on that floor. You just add the second door, the second door motor, and the second retiring cam, which is only enabled with either being on that floor, or by having extra logic, that will only enable it if the rear door button is pressed inside the car, or the call button. depends if you want to allow through operation or have it specifically need to be on request, probably by pressing 2 inside the car, which will flip a relay set to open that door, or entering from 2 pressing 2R, which will do the same with similar relay logic. most common though is both doors open on that floor.
Adding on to @seanBZA comment, if the rear door was at a different level than the front door, then it'll be added as a new floor to the selector. Then the logic of which door opens, I'm guessing can be activated by an extra switch on the wheel - when both front and back should open, or just front or just back. - depending on the position of the lift car, and the activation of this switch.
Yeah - now skilled labor is almost undesired even at cheap prices (if it works perfectly - they won't have a call for return)
Actually I'll expand a bit more on that. At the "boomer" time all these new things were coming out - for example the quadrature (whatever) VCR from 1968. It had to be manually adjusted at startup each time.
Now it's done automatically. We did out job too well! Now the only way for repeat customers is updates (which Now can be deployed as a firmware update) and something that fails
LOL Schindler's lift. 💀