[PRCo] Re: Cin

[Fred Schneider]

No one has questioned it yet but before they do:  I would assume that  
the middle wire is the positive wire and the two outside wires are  
negative grounds but it doesn't matter.   Unlike model railroad  
motors with permanent magnets for a field, the trolley cars and  
trolley buses used series wound motors.   If you reversed the  
polarity of the field, you also reversed the polarity of the armature  
simultaneously and the car continued to run in the same direction.    
So reversing which wire was positive and which was negative had  
absolutely no affect.

With the undergound conduit systems in Washington and New York, if  
the hot conduit developed a short, and that happened from time to  
time, it was a simple matter just to reverse the polarity and make  
the ground conductor hot until they could find time to locate and fix  
the problem.   The cars didn't know the difference.

To reverse the car you have to change the direction of the motor  
field connections versus those of the motor armature connections and  
that reversal is done on the car.   The old Lionel toy locomotives  
also had series wound motors ... remember the little reverse switch  
that came out the top of the boiler?

On Jan 15, 2007, at 11:00 AM, Bill Robb wrote:

> Here's a couple interesting shots of Cincinnati:::::::
> .
> 1166 appears to be on a short stretch of single track  --  ON  prw  ON
> the Sidewalk(!!!)  --  with 3-wire overhead, one wire shared in common
> in both directions.       Note the overhead in the distance how it
> separates into w sets of double overhead and it is doing the same  
> above
> the front end of the car.
> .
> The second photo with 1165 confirms that there is a second track at  
> this
> location again with triple overhead, a set of which turns left across
> the overhead that goes over the sidewalk!       Would like to know  
> more
> about the track layout here and if this is really near the Zoo for  
> which
> there may be several layover tracks!!
> .
> .
>  http://lists.dementia.org/files/pittsburgh-railways/1166%20X%20Zoo% 
> 201950xxxx.jpg
>
> http://lists.dementia.org/files/pittsburgh-railways/1165%20Lockland% 
> 20&%20follower%201950xxxx.jpg
>
> Here's a photo of the Zoo loop:
>
> http://homepage.mac.com/jjakucyk/Transit1/loops/pages/page_4.html
>
> Cincinnati streetcar info:
>
> http://homepage.mac.com/jjakucyk/Transit1/index.html#csr
>
> Cincinnati Transit Historical Assn.
>
> http://www.ctha.org/index.shtml
>
>
>
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