The selector is connected to the lift car by a toothed steel tape. There would have to be a breakage somewhere for it to go out of synch. There’s also the BTS, a safety switch on the tape hitch that will shut down the lift if the tape should break.
The best part is that now we can fit all of that power switching and logic into a couple of boxes smaller than a desktop computer. This is still a beautiful example of mechanical logic though, a marvel of engineering.
I watch this video at least Once a week, I find myself mesmerized by this control room, but more specifically the floor selector. I find it to be a greatly fascinating technology. Back when everything was analog, that fact that it lasted this long goes to show you that you may be able to beat the efficiency of these old machines, but you certainly can't beat the reliability. Thanks for the uploads, hope to see more in the future.
+Ethan Hi Ethan, sorry I haven't replied yet (and this is 3 months ago now!). Yeah me too, it's what all my videos are about... watching fascinating old lift technology and I've had so many people message me and tell me that old stuff is much more interesting that the new stuff.One day all this will be history, to be seen nowhere except on youtube, so it's important to get as much footage as I can before this happens as a time capsule.
The current drawn on the AC motor side will depend on the load presented on the DC side, so the generators will not draw their full rating continuously. That said, even running idle with no secondary load the generators will still burn up a modest amount of power. I think the main reason the timers aren't fixed is that it isn't just as simple as turning them on when the lift is called. They have to run up to speed first and that involves other circuitry. That and lazy or bad engineers.
RODALCO2007 Apparently this is currently all being ripped out. I have a question regarding the vacuum tubes - I have a very limited understanding of these, but think that these are being used to latch the call buttons somehow? Would they be used for switching?
The glowing valves you can see are hermetically sealed thermal devices with a fixed delay time. They are used to shutdown the generator after no calls registered in the system of that particular lift for a preset time , it used to be about 4 minutes from what i can recall.
at the time this elevator should be very expensive. such engineering and still works with relays, valves, buttons, must have been very well maintained also. ps sorry for english i'm brazilian
I'm so glad modern plc programming is written in basically the same manner the schematics for this old stuff is written. This was done to ease the transition from relay logic to digital.
It's so comprehensible. Visual activity can be logically understood. With solid state there's nothing to look at that signifies anything that may be happening or not happening as it should. Thanks!
Pretty cool, I've looked at some of the early patents to these control systems. One thing that is really cool is the old dispatching systems. Running quickly through the logic makes you realize how much easier life is today with microprocessors. Basically with all the input/outputs being conventional types, you can simply program the microprocessor to give all the up/down/stop/slowdown commands. And if you are wrong, you don't have to re-wire anything, just plug in your laptop! In fact, the distance measurement is completely digital now, (encoder) no need for a driven carriage with discs. Its amazing how complicated elevators really are when you have to design the logic for them.
Definately! ua-cam.com/video/w0Jy805xYJE/v-deo.html see 9:28. This dispatcher is wicked!!! I wanted to experiment with this one, but unfortunately the lift engineer who I was with didn't want all the passenger lifts running up and down as security would have gotten confused in the lobby. It's a shame as technology like this has almost gone! :( I too really like the older designs. Thanks for your comment.
We have an old Otis elevator at my work, I have been in the penthouse for it a couple times when we were trying to figure out how to run some new wiring. Building is from like the 1960-1970s, mechanism appears to sit directly on top of the elevator shaft. Only way up is one of the stairways goes to the room. I always noticed you got near the room you could hear a motor, or something going, I figured it was a vent fan or the relays, think it is probably the generator. This one only does like 4 floors though. Something the other day just got me curious about the gob of relays, etc that make it work. I work on computers so part of me is like just throw a big motor and VFD and some other controls in and this would be a much simpler system. The other part though looks at these and is like that takes a lot of work to setup/program, etc one of these. Where a computer you could just have an encoder, etc say 1,2,3,... and that runs a PLC/VFD and then you can adjust it digitally.
This is an iteresting comparison between Otis and the Westinghouse elevators of the same era. Your DMR video is of higher speed machines but, basically Otis used more mechanics than electronics to control their lifts. The Christmas tree things are known as a type 6850 selector or "pie plate" selector. The 6850 selector os driven by a flat steel tape connected to the lift which then drives a reduction gear box which drives the selector shaft. The contacts that are on the selector tell the lift controls where the elevator is, when a stop needs to be initiated and when to slow down and stop level with the floor, also when it is safe to open the car doors. These lifts are medium speed lifts, on high speed lifts there are other parts to the selector which advance the whole selector panel to allow for a long distance stop. The 6850 selector is a great piece of equipment that is relatively easy to master for the lift mechanic....or was....now lift mechanics seem to watch video screens and scratch their heads quite often...
+Eric Brandt I've seen a couple of videos showing the advancer for longer stopping distances, one was on dieselducy's channel. Facinating, but never seen one over here. I went in a 20 storey Otis motor room once, but I think this was a "geared" machine and took ages to get from G to 20.
The advancer panel was used to control the maximum speed that the lift would run up to according to how far away the next stop was. The amount that the panel extends controls the maximum speed. When a floor has a call in then a contact in the advancer line would go live. As the lift starts, the panel extends until it finds a live contact then the top latches. If the first live contact is far enough away the panel will extend fully and the lift will reach top speed. If the first live contact is close, the panel only extends partly and the maximum speed will be in proportion to that. Even when you are used to seeing them, they are fascinating to watch in action.
Saw a selenium rectifier! That's more like '50s tech... this looks like a product of evolution, in that old and new things get mixed together into 'what works'.
+scowell The rectifier you can see marked BRF is the Brake Coil rectifier, a DC coil is used to energise and lift the brake.A DC coil supply is easier to control using damping capacitors and resistors to control the actual amount of brake shoe lift. As the lift attains levelling speed which is about 15fpm resistance is inserted into the brake coil circuitry to enable the brake ling to FEATHER on the rotating brake drum before the system comes to a halt. If set up correctly it will give a almost sensationless stop.
+Peter Lomas Cool - very interesting stuff. Wish I was in the industry back in the 70s and 80s - I love all this type of stuff. Only problems (as someone has pointed out recently) is you don't have a lot of "fault finding tools" with relays. But on processors you can go back into history to identify faults and mostly make a prediction based on information picked up from the system's memory. However, I don't care, I like to see relays and mechanical devices working :D Very interesting!
+Peter Lomas Thanks! Also, since a selenium rectifier has a relatively high internal resistance, it's not a simple thing to replace it with a modern silicon diode... the circuit impedance would have to be adjusted. There's a similar application in the Leslie 21H speaker cabinet, an electric brake... but it actually puts DC on the motor itself in order to stop the spinning speaker baffle. Uses a thermally-activated time-delay relay (see some of them in this video too) and a selenium rec... the leakage resistance means that the motor creeps slowly when the brake is on. Later Leslies used a 2-speed setup that's completely different. Love old tech!
next time you find one thats about to be demolished or renovated ask the owners if you can help modify the lift so the cool spiral floor selector is at the lobby behind glass so people can enjoy it in action! it would be alot of work to move it but worth it when its completed.
