TELECOM Digest OnLine - Sorted: Re: Buffalo NY 25 hz Power

Re: Buffalo NY 25 hz Power
8 Mar 2006 13:09:09 -0800

DLR wrote:

>> In 1957 and 1958, after graduating from Kenmore High School, near
>> Buffalo, I was a turbine operator at Niagara Mohawk's Charles R. Huntley
>> Steam station in Tonawanda, on the Niagara River. We were still
>> operating units 25 hz 24, 25 and 26 and a reversable frequency changer.

> Who bought this 25Hz power?

In the 1920s and 1930s certain AC motors had to be 25Hz. I don't know
why. But major railroad electrifications like the Pennsylvania,
Reading Co., and New Haven used 25 Hz (11,000V). (Former PRR/RDG
routes still do to this day.) The electric motors of prewar trains
used the 25 Hz. Also, streetcar systems used 600VDC and used rotary
converters (an integrated motor-generator set) to convert the power;
these also ran off of 25Hz. Modern trains either rectify the AC power
to DC or convert it around to AC control.

So, it was common for commercial power plants to supply 25 Hz and
continue to supply it for legacy customers. I don't know who supplies
today's Amtrak's 25 Hz--whether the power company provides it that way
or it has to be converted by the carriers. SEPTA converts theirs,
having finally replaced old worn out rotary converters with solid state

In the Buffalo area there was an electrified freight switching railway
known as Niagara Jct. That probably consumed the 25 Hz. There may
have been industrial customers as well.

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

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