VERY INTERESTING 1930s Otis Elevator Machine Room 

_"If anybody has any sort of information on this system please share it, as I would love to hear."_ *(cracks knuckles)* Here we go, you ready for a splattering of information?! Be sure to grab your popcorn! It's going to be a long one :D Okay, so first things first. The pie plate selector (hereon to be referred to the 6850 selector - because that's what Otis calls it) runs from entirely different principals and mechanics than this selector does. While the resemblance between the two is quite similar (as similar as spinning disks would be). The fundamental operation is very much different. No tech you see on this selector will be in use on a 6850 selector. They are fundamentally incompatible. But I suppose that'd be somewhat obvious to anyone. Now to explain where this selector would be on a product timeline. If we start on the 6850 selector type, we will find the 6104 selector type (ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-EKgd7upy5_U.html) being utilized right alongside it - only in larger buildings of course. The 6104 selector is itself a slight variant of an older model called the 140M. Visually they'll look practically identical, but there are slight variances in crosshead design and stop brush operation and the like. The 140M selector may seem ancient, but we're not there yet! If you take a 140M selector, make it smaller, and even more prehistoric, you end up with the selector you are currently seeing. Quick history lesson, back when semi-automatic elevators were just starting to become a thing - 1910's to 1920's, Otis needed to find a way to get these new machines to stop level with the floor even when no one was near or inside the lift. Very early systems might have used simple switches inside the shaft itself. But these didn't scale well for more complicated systems and adjustment was a pain in the rear and carried with it a fall hazard. So it was decided to make so called 'leveling devices' for use in the motor room. Easy scalability, adjustment, and little fall risk. It was perfect! The first devices were huge and electronically simple - often little more than cams attached to a geared rod. Then as relay control started to take off and the complexity of circuits started growing at an alarming rate, the selector would need to follow suit. And it did. The selector in this video would have been developed in the mid 1920's as elevator complexity started ramping up. It follows the numbering scheme used by the 140M selector. The first one was called a 10S selector (10 Small? Idk), it would have been little more than the cam plates you see on that spinning rod. Then came the 10M (10 Medium?) and then the 11M, 20M, 30M, 40M, etc. until the 140M we see today. Each variant would have added something new to the existing device makeup. I can't say exactly how many variants of this selector there were - information on these kinds of selectors is basically non-existent. But I can tell you they do exist, as evidenced by this video lol. Granted this is the first time I've seen this variant operating in the flesh, so thank you for showing me and in turn, the rest of us that :) Unfortunately, I can't pinpoint what variant you have. I would if I had the SPL sheets for these selectors - and they did have them at one point. (Otis has undocumented 'Spare Parts Leaflets' floating around on the internet for all kinds of stuff they make). But a few years ago, they did a massive purge of their older (1900-1940) documents and they are apparently gone forever. On a side note, this means the selector you see is now on borrowed time. There are essentially no more in production spare parts for it anymore. So the next time it breaks down, uh oh! Anyways, going from memory, I'd say the variant you see before you is a 20M or a 30M type selector. But it's been years since I last saw those SPL's and my memory on the pictorials is fuzzy. Granted you could probably find a nameplate on that selector that would tell you exactly what it is without me having to guess, but I digress... I better end this comment before it gets much longer lol. Anyways, if you're interested in learning how it works, I always recommend with the Otis stuff to try looking for old patents that divulge the purpose and operation of the inventions they create - it really is a treasure trove of information! In your case I found 2 patents that seem to pertain to the selector in the video. (patentimages.storage.googleapis.com/5b/66/d2/c06d3b6d5d258c/US1678423.pdf ) (patentimages.storage.googleapis.com/ed/78/f7/be1e363609e9ee/US1717046.pdf ) The selector in the video doesn't match either completely, but is more an amalgam. The first patent matches regarding the spinning cams and the leveling switches on top, whereas the second patent matches regarding the stopping collars and crosshead panel. If you read both and absorb most of the material, you should be able to surmise how each component relates to each other for this particular selector model! If you need help or have any questions about stuff in the patents, don't hesitate to reach out and I'll see what I can do ;) *Bonus info before I go:* The MG set may look slightly weird having 2 generators on it. Generally speaking that second generator is called an exciter. Basically before the days of static excitation of the DC generator (which would require high power rectifiers - lotsa $$$ back then), the field windings of the generator (which need DC power) were provided with connections to a separate DC generator (the exciter) attached to the same prime mover as the main generator. This enabled the DC generators total flux to be controlled via a separate dc supply for fast, safe, and easy DC hoist motor control. It might seem complicated if you don't understand Ward Leonard motor control, but you should start to get a feel for it once you read some of Otis's patents. Otis in particular also often used this exciter generator to provide the voltage necessary for the elevator controller to function. Thus preventing the possibility of the controller asking for elevator movement without the generator fully started and running! That slate panelboard next the MG set would be for starting and running the MG set - as evidenced by the relays that operated when starting the set at 0:52. Naturally it would need to always be powered so it can start the elevator up at any moment - likely the reason it was placed right next to the electrical service entrance. Clever And that's the end of my comment essay. Wow, if you made it here, congrats! Have a cookie! 🍪

