[PRCo] Re: PCC__Speeds

[Jim Holland]

Good Morning!


> boris6 at volny.cz wrote:

> When you look at 1700s Westinghouse schematic diagram,
> will see that these are suitable for change from
> 50% to 67% field shunting, so they were possibly
> capable of faster acceleration after the accelerator
> resistance was short-circuited by M2 contactor.
> Of course, the "overspeed relay" (this term is used in
> diagram) somes into play when car speed reaches the
> adjusted value of that relay.    But don't know,
> if that 67% shunting was used.

> Boris


	A couple of questions, please::

1.>--	You say that changing from 50% to 67% field-shunting yields
faster  *acceleration.*    This would just be the 
*Rate--of--Change*  in speed, not the ultimate speed  --  is this
correct??


2.>--	Would this change in field-shunting affect spotting
circuitry when the power pedal is released?    If yes, would it
explain why the PRCo  1775--1799  cars had quited a strong
dynamic drag when the power was released?


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Waiting for a bus is as thrilling as fishing,
    with the similar tantalisation that something,
        sometime, somehow, will turn up. 
            George Courtauld

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James B. Holland

• Holland  Electric  Railway  Operation....... 
  "O"--Scale St.-Petersburg Trams Company (SPTC)
	Trolleycars and "O"--Scale  Parts
		including Q-Car
	mailto:pghpcc at pacbell.net

• Pennsylvania Trolley Museum
	http://www.pa-trolley.org/
• Pittsburgh  Railways  Company  (PRCo),
	1930  --  1950
• N.M.R.A.  Life member #2190;
	http://www.nmra.org

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