Rotary converter that transforms AC electricity to DC. Converter is in MTA's Substation #13. More information and photos of the substation where it resides on my blog post. www.geekygirlen...
For many years this substation was a problem for the television shows originating from the Ed Sullivan theater right next door, as the magnetic fields would interfere with the television camera pickup tubes, causing the picture to bend or wiggle. Camera makers had to specially shield the cameras to be used there, and the cameras were kept some distance from the back wall of the stage that is right next to the substation building.
My brother once filmed a particular type of Dutch train (called the Koploper, or Headrunner in English) with an older type of videocamera that still used a CRT-style viewfinder. It was his idea to get a good recording of the chopper installation on the train so he was sitting right next to the vent of the electronics cases where the sound was the most clear and easiest to hear. Upon the main switch in the train closing to engage the chopper the image in his viewfinder immediately distorted massively. :P Interesting story about the videocamera's. As much as I like to read about older electronics, these kinds of problems are not ones I probably would've liked to deal with, though on the other hands, there's also no way to tell for sure since I would not have known any better should I have been born earlier.
Beautiful machine. Hard to believe this was necessary before semiconductor rectifiers were invented! Also, thanks for including your blog link in the description. I really enjoyed reading about your visit to the station and the pictures.
The big advantage to the rotary converter was that itv was a rotary CONVERTER. You could convert AC to DC or DC to AC, and could start this beast off of the DC or the AC bus. Although not a big deal today, turn of the century NYC had a lot of DC and 25 cycle AC networks, and needed the ability to transfer power to where the need was. Today, it is just convert the incoming 60 cycle current to the 600VDC needed by the MTA.
I saw another one of these being started by track voltage (DC) and then switched over to AC-DC when it became synchronous with the 25 Hz AC supply. If it ain't broke, don't fix it.
A giant line start synchronous motor with an integrated DC generator. Synchronous motors themselves, despite their large size and low starting torque, are still in use for some applications as they are extremely efficient and can provide power factor correction for an entire plant when set up properly.
Its a synchronous rectifier. This principle is used today, but mechanical contacts is just replaced with IGBT, driver motor is replaced by microcontroller.
Modern solid state rectifiers and inverters can operate at plus/minus 500 kv for long distance DC power transmission lines. Absolutely amazing engineering and technology.
We had these on the Southern Region of British Railways as was, the buildings are still there, huge doors allowed for exchange of the major parts if needed. The Rotaries made a howling sound on load, but have all gone now alas ! Then came remote control ones, controlled by staff at a manned example. Then in the 20's Mercury Arcs were used, in lovely art deco buildings, they'd glow blue when a train was taking power. This meant the SR could electrify miles of track right out into the country and became the mostly commuter line it is now. Then the much less interesting steel tank types appeared in the 50's. Newer installations used germanium or silicone rectifier diodes. It's this equipment that resides in even the old Rotary subs. Vandalism meant we had to brick up the windows years ago, so they don't look right now. All this supplied 660V, later 750V DC to our top - contact 3rd rail. Most of the old kit went when the new plastic, souless, computer controlled MU stock arrived. They drew WAY too much juice for the old 'uns to cope with. They don't make the right Electric MU sounds either, ticking compressors, growling motors, well you know ! :-) As for running in snow, forget it !
There's a TPH near me on the LSWR by FNN. The windows shone out mauve light with high order humming when a train was accelerating away from FNB. Bricked-up now, solid state, quiet. The units make more noise, whiney & moaning.
You should tell everyone that back in the day the AC 11,000 volts did not come from the city grid, Rather from there own power station on the west side 58th and 59th Streets and Eleventh and Twelfth Avenues, Big Boilers burned Cole that was an amazing place to walk around. And boy do I remember being given the tour of the converter station at I think it was 53st. just off 5th ave I think. when they would bring online more converters for the PM rush hour. My Dad and I would stand for hours just looking. The LIRR had converter stations, but they used those big Glass vapor Arc tubes that took 3 phase AC also at 11,000 volts with the big blue glow from the arc. I got the chance to visit quit a few of them in Queens, and out on the Island. I still preferred to watch and listen to the Motor converters. Thank you for posting this.
That must have been quite an experience! I miss the days when I was a kid, and my dad brought me to the plant where he used to work. Thanks for sharing!
Hello David Irwin, and tech friends. First off. Thank you Geeky Girl Engineer. This is a link to a PDF file of a book of the Power station with photos tech drawing and a wealth of info about the subway power distribution system that dates back to the 1900's. I had that book in my possession back when I was a jr high student back in the 60's and would carry that big heavy hardcover book every where I went exploring the system and converter stations. Had access to areas not many laypeople would ever see. I was very sad by the replacement of the rotary stations to solid state. I later became an engineer in broadcasting, baby sitting the big 50KW AM radio and TV stations in NYC/NJ. And as progress invaded my profession we too switched over to the solid state transmitters which did not require 24/7 baby sitting as did the all tube systems that was the mane stay of broadcasting for a long time.
here is the link to the PDF of the book that I was talking about. have a good read and look. it all links right back to the above video. www.nycsubway.org/wiki/The_Interborough_Power_Plant
One huge rotary converter resembles an early gear-less traction elevator machine. Bolt on the sheave, add the hoist cables. I once held a position as a maintenance engineer, at a hotel had two traction elevators, the controller was fairly recent (10-15 years earlier) still had the DC hoist machine and MG set. Which was a fraction of the size of this one. It was noisy. I believe later on MG was more the term with older elevators, and rotary converters "were known" as phase converters. Resembled an electric motor single phase in, modified 3 phase out.