I worked in buildings that all had these types of elevators, the control and drive systems were all replaced with modern equipment and motors, no more motor/generator setups either. What strikes me as odd, is that all the moving parts are covered by guards, nothing like that in the buildings I’m familiar with. The machine room was locked, and that was it, only elevator technicians normally entered those rooms. If I, as building staff needed to enter, I knew well enough not to touch anything for fear of being shocked or crushed. Even elevators that were retrofitted, did not have guards in place, I guess here in Ontario, Canada, our occupational safety laws have not caught up.
In this day and age, it's the claims process of getting money for accidents. If an employee had an injury they can say "my company did not protect me enough by installing guards over the sheaves and cable" and the court would award money to the employee. Unfortunately the day and age of 'common sense' is out the window and now companies need to be seen to be acting safety 'just in case' someone makes a wrong move and injures themselves. I suppose this is not a bad thing as everyone has a better chance of going home uninjured
Lift drive systems have seriously come a long way! Now we are using VVVF and gearless systems. Even the control board has become smaller as well. Also since it is using VVVF there is no need for separate AC/DC generator which means the room is much more silent. Worm gear drive > Gearless AC/DC generator > Variable Voltage Variable Frequency Mechanical relays and vacuum tubes > computerized controls The space needed to house all the equipment is alot too! Nowadays some lifts do not even need a machine room. The only item I saw which still has not changed is the safety gear/overspeed governor.
Fascinating stuff I love older technology at least you can understand it and actually see whats happening . Those glowing tubes look like voltage regulators I think they are full of neon gas the one that was fully lit looked to have nearly the full circuit volts on it may be a burnt feed resistor or shorted cap preventing the generator stop from working.
These lift equipment rooms can be very scary! As a commercial fire alarm & card access tech, I have been in many of them. Some of these DC motors are running over 4000 VDC and often times the guards are removed from the brakes & cable pulleys. I get like a cat in a room full of rocking chairs every time I go into the penthouse and I get really jumpy when the motors click on/off right next to me.
ClusterCracker I am also an access control sys tech guy! I've been caught out by a few motor start ups and jumped, for instance see ua-cam.com/video/ysLenmK3kKw/v-deo.html see 0:33 and 3:02 LOL
mrmattandmrchay Yes, those are small hoist units compared to some I have seen in 50+ floor lifts downtown. It gets really precarious to get at the smoke/heat detectors over the potentially moving at any moment parts. Good videos! The worst was a heat detector in a transformer vault at a school, I had to throw plywood over the switchgear feed ladder and stand over 3 6KV transformers 2 feet from the phase knife switches. Talk about not dropping any screws down lol.
As someone who maintains similar controllers, everyone loves the old stuff, but getting parts and keeping hem running gets harder and harder as years go by
Hey! i am 66 years old not 100 and i can still find my way around that masterpiece of lift engineering. They can throw up some mind blowing problems at times.
They’re not as complicated as they seem. I’ve been an elevator Mechanic for 6 years and maintain a handful of old Otis controllers and selectors like this.
Another nice motor-room vid Matt. I never tire of watching the old 6850 selectors*, seeing the crown snap down and those inquisitive contacts feeling for the pie plate. Did I see some rocking going on there on a few floors, LU and LD a bit too close perhaps? @force311999, it's a bit more complex than a jukebox because there are different types of call to distinguish and place into order, but underneath the selector concept is similar. Although, lift mechanics should be well pleased that there were no floor selectors built like the Seeburg Tormat. *Actually, you need to find a system with advancer panels and get shooting...
I'd like to know how you get power to the cab, and for the control buttons, what must be rather complex. I've never seen in in any of these elevator videos. Brushes along the side rails?
Nope, it's similar than that. Trailing cables (electrical). They go from the motor room, down conduits to the middle of the shaft. Then it's a flexible cable from the shaft, looped down the shaft then back up to the lift car. You can see them on the left here... ua-cam.com/video/mMJsgirJXzM/v-deo.htmlsi=ZGfJIXP-Y3ffjOO_&t=288
At Bombay Otis we had B T machines and if they are still in use you have not shown the selector Ratio and the 62.GC generator time out if all calls are attended it has xmgt or Ert relay times out so the generator is off and provide a stop bracket on the selector shaft so if the tape brakes it will stop and will not damage the selector crosshead.
Hideously over complicated, even back then. Amazing it all actually worked, yet the design, wiring and testing of this 1971 apparatus must have taken the better part of two years.
+Joseph Rotello I agree and I'd love to have been part of designing it also. Elevator relay logic and mechanical logic at its finest! It's amazing what they come up with.
+Joseph Rotello Not complicated at all, with a decent set of wiring diagrams it is all so logical. The art of fault finding is knowing how the system works in the first place. Then a process of elimination,,very high maintenance though.
omg!! But I would have thought it would be blatantly obvious that - an engineer with a few new parts and a bit of labour to get the gen set shutdown working, would pay for itself within days? Is it that the 'knowledge' of how to replace the shutdown circuit to a newer equivalent is unknown, or are Otis just waiting for the customer to realise how much they are paying, then they will place an order to get it sorted?
Vacuum tubes and mechanical switch mechanisms for this. Strongly predates digital. That rotating switch mechanism is an very clever & interesting device. There are also thyratrons in this system.
+norman gates I love these motor rooms and the ideas that various companies came up with to control logic to these lifts - facinates me. You seem to know a bit about this? Just wondering why you would use a vacuum tube instead of using a relay instead? Also thyrathons - not heard of these before? Thanks in advance for any info :)
+mrmattandmrchay The thyratrons are like amplifiers for the relays. They make the relays sense a much smaller current like from a photocell. The rotating switches must be used for the self-leveling system for the elevator cars.
+norman gates, I didn't see any thyratrons, but I did see some diode and triode tubes in the design. Generally, a thyratron has a bright blue glow to them. Thyratrons have a gas in them, instead of a vacuum, that when it becomes ionized, it glows, which is called a Townsend discharge. Those relay coils can easily be ran from a triode, as a thyratron is for heavy current.
You know you have OCD when.... WHY is this so fascinating!! I could watch that rotating relay platform for hours and never get bored. Is the speed controlled by shunt resistors in the DC rotor to vary magnetization and thus slip? Or is this a ward leonard drive???
It’s the Otis UMV (Unit Multi Voltage) system. That’s really a version of Ward Leonard. The output of the generator is controlled by varying the strength of the magnetic field that the rotor revolves in.
