Wednesday, September 6, 2023

Electrical Mystery

Here's another diagram from the Brookins Collection of CA&E blueprints and wiring diagrams.

Question: What's wrong with this picture?


When I first saw this, I thought "Of course the CA&E never had any North Shore steel trailers, they just meant WB&A!"  But the WB&A cars had GE M control with C-80A controllers, not Westinghouse.  Evidently someone had the bright idea (probably in the late 30's) of acquiring spare North Shore steel trailers and cobbling up control jumpers that would enable them to MU with the CA&E steel cars.  This would require running the Westinghouse controllers on straight 600V, and how well that would work is anybody's guess.  They're certainly not designed to be used that way.  So I'm pretty sure this bizarre plan never went anywhere.  And I can guarantee we're not going to try anything so hare-brained here at IRM.  Let's see, that leaves two other possibilities elsewhere....  :) 

6 comments:

sd45elect2000 said...

I think the motorman would be wearing high voltage gauntlets to operate the controller ..

Randy

Scott Greig said...

Yeah, good point, the type M control circuit would have been at 600 volts while the Westinghouse line voltage control circuit was only designed for about 150....

I wonder if this was a sort of lead-up proposal that led to them ultimately leasing both trailers and low-700 motor cars from the North Shore in the 1930s.

Randall Hicks said...

Since the diagram isn't dated, it's hard to say. Besides the WB&A cars they also acquired the twelve North Shore wood cars on a permanent basis.

Anonymous said...

You know what they say about opinions, but I'll offer mine here. I think that while it's an unusual arrangement, I can't see anything inherently wrong with it. Remember that NSL 28A controllers have live 600 inside them, as well as divided line through the control resistance. (The control resistance isn't live all the time. Guess what switches the trolley on and off to it!) If you have a control resistor open up, particularly the section from 7 to G, the car may continue running if it isn't being used in MU. Voltages go all over the place and operation may be unreliable or erratic, and you may get overheated coils, but something that *doesn't* generally happen is pyrotechnics inside the controller. In fact, I'll posit that the worst part of this proposal is having both ground and trolley on the shaft segments, right next to each other. But hey, it's supposed to be insulated for 600v anyway. They might have needed to add some transite boards in between the upper and lower sets of fingers, perhaps.

As for needing high voltage gloves- I don't think we're the only place that has motormen operating K controllers with their sweaty paws in the summer, and nobody bats an eye.

R. W. Schauer

Randall Hicks said...

Richard: What you say is true, but in order to run GE control systems you would need to remove (short across) the control resistance that feeds the controller on a Westinghouse car. And the arcing that occurs inside the controller is a function of both the applied voltage and the current being broken. So I wouldn't be surprised if a Westinghouse controller flashed over badly once you had done that. Let's not try it.

Also, I'm pretty sure Randy was joking about the insulated gloves. K controllers, such as the ones about to be installed on the 306, all run on 600V and carry much higher currents than any MU system, but they're designed for it. That's why they all weigh two or three tons.

sd45elect2000 said...

Yes, I was half joking because the K style controller has arc suppression, blowout coils, magnets and whatnot to suppress the arc. In addition most of the K style controllers have a wooden cover, MU controllers do not.
Like Randy said, I don’t want to try it. Even though MU controllers are perhaps insulated for 600 VDC I’m not staking my life on it .

Randy