When I was a young pup in the 70's I worked for a while in a foundry. I had to walk through the Power House to get to where I had to punch in. They had a couple of these things in the Power House. Never knew what they were or what they were for. The foundry used electric arc furnaces. I guess they were to fire those up. You know, it was dirty, smelly and dangerous working there but it was also damn interesting.
Il y avait une station près de la Bastille à Paris, l'été à cause de la chaleur ils ouvraient les parfois portes et on voyait ces belles machines tourner!
They need to spin it once in a while to oil the journal bearings and prevent rust, though it doesn't need to be spun at full rated speed for lubrication. Can also back off virtually all the brushes so they don't touch and wear down the commutator / slip rings, and use just two carbon blocks on two brush arms to spin it slowly.
until 1983 I had DC220v domestic supply so whenever I needed AC220v supply I had to depend on a Westinghouse DC to AC rotary converter ( 1 Kw). I still have the machine, not in use anymore because I have AC 220v domestic supply at home.
In close exam of the unit, it looks like it has a brake on the field so it can be induction started on AC instead of DC start. Would be needed for starting after a blackout as there needs to be initial DC to start the rest of the converters on DC to get them up to syncronous speed. Some of these early ones were 25 cycle machines, so not line started anymore after the conversion to 60 HZ. Does anyone know if the big hand wheel is a brake for the field, or is it to shift the DC brushes?
Not a fullBridgedRectifier but a "fullyRotatingRectifier"... amazing principles for high power rectification. (imagine how large "semiconductor diode rectifier blocks" - or "-arrays/networks" would have to be otherwise.
I've seen a motor generator run a dc motor for a large engine lathe, they look like huge torpedoes, also seen a few welders that were same setup, had to use what worked right☺
I’m an elevator mechanic. Still take care of many elevators that are run with motor-generator sets. Variable voltage control is the way to go for floor leveling accuracy.
Robert L Yup, basically an AC motor turning a DC generator. It would be a very inefficient way to convert AC to DC, but it was the only way to do it for a long time, before rectifiers were made that could handle a lot of power. They were very common on electric railway systems in the early 1900's.
Sounds like it has new brushes that haven't been bedded to fit the commutator segments, almost sounds like the brushes are catching on the segment edges.
I wonder what the Conversion efficiency is vs an solid state electronic system ? Not withstanding, building a solid state unit of that capacity would probably be cost prohibitive?
Research dynamo, this is just a honking big one with a three phase motor built in. It's hard to explain how it converts AC to DC without going all Vectory techo on you, yes the dynamo windings are making AC, but if you look carefully you will see the brush carriers are in groups marked + and -, by having those groups in the correct location around the housing it's possible to grab the positive half cycle for the + brush and the negative half cycle for the - brush. Those old engineers were very very smart fellas.
This is how AC was converted to DC before vacuum tubes or semiconductor diodes existed. Each brush arm is an opposite DC polarity, and each wound pole piece is flipped N-S-N-S. This allows higher DC amperage by adding the brush arms together in parallel.
Is this rotary converter running on a regular basis, as a backup or just being kept for historical/educational reasons ? Thanks for posting this. Not many around :)
It doesn't run anymore. It is kept for historical and educational reasons. I have more pictures and information on my blog post. www.geekygirlengineer.com/2017/04/16/mta-substation-13/
Hello, I have often seen 3-phase AC to DC rotary converters (either Leonard or Ilgner type) in old mines and in rolling mills. However this one looks quite different as there is only a single engine, which must be a combined AC motor - DC generator? Do you know if the motor is a synchronous type? (The distributing rings seem to point into this direction.)
Harald; Yes, you are correct on both points: 1: This is a combined machine in which the "motor" and "generator" are combined and share both the magnetic pathways in the rotor and stator and the copper pathways in the rotor. This makes for a much smaller and more efficient machine than a separate motor and generator. The basic reason the machine can be smaller (for a given power rating) is that the currents and magnetic flux created by the DC currents and the AC currents tend to be in opposite directions so they partially cancel out so you can use smaller wire winding and smaller magnetic cores than in a separate motor and generator capable of converting the same amount of power. 2: Yes, it is synchronous type originally fed with 25 Hz. AC. See the 2 minute point in this video: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-Maxf1C68wdo.html which is a quite a bit more technical presentation of the same converter. I hope this helps... Vince
@@gregwarner3753 ok that makes sense, the biggest diodes I could find on amazon were 100 amps @1600 volts which is probably overestimated, even by putting them together they would probably just become silicon heating elements
@@clarencegreen3071 LOL its just a 2 foot square generator i wheel it on the porch when we lose power haha its amazing how big that is for only 1500 kw lol
9000 kilowatt generator? Are you sure it isn't 9000 watt/9 kilowatt? A 9000 kilowatt/ 9 megawatt generator is going to be much bigger than 2 feet square.