7:58 When he carriage finds an active call to initiate a stop could that active call lever be initiated by selecting a floor as well as calling the lift? For example going from Ground floor and selecting floor 5 will open a call lever on the 5th floor bar so that a stop is initiated when the carriages reaches 5th floor bar? Thanks.
See... The promised "EPIC SELECTA MOVIE" - A beginners guide to 1970's relay logic circuits! at 08:25 - hope this answers your question. Yes, for an UP/DOWN button system, there are three call logic circuits per floor, but watch the video as this probably describes it better than I can explain here.
The top rooms in this place can go for around £10000 per night so the electricity cost is small change. During the day the lifts would have quite a high traffic volume so engineer/site would be none the wiser. At night this motor room should silent apart from the odd guest turning up or room service delivery. Not sure if parts for these are easily available bearing in mind they were installed not long after England won the world cup :( I think they plan to replace next year
Sorry, I cannot answer either question. My guess is that the blue-prints/designs would have been submitted worldwide. Whether different countries had their own practices and different ways of doing things, probably.
On these, It looks to be a worm drive on the lift drum, but for other breaking, what do they use, a drum break elsewhere? These works similar to an overhead DC crane in the way they are controlling the motor.
Peter Lomas They're several types. Just the lift gearing is one, as a high ratio worm gear is considered self-locking, but it can slip if jarred or under vibration. Spur, helical, and Herringbone gear sets will back drive, even planetary, so some form of mechanical locking brake is used with hoists. Then you have either electromagnetic drum and disc brakes. The disc brakes, like Stearns or Dings, in the US, are used on the tail end of most drive motors, especially on smaller home elevators. Of course, the drum brakes can be mounted off several shafts, with a clam-shell caliper mounted to grab them, as on overhead cranes of a larger size. They have larger disc brakes similar to this, too. On DC PM motors, you can use regenerative breaking, by shorting the motor leads through a shunt resistor, via a relay. However, that requires the motor to turn, to produce a current like a generator, to work. That is on smaller DC motors though.
+craxd1 The only additional braking system would be the ROPEGRAB, this clamp is mounted in the machine room usually on the machine bedplate and is electrically operated if uncontrolled motion is detected in the system (i.e if the lift is at floor level with the lock circuitry open) and movement is detected normally by pencil sensors or something similar mounted on the lift car.They have only become common in the last 10 years or so as has the Bi-Directional safety gear. This bit of equipment protects the lift from overspeed in the UP direction. Prior to both these introductions the Brake and the conventional safety gear were the means of holding the system. I have NEVER heard of vibration or jarred loading moving a system on a passenger lift.
Peter Lomas Peter, that is what I'm speaking of, the brake holding the system, thus stopping and holding it, in it's spot. If the gearing has a worm drive in it, say have it intermediate, that the motor drives it, then it a pinion gear, next the pinion a bull gear on the drum, that is a safe arrangement, but I have actually watched that arrangement fall, on a set of lifting railroad car rotators, when the brake-motor's brake gave out, and the vibration through the concrete floor was enough to jar it, to get it to inch down. It was a slow fall, but it did it. I think the ratio on the worm was around 40:1. Of course, since elevators are counterweighted, they may not do that as easily. These rotators were a dead 10 ton lift, at each end, with no counterweight. Here, in the US, I saw a photo of one of our express elevators, that used a standard three reduction gear drive, similar to that used on large overhead hoists, which contains a group of plain helical and herringbone gears, that are not self locking, and have a lower gear ratio. I'm thinking that it had a drum brake on it. Of course, these lift and lower at a lot faster speed, and you have a huge motor to get the required HP to drive it over that. The mechanical one-way brake, I think they only added it later on elevators, here, too. That has been a standard on industrial hoists, though, since the 1890s. While I'm on the subject, I almost got stuck in an elevator, yesterday, while at my physicians appointment, and it was a hydraulic lift. Luckily, it didn't move, and the door button worked to get out. I really prefer a wire rope or a chain hoist, even if it is only two floors.
It's a "no" for a number of reasons. The carriage on the back ALSO defines the floor zones (or areas). And if the lift were not to level correctly then the landing doors would be in the wrong position to be opened. One a door is open, OR a lock is not engaged then the lift wouldn't move anyway.
Wow what kind of vacuum tube was that glowing so brightly!??? Didn't look like a rectifier , what the hell!!??? Please let me know the number if it's still possible. I need to look that up, it's killing me to not know?
Steven King I learned about these from "elevatoradjuster" (he had to close his channel - goughlui.com/2015/02/23/opinion-we-say-goodbye-to-elevatoradjuster-youtube/). He did an explanation on them. There are two types, if you look at 2:23 the one on the left is the new type - the LED (or possibly it's a lamp?) goes out when a call is active somewhere. He didn't do a demo on the old type (which is the bright ones that you are referring to. So these are something to do with switching power to circuits when there is an active call. What I don't understand is, well why not just use a relay to do this? I don't have an answer unfortunately, but if you can offer any other info to this component then that would be very interesting! I've seen these in BLUE before and much larger (again, on elevatoradjusters channel - sadly gone!). (Perhaps my friend ***** can help here?)
What happens when the carriage that rises along the pie plate selector looses connection to the cabin or is so out of line that it can't reach the plates any more? How is the elevator stopped in this case? Does it go until the end of the shaft and is stopped there?
The selector tape is attached to the top of car and tensioned usually by a spring mechanism sitting above a tape switch also on the car top. If the tape was to snap or come off wheel in pit or motor room the spring releases and trips the switch stopping the unit as the switch forms part of the safety circuit Refeffed to as a BTS Broken Tape Switch.
Too bad the motor/generator units were making so much noise. I used to live in a building with 3 Otis elevators much like these, and did have access to the machine room since the building manager was my friend. It was someting to experience the logic relays clattering open and closed as the lifts went about their movements.
Mechanical position comparator - five stars! 20% of energy just lost 24/7 in motor-generator unit. This unit maybe is older, than 1971. Vacuum tubes was never used in lift control in Russia. Instead of DC drive and speed regulator, old russian lifts was equipped with multi-speed three phase async motors. Each speed has an independend windings on stator. Position switches was mounted in the shaft and was driven directly by the rails on the cabin when it passes the floor.
+BTraine Ztraine Hi, no I've always been an enthusiast and I've always had a hobbie with designing circuits involving relays and timers.The voiceovers from Chay and me were copying what the guy I was with was saying :) My Otis friend didn;t want his voice on the movie, so me and Chay did it instead! However, if you study this gear for long enough you get to realise how things work and how the design works.I'm currently studying a Schindler motor room design with relays (uploading soon) and sometimes I have a "Eureka" moment!
mrmattandmrchay Hi, and thank you for your interesting videos! Just suscribed to your chan... I wondered, like others, why they didn't changed to Solid-state DC power supply (switching power units are efficient and reliable) even using those generators? But i can understand the money-cost side also. I saw vaccum tubes, valves (a lot of capacitors behind), and a nice glowing VR75 regulator tube (OA3 75v@30mA) What are they used for, in this setup? (Audio music amplifier for the easy-listening entertainment? But i don't think so...) Thanks for sharing!!
