[PRCo] Re: voltage and frequency

[Boris Cefer]

Probably both types. I am not familiar with details with AC operation.

Why would the light flicker? Today everything is fed from a battery which is 
charged through a converter.

Yes, for AC variable transformers are used, there are no loses in 
resistances. AC can't be thyristor controlled.

B

----- Original Message ----- 
From: "robert simpson" <bobs at pacbell.net>
To: <pittsburgh-railways at dementia.org>
Sent: Friday, August 31, 2007 12:43 AM
Subject: [PRCo] Re: voltage and frequency


> Good information - thanks for sending.
>
>  A couple questions....
>
>  Are the motors on European trains A.C. or D.C.?    and...  why doesn't 
> the low frequency (16.6 Hz) make the lights appear to "flicker"?   Having 
> ridden many trains in Eurupe, I heve never noticed any flickering.  How is 
> this prevented?   I once was told that the European trains used D.C. 
> motors and SCR's for control.  For A.C., the only way I can think of to 
> control speed would be motors with multiple windings or variable 
> transformers.
>
>  I heard my father once mention that he was visiting Niagara Falls long 
> ago (possibly 1920's?) and they had 25 Hz which made incandescent lights 
> very annoying.
>
>  Bob Simpson
>  from Krazy California