Even though I only have a basic understanding of what I am looking at, I absolutely LOVE seeing machine rooms!

This is what they had to do before programmable microcontrollers. These were the real geniuses.

I just imagine that all men the were involved building this are long gone, but their machine is still there and in operation.

OMG! Amazing machinery, and those contacts on top of the selector - looks like a prehistoric version of the classic bacon slicer selector! Amazing video!

Absolute beauty of electromechanical engineering.

Quite an amazing DC traction machine, relay controller, 2:1 roped,. Yes, the floor selector is awesome! An early version of the pie plate selector. The last controller/rack near the disconnect panel appears to be a DC rectifier or power resistors. DC traction elevators back in that era usually were powered by MG sets, however DC rectifier were not unheard of. And yes it's likely the MG in the video has two generator windings. A 3 phase motor with a dual shaft connected the generators.

Just beautiful. Thanks for sharing this. That's some really cool stuff!

Yeah that is definitely a very early version of the pie selector. And the thing on top looks like to me to be a few pneumatic delay relays probably controlling what contacts on the selector are active so they can’t prematurely activate.

It sounds like a spin from a washing machine spin

Looks like a DC to DC generator.

At which DC voltage the machinery is running? Type plate printings are difficult to read.

JOÃO DAVI de MEND See more

This is a DC MOTOR

I always find myself coming back to these videos

Built to last

Funny thing in my job i often see old systems they run fine and new systems they make a lot of trouble. Not all modern stuff is good and old stuff was not build to alwais fail often so bic companys can sell more!

1930 is crazy👌👌😳😳😳😳😳😳☠️☠️☠️

I love this old technique :)

All mechanical and no computer,

They have one in the Masonic temple in Oregon City. That hasn't been updated, but has been serviced and still works. Try riding on one. You have to manually open the door yourself and there's 2 of them.The first door looks like a normal door like the ones.You find in your hothe one behind.That is a metal door you have to slide open. When you press a plastic black buttons, you can feel the brake release in the car. Literally bounces a little bit when it goes up or down. After that I took the stairs when I needed to go back down.

This is before the days of VFD's and PLC's.

At which DC voltage the motor is running? On the type plate of the generator I could read 45 volts? I guess a little low for this machinery. Perhaps for the exciting machine, not for the armature? But I know that some DC elevator machines are running at rather low voltages, often much less than the AC mains voltage, in the range of 100-200 volts DC.

Check out the book Elevators by Fred Annett(sp). Classic hardwired relay logic. Three-phase ac star-delta starting circuit. DC commutated motor under variable-voltage control.

AMAZING!

0:52 awesome!!

That generator is of a different generation.

What fpm? Also how many floors? Cool machine room btw!

Ist this still in use or just for show? The liftmotor looks Like a DC motor? Greetings from Germany 😊