+norman gates 3 Phase incoming supply to primary side of transformer, secondary side of transformer is then connected to the control rectifier which converts the supply to DC at about 130 Volts. This is used to supply the main contactors and control relays.
Lewie McNeely The skill set to repair and fully understand all this is disappearing. I bet Otis still have people that could fix it but I suppose any such event would force the lifts to be modernised.
Pretty much anything can be done without a computer. Might not be as quick but it can be done. Solid-state isn't the best sometimes. The old manual deals weren't as rigid about temperature and humidity.
Each Generator has an output of 6 Kwph so that's 24kwph for all 4. If say its 25 pence per kwh that means the generators are burning £144 a day in electric. £144 x 365 days = over £ 52000 a year ! if they have been like that for 10 years that's over half a million pounds! Should of invested in new lifts years ago :)
Actually, I once thought that these discs DID conduct electricity, but they don't. They simply move those contacts up - if you look at the other end of the contact there is a switch. So they copper discs are just there to activate a whole load of switches as it goes around.
Perhaps they are not copper and just metal. I once though they they "completed a circuit" from the contacts that touched them, but I was wrong. I was unaware that these contacts were just arms, and the switches were on the other end. So the discs just push switches at the end of the arms . If the discs were made of any other material then they would wear down.
The discs are manufactured from copper as they have to conduct electricity between the levelling brushes. The 2 brushes either side of the centre of the disk are the doorzone brushes and are insulated from the copper surface of the disk by rubber pads. Move them closer together and you shorten the length of the door opening zone . The other contacts on the ring have carbon tips and control the final levelling and stopping points, the circuit is broken as the contact leaves the disk de-energising contactors 1E 2E etc.
them generators are no longer used, thyristor atarts now, much better them dc gennies took a lot of lookin after, the timers where probably shorted out, forever changin the carbons and dressing the rotor in that motor room somewhere there would have been a stone with a paddle shaped wooden handle, so you could clean the rotor while it was spinning.
+Tony Baines I have done a 4 car group in a day and thats with time to test everything.You are replacing the generator shutdown timer, nothing else affects the circuitry. Usually set to shut down 5 mins after the last call in the system.
+Peter Lomas yep, and start the gennies up when you put a call in, you must admit that there a pain in the arse them gennies, and i seem to recognize your name, did you work at rubax ? or have somthing to do with aljo ?
+Tony Baines No i started with Otis in 1966 as an apprentice, I also did installation and service for Express, retired in 2014. The gennie mod was a doddle because you only actually changed the existing timer for a timerbase and plug in relay so nothing was altered in the rest of the circuitry. Express drawing office would send you all the bits and paperwork for your new connections.
Instead of running DC generators why dont they just replace them with some wtf humongous silicone rectifiers? How much power would each of those generators be using? I imagine each one is kilowatts, they are also surely not designed for 100% duty cycle so surely the wear and tear makes this hack/bodge not worth while?!
Thyristors combined with silicon rectifiers replaced a lot of M-G drives back in the 1970s. There are still a lot of field-controlled M-G systems out there because they are simple to work on and very reliable, i.e. you don't have to worry about a motor control board going out...
Hi. Far from it, these lifts have lasted since the 70s on the original equipment. I'd like to see a modern day lift last 40-50 years or longer. These have now been modernised as the skills engineers have now are based on modern lifts and the skillsets to repair these okd lifts is becoming rare
+Lorenzo Novarro Not complicated at all, extremely reliable and easy to adjust. You only need to follow good maintenance regimes and it will run for decades.
that rotating switch is an absolute masterpiece of engineering, amazing how it all stays in synchronisation.
The selector is connected to the lift car by a toothed steel tape. There would have to be a breakage somewhere for it to go out of synch. There’s also the BTS, a safety switch on the tape hitch that will shut down the lift if the tape should break.
The best part is that now we can fit all of that power switching and logic into a couple of boxes smaller than a desktop computer. This is still a beautiful example of mechanical logic though, a marvel of engineering.
And we can now also fit all that AC -> DC conversion in a similar sized box!
I watch this video at least Once a week, I find myself mesmerized by this control room, but more specifically the floor selector. I find it to be a greatly fascinating technology. Back when everything was analog, that fact that it lasted this long goes to show you that you may be able to beat the efficiency of these old machines, but you certainly can't beat the reliability. Thanks for the uploads, hope to see more in the future.
+Ethan Hi Ethan, sorry I haven't replied yet (and this is 3 months ago now!). Yeah me too, it's what all my videos are about... watching fascinating old lift technology and I've had so many people message me and tell me that old stuff is much more interesting that the new stuff.One day all this will be history, to be seen nowhere except on youtube, so it's important to get as much footage as I can before this happens as a time capsule.
The current drawn on the AC motor side will depend on the load presented on the DC side, so the generators will not draw their full rating continuously. That said, even running idle with no secondary load the generators will still burn up a modest amount of power. I think the main reason the timers aren't fixed is that it isn't just as simple as turning them on when the lift is called. They have to run up to speed first and that involves other circuitry. That and lazy or bad engineers.
Big Clive? OMG! Love your UA-cam channel!
Masterpieces of electromechanical engineering. Interesting to see vacuum tubes
RODALCO2007 Apparently this is currently all being ripped out. I have a question regarding the vacuum tubes - I have a very limited understanding of these, but think that these are being used to latch the call buttons somehow? Would they be used for switching?
The glowing valves you can see are hermetically sealed thermal devices with a fixed delay time. They are used to shutdown the generator after no calls registered in the system of that particular lift for a preset time , it used to be about 4 minutes from what i can recall.
Another masterpiece is mechanical calculators!
Would hate to think how many selector tapes, broken LV switches and busted PI plates I did in my 40 year career!
That Synchronized rotary limit switch was pretty cool. 12 story building you are in mate.
at the time this elevator should be very expensive. such engineering and still works with relays, valves, buttons, must have been very well maintained also.
ps sorry for english i'm brazilian
I'm so glad modern plc programming is written in basically the same manner the schematics for this old stuff is written. This was done to ease the transition from relay logic to digital.
Wow really neat old buttons I also like the old fasioned indicator inside
It's so comprehensible. Visual activity can be logically understood. With solid state there's nothing to look at that signifies anything that may be happening or not happening as it should. Thanks!
Pretty cool, I've looked at some of the early patents to these control systems. One thing that is really cool is the old dispatching systems. Running quickly through the logic makes you realize how much easier life is today with microprocessors. Basically with all the input/outputs being conventional types, you can simply program the microprocessor to give all the up/down/stop/slowdown commands. And if you are wrong, you don't have to re-wire anything, just plug in your laptop! In fact, the distance measurement is completely digital now, (encoder) no need for a driven carriage with discs. Its amazing how complicated elevators really are when you have to design the logic for them.
