[PRCo] Re: More Thoughts on 1600s versus 1700s

[Jim Holland]

Good Morning!

> Fred Schneider wrote:

> The cars with blown motors probably could be made 
> peppier than those with internally vented motors,
> because the external fan on the MG set could keep the
> motors cooler at lower speeds.  But I have never seen
> any proof that specs for the limit relays were changed
> on cars with blown motors.  Now I know I'm speaking
> Greek, right?  The motors on the original PCCs
> (and on most streetcars before them) were cooled by
> a fan on the armature in the motor.  Of course the fan
> runs fastest when the motor run's fastest. 
> And the greatest heat is generated when the motor is
> revolving very slowly.  Fineview was very abusive to
> such a car.

> Blown is synonymous with extenerally vented -- those
> cars with blown motors required a separate fan on the
> MG set just to cool motors.  The distinction was
> generally air-cars were internally vented and
> all-electrics had externally vented motors.

	Cheese__Whiz, Fred    ----    how about giving us the definitions up
front?!?!(:->)     From your discussion, I had the  *Vision*  that a 
*Blown__Motor*  was one that shorted out  In-Service,  was thus
shopped and rewound, and the materials used in the re-winding allowed
for a Peppier Car.    I had not a little difficulty(!) understanding
the association with venting!    This is your Sunday Afternoon Humor,
Yes?!?!(:->)

	Anyhow, isn't  *Externally--Ventilated*  *Generally*  associated
with  1.)--the longer trolley cowl on the Air-Cars?    2.)--.......And
also the lack of the air intakes centered above the trucks on each
side of the car?

	Cars 100 and 1000--1199 had #2, while 1200--1699  (Minus 1565--1699
and 1600) had #1.

	So all the cars from 1200 forward did Not have Armature Mounted Fans
but Did have motors cooled via Fan(s) in the MG set which ran
continually.    Cars 100 and 1000--1199 had armature mounted fans
which would spin at the identical speed of the motor!

	Thus, cars 1200 and forward would be peppier than 100 and 1000--1199
except for the weight factor!

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James B. Holland

Holland  Electric  Railway  Operation....... 
___"O"--Scale St.-Petersburg Trams Company Trolleycars and...
______"O"--Scale  Parts  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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