TELECOM Digest OnLine - Sorted: Re: 25 Hz power

Re: 25 Hz power
Thu, 9 Mar 2006 16:43:11 EST

In a message dated Wed, 8 Mar 2006 12:45:38 CST, jsw
<> writes:

> In NYC up into the 70's at least, power for two of the subway
> divisions (BMT and IRT) was generated at 25Hz but converted to DC in
> the field.

Some electrified intercity railroads in the Northeast used 25 Hz
power. There are, or at least were in the past, some advantages to 25
Hz power for running locomotives. (Some railroads in other parts of
the world use or used 16-2/3 HZ power.

> However, I very distinctly remember the flicker of the
> incandescent lamps in some of the BMT stations in the 60's, as these
> were operated from the unrectified 25Hz source. I do remember that
> some people claimed they could not see this flicker, but it was very
> obvious, to me, anyway.

This same flicker was apparent when I stayed with my parents at the
Fred Harvey Hotel at the Santa Fe Railroad station in Gallup, New
Mexico, in the late 1940s. It was my assumption this was built before
there was a public electric power system in Gallup and that the hotel
was supplied by the Santa Fe's own power plant, built probably well
before the standardization of 60 Hz power in the U.S.A.

In a message dated 8 Mar 2006 13:09:09 -0800,

> Note that for many years DC power was provided by commercial
> utilities. Originally, Edison's power plants supplied DC. There was
> a big fight between Edison and Westinghouse over DC vs AC. AC won
> out.

Most of today's power companies descended from Edison's companies and
are still reluctant to give any credit to Nikola Tesla, who conceived
of the far more practical (for most commercial purposes) multiphase
alternating current now universally used. (Westinghouse bought the
Tesla patents.)

Wes Leatherock

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