Definately! ua-cam.com/video/w0Jy805xYJE/v-deo.html see 9:28. This dispatcher is wicked!!! I wanted to experiment with this one, but unfortunately the lift engineer who I was with didn't want all the passenger lifts running up and down as security would have gotten confused in the lobby. It's a shame as technology like this has almost gone! :(
I too really like the older designs. Thanks for your comment.
We have an old Otis elevator at my work, I have been in the penthouse for it a couple times when we were trying to figure out how to run some new wiring. Building is from like the 1960-1970s, mechanism appears to sit directly on top of the elevator shaft. Only way up is one of the stairways goes to the room. I always noticed you got near the room you could hear a motor, or something going, I figured it was a vent fan or the relays, think it is probably the generator. This one only does like 4 floors though. Something the other day just got me curious about the gob of relays, etc that make it work.
I work on computers so part of me is like just throw a big motor and VFD and some other controls in and this would be a much simpler system. The other part though looks at these and is like that takes a lot of work to setup/program, etc one of these. Where a computer you could just have an encoder, etc say 1,2,3,... and that runs a PLC/VFD and then you can adjust it digitally.
This is an iteresting comparison between Otis and the Westinghouse elevators of the same era. Your DMR video is of higher speed machines but, basically Otis used more mechanics than electronics to control their lifts. The Christmas tree things are known as a type 6850 selector or "pie plate" selector. The 6850 selector os driven by a flat steel tape connected to the lift which then drives a reduction gear box which drives the selector shaft. The contacts that are on the selector tell the lift controls where the elevator is, when a stop needs to be initiated and when to slow down and stop level with the floor, also when it is safe to open the car doors. These lifts are medium speed lifts, on high speed lifts there are other parts to the selector which advance the whole selector panel to allow for a long distance stop. The 6850 selector is a great piece of equipment that is relatively easy to master for the lift mechanic....or was....now lift mechanics seem to watch video screens and scratch their heads quite often...
+Eric Brandt I've seen a couple of videos showing the advancer for longer stopping distances, one was on dieselducy's channel. Facinating, but never seen one over here. I went in a 20 storey Otis motor room once, but I think this was a "geared" machine and took ages to get from G to 20.
The advancer panel was used to control the maximum speed that the lift would run up to according to how far away the next stop was. The amount that the panel extends controls the maximum speed. When a floor has a call in then a contact in the advancer line would go live. As the lift starts, the panel extends until it finds a live contact then the top latches. If the first live contact is far enough away the panel will extend fully and the lift will reach top speed. If the first live contact is close, the panel only extends partly and the maximum speed will be in proportion to that.
Even when you are used to seeing them, they are fascinating to watch in action.
Saw a selenium rectifier! That's more like '50s tech... this looks like a product of evolution, in that old and new things get mixed together into 'what works'.
+scowell Cool, is that the thing that looks like an old aerial that reduces voltages? What part of the video? (mm:ss?)
+mrmattandmrchay Big square finned gray thing at 03:59... old-timey rectifier diode. If you burn one up, don't inhale... selenium bad for you!
+scowell The rectifier you can see marked BRF is the Brake Coil rectifier, a DC coil is used to energise and lift the brake.A DC coil supply is easier to control using damping capacitors and resistors to control the actual amount of brake shoe lift. As the lift attains levelling speed which is about 15fpm resistance is inserted into the brake coil circuitry to enable the brake ling to FEATHER on the rotating brake drum before the system comes to a halt. If set up correctly it will give a almost sensationless stop.
+Peter Lomas Cool - very interesting stuff. Wish I was in the industry back in the 70s and 80s - I love all this type of stuff. Only problems (as someone has pointed out recently) is you don't have a lot of "fault finding tools" with relays. But on processors you can go back into history to identify faults and mostly make a prediction based on information picked up from the system's memory. However, I don't care, I like to see relays and mechanical devices working :D Very interesting!
+Peter Lomas Thanks! Also, since a selenium rectifier has a relatively high internal resistance, it's not a simple thing to replace it with a modern silicon diode... the circuit impedance would have to be adjusted. There's a similar application in the Leslie 21H speaker cabinet, an electric brake... but it actually puts DC on the motor itself in order to stop the spinning speaker baffle. Uses a thermally-activated time-delay relay (see some of them in this video too) and a selenium rec... the leakage resistance means that the motor creeps slowly when the brake is on. Later Leslies used a 2-speed setup that's completely different. Love old tech!
My god you dont want a bad connection in that lot. Im surprised they could even wire it up impressed
Beautiful selectors 😳❤️️😍👍🏽
+Leonardo Rosado I agree. Probably the most interesting to watch out of all the manufacturers.
That's some cool stuff right there.
next time you find one thats about to be demolished or renovated ask the owners if you can help modify the lift so the cool spiral floor selector is at the lobby behind glass so people can enjoy it in action! it would be alot of work to move it but worth it when its completed.
I worked in buildings that all had these types of elevators, the control and drive systems were all replaced with modern equipment and motors, no more motor/generator setups either. What strikes me as odd, is that all the moving parts are covered by guards, nothing like that in the buildings I’m familiar with. The machine room was locked, and that was it, only elevator technicians normally entered those rooms. If I, as building staff needed to enter, I knew well enough not to touch anything for fear of being shocked or crushed. Even elevators that were retrofitted, did not have guards in place, I guess here in Ontario, Canada, our occupational safety laws have not caught up.
In this day and age, it's the claims process of getting money for accidents. If an employee had an injury they can say "my company did not protect me enough by installing guards over the sheaves and cable" and the court would award money to the employee. Unfortunately the day and age of 'common sense' is out the window and now companies need to be seen to be acting safety 'just in case' someone makes a wrong move and injures themselves. I suppose this is not a bad thing as everyone has a better chance of going home uninjured
Is there possibility to see the schematics of this (or other relay-based) lift controller ?
The kid’s voice over is hilarious!
“”I want to be an lift engineer when I grow up dad dee.......NOT!!!”
The kid's already a sarcasm engineer ;)
Cracking video, what a machine room. Shame it's probably gone now!
Lift drive systems have seriously come a long way!
Now we are using VVVF and gearless systems. Even the control board has become smaller as well. Also since it is using VVVF there is no need for separate AC/DC generator which means the room is much more silent.
Worm gear drive > Gearless
AC/DC generator > Variable Voltage Variable Frequency
Mechanical relays and vacuum tubes > computerized controls
The space needed to house all the equipment is alot too! Nowadays some lifts do not even need a machine room.
The only item I saw which still has not changed is the safety gear/overspeed governor.
The first gearless lifts were actually installed in 1901.
Fascinating stuff I love older technology at least you can understand it and actually see whats happening . Those glowing tubes look like voltage regulators I think they are full of neon gas the one that was fully lit looked to have nearly the full circuit volts on it may be a burnt feed resistor or shorted cap preventing the generator stop from working.
If the generator runs 24H/Day the brushes must be wearing quick out.
These lift equipment rooms can be very scary! As a commercial fire alarm & card access tech, I have been in many of them. Some of these DC motors are running over 4000 VDC and often times the guards are removed from the brakes & cable pulleys. I get like a cat in a room full of rocking chairs every time I go into the penthouse and I get really jumpy when the motors click on/off right next to me.
ClusterCracker I am also an access control sys tech guy! I've been caught out by a few motor start ups and jumped, for instance see ua-cam.com/video/ysLenmK3kKw/v-deo.html see 0:33 and 3:02 LOL
mrmattandmrchay
Yes, those are small hoist units compared to some I have seen in 50+ floor lifts downtown. It gets really precarious to get at the smoke/heat detectors over the potentially moving at any moment parts. Good videos!
The worst was a heat detector in a transformer vault at a school, I had to throw plywood over the switchgear feed ladder and stand over 3 6KV transformers 2 feet from the phase knife switches. Talk about not dropping any screws down lol.
4kV? I thought most of them were 230 or 400v. I once saw some hoists that ran on 120VDC.
A few too many zeros there! The 415vac supply was the highest voltage, but that needed to be treated with respect…easily lethal.
have you ever been caught by mantenince just kind of doing your own thing in one of those motor/control rooms?
God that's just incredible!
Amazing explanaition
Did you have the electrical diagram for this type of elevators
Great video!
Fantastic video, they sure dont make them like this anymore :(
+Jared Caudill The video or the lifts? Haha I know what you mean! Thanks for the comment
As someone who maintains similar controllers, everyone loves the old stuff, but getting parts and keeping hem running gets harder and harder as years go by
That cork screw thing in the cabinet is the floor leveller.
Hey! i am 66 years old not 100 and i can still find my way around that masterpiece of lift engineering. They can throw up some mind blowing problems at times.
Now time to build a lift in Roblox Studio...
They’re not as complicated as they seem. I’ve been an elevator Mechanic for 6 years and maintain a handful of old Otis controllers and selectors like this.
Is possible to replace dc generator with full bridge rectifier(may need other parts also) without modifying other stuff?
I love your videos man!
Another nice motor-room vid Matt. I never tire of watching the old 6850 selectors*, seeing the crown snap down and those inquisitive contacts feeling for the pie plate.
Did I see some rocking going on there on a few floors, LU and LD a bit too close perhaps?
@force311999, it's a bit more complex than a jukebox because there are different types of call to distinguish and place into order, but underneath the selector concept is similar. Although, lift mechanics should be well pleased that there were no floor selectors built like the Seeburg Tormat.
*Actually, you need to find a system with advancer panels and get shooting...
I'd like to know how you get power to the cab, and for the control buttons, what must be rather complex. I've never seen in in any of these elevator videos. Brushes along the side rails?
Nope, it's similar than that. Trailing cables (electrical). They go from the motor room, down conduits to the middle of the shaft. Then it's a flexible cable from the shaft, looped down the shaft then back up to the lift car. You can see them on the left here... ua-cam.com/video/mMJsgirJXzM/v-deo.htmlsi=ZGfJIXP-Y3ffjOO_&t=288
that tube looks hot
At Bombay Otis we had B T machines and if they are still in use you have not shown the selector Ratio and the 62.GC generator time out if all calls are attended it has xmgt or Ert relay times out so the generator is off and provide a stop bracket on the selector shaft so if the tape brakes it will stop and will not damage the selector crosshead.
Incredible!
+Bertold Roux Thanks
Hideously over complicated, even back then. Amazing it all actually worked, yet the design, wiring and testing of this 1971 apparatus must have taken the better part of two years.
+Joseph Rotello I agree and I'd love to have been part of designing it also. Elevator relay logic and mechanical logic at its finest! It's amazing what they come up with.
+Joseph Rotello Obviously a product of evolution!
+Joseph Rotello Not complicated at all, with a decent set of wiring diagrams it is all so logical. The art of fault finding is knowing how the system works in the first place. Then a process of elimination,,very high maintenance though.
The design evolved over a long period but the installation and testing wasn’t anything like two years, more like months.
omg!!
But I would have thought it would be blatantly obvious that - an engineer with a few new parts and a bit of labour to get the gen set shutdown working, would pay for itself within days? Is it that the 'knowledge' of how to replace the shutdown circuit to a newer equivalent is unknown, or are Otis just waiting for the customer to realise how much they are paying, then they will place an order to get it sorted?
very very awesome video..thank you..enjoy it...
+Erica Burns cool thanks for your comment
Talk about a mechanical nightmare !! It will make me think twice before using an elevator again !!
Have you any idea of these lifts have been modernized?
I do have any idea, and I can verify that yes, they have been modernised unfortunately :/ :/
Very sad, but it must have cost a fortune to keep those beasts running! Wouldnt have wanted to see the electric bill :P
thanks :)
Elegant!
Vacuum tubes and mechanical switch mechanisms for this. Strongly predates digital. That rotating switch mechanism is an very clever & interesting device. There are also thyratrons in this system.
+norman gates I love these motor rooms and the ideas that various companies came up with to control logic to these lifts - facinates me. You seem to know a bit about this? Just wondering why you would use a vacuum tube instead of using a relay instead? Also thyrathons - not heard of these before? Thanks in advance for any info :)
+mrmattandmrchay The thyratrons are like amplifiers for the relays. They make the relays sense a much smaller current like from a photocell. The rotating switches must be used for the self-leveling system for the elevator cars.
+norman gates, I didn't see any thyratrons, but I did see some diode and triode tubes in the design. Generally, a thyratron has a bright blue glow to them. Thyratrons have a gas in them, instead of a vacuum, that when it becomes ionized, it glows, which is called a Townsend discharge. Those relay coils can easily be ran from a triode, as a thyratron is for heavy current.
+craxd1 the number 2050 at the tube socket indicates a thyratron. I found that out in a tube manual.
You know you have OCD when.... WHY is this so fascinating!! I could watch that rotating relay platform for hours and never get bored. Is the speed controlled by shunt resistors in the DC rotor to vary magnetization and thus slip? Or is this a ward leonard drive???
Ward Leonard system.
It’s the Otis UMV (Unit Multi Voltage) system. That’s really a version of Ward Leonard. The output of the generator is controlled by varying the strength of the magnetic field that the rotor revolves in.
7:58 When he carriage finds an active call to initiate a stop could that active call lever be initiated by selecting a floor as well as calling the lift? For example going from Ground floor and selecting floor 5 will open a call lever on the 5th floor bar so that a stop is initiated when the carriages reaches 5th floor bar? Thanks.
See...
The promised "EPIC SELECTA MOVIE" - A beginners guide to 1970's relay logic circuits!
at 08:25 - hope this answers your question.
Yes, for an UP/DOWN button system, there are three call logic circuits per floor, but watch the video as this probably describes it better than I can explain here.
Espectacular!! buen trabajo me gusta mucho.
The top rooms in this place can go for around £10000 per night so the electricity cost is small change. During the day the lifts would have quite a high traffic volume so engineer/site would be none the wiser. At night this motor room should silent apart from the odd guest turning up or room service delivery. Not sure if parts for these are easily available bearing in mind they were installed not long after England won the world cup :( I think they plan to replace next year
Where was the control equipment made? Would there be big differences in practice between different countries or regions?
Sorry, I cannot answer either question. My guess is that the blue-prints/designs would have been submitted worldwide. Whether different countries had their own practices and different ways of doing things, probably.
Это круто ламповый лифт!!! Интересно сколько лет спецу который его обслуживает?
On these, It looks to be a worm drive on the lift drum, but for other breaking, what do they use, a drum break elsewhere? These works similar to an overhead DC crane in the way they are controlling the motor.
+craxd1 What other form of braking would you be looking for on a geared machine
Peter Lomas
They're several types. Just the lift gearing is one, as a high ratio worm gear is considered self-locking, but it can slip if jarred or under vibration. Spur, helical, and Herringbone gear sets will back drive, even planetary, so some form of mechanical locking brake is used with hoists. Then you have either electromagnetic drum and disc brakes. The disc brakes, like Stearns or Dings, in the US, are used on the tail end of most drive motors, especially on smaller home elevators. Of course, the drum brakes can be mounted off several shafts, with a clam-shell caliper mounted to grab them, as on overhead cranes of a larger size. They have larger disc brakes similar to this, too.
On DC PM motors, you can use regenerative breaking, by shorting the motor leads through a shunt resistor, via a relay. However, that requires the motor to turn, to produce a current like a generator, to work. That is on smaller DC motors though.
+craxd1 The only additional braking system would be the ROPEGRAB, this clamp is mounted in the machine room usually on the machine bedplate and is electrically operated if uncontrolled motion is detected in the system (i.e if the lift is at floor level with the lock circuitry open) and movement is detected normally by pencil sensors or something similar mounted on the lift car.They have only become common in the last 10 years or so as has the Bi-Directional safety gear. This bit of equipment protects the lift from overspeed in the UP direction. Prior to both these introductions the Brake and the conventional safety gear were the means of holding the system. I have NEVER heard of vibration or jarred loading moving a system on a passenger lift.
Peter Lomas
Peter, that is what I'm speaking of, the brake holding the system, thus stopping and holding it, in it's spot.
If the gearing has a worm drive in it, say have it intermediate, that the motor drives it, then it a pinion gear, next the pinion a bull gear on the drum, that is a safe arrangement, but I have actually watched that arrangement fall, on a set of lifting railroad car rotators, when the brake-motor's brake gave out, and the vibration through the concrete floor was enough to jar it, to get it to inch down. It was a slow fall, but it did it. I think the ratio on the worm was around 40:1. Of course, since elevators are counterweighted, they may not do that as easily. These rotators were a dead 10 ton lift, at each end, with no counterweight.
Here, in the US, I saw a photo of one of our express elevators, that used a standard three reduction gear drive, similar to that used on large overhead hoists, which contains a group of plain helical and herringbone gears, that are not self locking, and have a lower gear ratio. I'm thinking that it had a drum brake on it. Of course, these lift and lower at a lot faster speed, and you have a huge motor to get the required HP to drive it over that.
The mechanical one-way brake, I think they only added it later on elevators, here, too. That has been a standard on industrial hoists, though, since the 1890s.
While I'm on the subject, I almost got stuck in an elevator, yesterday, while at my physicians appointment, and it was a hydraulic lift. Luckily, it didn't move, and the door button worked to get out. I really prefer a wire rope or a chain hoist, even if it is only two floors.
Man thats is crazy stuff
Loving it though, but this installation has been modernised! :(
So a set screw loosens up on that whirlybob and somebody gets cut in two when the elevator suddenly thinks the door gate is a few feet lower...?
It's a "no" for a number of reasons. The carriage on the back ALSO defines the floor zones (or areas). And if the lift were not to level correctly then the landing doors would be in the wrong position to be opened. One a door is open, OR a lock is not engaged then the lift wouldn't move anyway.
Wow what kind of vacuum tube was that glowing so brightly!??? Didn't look like a rectifier , what the hell!!??? Please let me know the number if it's still possible. I need to look that up, it's killing me to not know?
Steven King I learned about these from "elevatoradjuster" (he had to close his channel - goughlui.com/2015/02/23/opinion-we-say-goodbye-to-elevatoradjuster-youtube/). He did an explanation on them. There are two types, if you look at 2:23 the one on the left is the new type - the LED (or possibly it's a lamp?) goes out when a call is active somewhere. He didn't do a demo on the old type (which is the bright ones that you are referring to. So these are something to do with switching power to circuits when there is an active call.
What I don't understand is, well why not just use a relay to do this? I don't have an answer unfortunately, but if you can offer any other info to this component then that would be very interesting! I've seen these in BLUE before and much larger (again, on elevatoradjusters channel - sadly gone!). (Perhaps my friend ***** can help here?)
Great thanks! Nice video.
+Steven King looks like a neon indicator
Cool!
+Steven King The glowing tube most likely a neon filled voltage regulator tube.
What happens when the carriage that rises along the pie plate selector looses connection to the cabin or is so out of line that it can't reach the plates any more? How is the elevator stopped in this case? Does it go until the end of the shaft and is stopped there?
The selector tape is attached to the top of car and tensioned usually by a spring mechanism sitting above a tape switch also on the car top. If the tape was to snap or come off wheel in pit or motor room the spring releases and trips the switch stopping the unit as the switch forms part of the safety circuit Refeffed to as a BTS Broken Tape Switch.
I think they should replace those old motor-generator sets with some modern mercury arc rectifiers!
danielrichardbond Or using a silicon-controlled rectifier
Too bad the motor/generator units were making so much noise. I used to live in a building with 3 Otis elevators much like these, and did have access to the machine room since the building manager was my friend. It was someting to experience the logic relays clattering open and closed as the lifts went about their movements.
Seriously runs rotary converters?
Essentially, an old telephone exchange.
Does the selector also help the car line up accurately with the floor?
That’s one it’s main functions
2:26 what are those 2 things?
Mechanical position comparator - five stars! 20% of energy just lost 24/7 in motor-generator unit. This unit maybe is older, than 1971. Vacuum tubes was never used in lift control in Russia. Instead of DC drive and speed regulator, old russian lifts was equipped with multi-speed three phase async motors. Each speed has an independend windings on stator. Position switches was mounted in the shaft and was driven directly by the rails on the cabin when it passes the floor.
A valved lift , what are the thermionic valves for.
Gary Hunter Where in the video is this please?
mrmattandmrchay
I too am curious about function of these valves. They are at 13:53, the glowing orange tubes. Very interesting video!
Did you use to work in the industry??? You seem to know your way around that equipment
+BTraine Ztraine Hi, no I've always been an enthusiast and I've always had a hobbie with designing circuits involving relays and timers.The voiceovers from Chay and me were copying what the guy I was with was saying :) My Otis friend didn;t want his voice on the movie, so me and Chay did it instead! However, if you study this gear for long enough you get to realise how things work and how the design works.I'm currently studying a Schindler motor room design with relays (uploading soon) and sometimes I have a "Eureka" moment!
mrmattandmrchay Hi, and thank you for your interesting videos! Just suscribed to your chan... I wondered, like others, why they didn't changed to Solid-state DC power supply (switching power units are efficient and reliable) even using those generators? But i can understand the money-cost side also.
I saw vaccum tubes, valves (a lot of capacitors behind), and a nice glowing VR75 regulator tube (OA3 75v@30mA) What are they used for, in this setup? (Audio music amplifier for the easy-listening entertainment? But i don't think so...)
Thanks for sharing!!
+yahnsolo The selenium rectifier and glowing regulator tube (with caps) may be a power supply to run the relays.
+norman gates 3 Phase incoming supply to primary side of transformer, secondary side of transformer is then connected to the control rectifier which converts the supply to DC at about 130 Volts. This is used to supply the main contactors and control relays.
Do the lifts still exist?
These are gone, modernised about 2-3 years after I made this video.
I think there is a wire inside the copper disks
Can't they use rectifier to convert AC to DC?
Interesting controllers
Archaic, but interesting!
That was very interesting. But I can a fire hazard from old wiring.I would rather have mechanical then electronic.
chay would make a good lift engineer.
are the motors 208 or 480 3 phase
415v 3-phase
i never seen 415volt is it special
415V 3 Phase is the UK STANDARD. 240 VAC on each phase.
Vacuum tubes! :D
SE VOCÊ QUE É ELETRICISTA E SABE MONTAR UM COMANDO, QUE TAL MONTAR ESSE.
.genial....analoge mechanik works always.....
All I can say is God help whoever has to rewire one after a good short!
Lewie McNeely The skill set to repair and fully understand all this is disappearing. I bet Otis still have people that could fix it but I suppose any such event would force the lifts to be modernised.
Like wireless maybe??
It blows my mind how a bunch of mechanical relays and switches could perform the necessary logic to efficiently operate a bank of elevators.
Pretty much anything can be done without a computer. Might not be as quick but it can be done. Solid-state isn't the best sometimes. The old manual deals weren't as rigid about temperature and humidity.
+jb0177 That's what I like about old motor rooms ;)
good
thanks :)
ja passei horas na frente desse trem.
Each Generator has an output of 6 Kwph so that's 24kwph for all 4. If say its 25 pence per kwh that means the generators are burning £144 a day in electric. £144 x 365 days = over £ 52000 a year ! if they have been like that for 10 years that's over half a million pounds! Should of invested in new lifts years ago :)
I think they use copper because it conducts electricity
Actually, I once thought that these discs DID conduct electricity, but they don't. They simply move those contacts up - if you look at the other end of the contact there is a switch. So they copper discs are just there to activate a whole load of switches as it goes around.
Then how come they used copper as the material, they don't conduct electricity, then the disks can be any material
Perhaps they are not copper and just metal. I once though they they "completed a circuit" from the contacts that touched them, but I was wrong. I was unaware that these contacts were just arms, and the switches were on the other end. So the discs just push switches at the end of the arms . If the discs were made of any other material then they would wear down.
The discs are manufactured from copper as they have to conduct electricity between the levelling brushes. The 2 brushes either side of the centre of the disk are the doorzone brushes and are insulated from the copper surface of the disk by rubber pads. Move them closer together and you shorten the length of the door opening zone . The other contacts on the ring have carbon tips and control the final levelling and stopping points, the circuit is broken as the contact leaves the disk de-energising contactors 1E 2E etc.
Lifts in the U.S. A. are called elevators.
+MIKE CHIESA bruh, do u even elevate?
+Thee Adjudicator yes
great job but it took you a LONG time to make/edit
them generators are no longer used, thyristor atarts now, much better them dc gennies took a lot of lookin after, the timers where probably shorted out, forever changin the carbons and dressing the rotor in that motor room somewhere there would have been a stone with a paddle shaped wooden handle, so you could clean the rotor while it was spinning.
+Tony Baines Fit a new timer with associated wiring is about a 1HR job.
+Peter Lomas nope not that simple on a duplex.
+Tony Baines I have done a 4 car group in a day and thats with time to test everything.You are replacing the generator shutdown timer, nothing else affects the circuitry. Usually set to shut down 5 mins after the last call in the system.
+Peter Lomas yep, and start the gennies up when you put a call in, you must admit that there a pain in the arse them gennies, and i seem to recognize your name, did you work at rubax ? or have somthing to do with aljo ?
+Tony Baines No i started with Otis in 1966 as an apprentice, I also did installation and service for Express, retired in 2014. The gennie mod was a doddle because you only actually changed the existing timer for a timerbase and plug in relay so nothing was altered in the rest of the circuitry. Express drawing office would send you all the bits and paperwork for your new connections.
😯😯😯😯
curwent??
I think the motors are QUIET
ESSE ELEVADOR E MUITO VELHO
Instead of running DC generators why dont they just replace them with some wtf humongous silicone rectifiers? How much power would each of those generators be using? I imagine each one is kilowatts, they are also surely not designed for 100% duty cycle so surely the wear and tear makes this hack/bodge not worth while?!
Thyristors combined with silicon rectifiers replaced a lot of M-G drives back in the 1970s. There are still a lot of field-controlled M-G systems out there because they are simple to work on and very reliable, i.e. you don't have to worry about a motor control board going out...
Really (1 million views) just why.
Ah, that was my total video views in 2013. Right now I'm nearly at 6 million "total" video views across my channel :)
mrmattandmrchay Oh I thought you were doing it to make your vid higher up on searches. They fixed that now anyway.
As for me, too complicated mechanical scheme. Perhaps, it is not very reliable.
Hi. Far from it, these lifts have lasted since the 70s on the original equipment. I'd like to see a modern day lift last 40-50 years or longer. These have now been modernised as the skills engineers have now are based on modern lifts and the skillsets to repair these okd lifts is becoming rare
+Lorenzo Novarro Not complicated at all, extremely reliable and easy to adjust. You only need to follow good maintenance regimes and it will run for decades.
Did the council force them to modernise them?