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Joined: Aug 2001
Posts: 7,520
pauluk Offline OP
I've just acquired a book published in 1959 which states that some West Coast areas use 50Hz supplies and that parts of upstate New York have 25Hz power.

Now I know from discussions here in the past that the Los Angeles area once had 50Hz power but switched to 60Hz in the 1930s, but just how many other areas used something other than 60Hz?

And were 50 and even 25-Hz systems really still in use as recently as the late fifties?

Joined: Oct 2003
Posts: 156
Paul, not for certain, but I do not think it is possible for anything other than 60. Reason being is the interconnected grids throughout the country.

Joined: Mar 2003
Posts: 97
I wired up a factory that made equipment for export.

Had two 50 hz generators. They were actually 60 hz electric motors belt driving 50 hz generators.

Also had single pole double throw type switches so they could switch between power sources at the same test station. Each test station was 400 amp using camlocks.

I recall no differences in wiring size or wiring methods or anything like that.

Not a whole lot of information here, I just wanted to make you aware that 50 hz is used in house for testing purposes.

Joined: Sep 2001
Posts: 806
And lots of facilities that work with aircraft or military electronics have 400 Hz power available, usually via a motor-generator set.

Joined: Jun 2004
Posts: 202
Pensylvania Railroad used 11000VAC @ 25Hz for electric traction with the GG-1 electric locomotives. Don't know if this is still the case today

Joined: Jan 2005
Posts: 354
pdh Offline
Some West Virginia coal mines used power around 25 Hz as late as 1952 when my grandfather was a mine electrician. He later described his work to me. Some of the small towns next to the mines were powered the same. He said the flicker in the incandescent lights was visible.

Joined: Mar 2005
Posts: 1
Junior Member
There are Two main HIGH voltage distribution systems in the USA. Direct Current and 60 HZ.
As was mentioned by dereckbc, the USA is on two Grid systems, East and West, and MUST be 60 HZ. If a given generation plant starts to deveate from the 60 HZ, the others pull it back. Individual Facilities may have converters to different frequancies for their operation, but the UTILIT grid is always 60 HZ. Outside the USA, I have found only 50 and 60 HZ from Utilities, with some countries having both.

Joined: Aug 2001
Posts: 7,520
pauluk Offline OP
Grids having to be synchronized is a good point, but could it be that back in the 1950s there were still some small areas which were not connected into statewide and national grids but just had a few power stations running a local network?

In England at this time, there were some cities in which the older, downtown districts were still running on their original DC distribution systems fed from a local power plant, even though outer, newer areas had been interconnected to the grid to get AC power.

Some West Virginia coal mines used power around 25 Hz as late as 1952 when my grandfather was a mine electrician.
That sounds very much like a local power plant along the lines I'm thinking about. Didn't many of the small mining places in WV start out as company towns? It seems quite probable in such a case that the mining company might have installed local generators to their own standards for the whole town.

Pensylvania Railroad used 11000VAC @ 25Hz for electric traction
25Hz was also used on some railroad lines in Britain in the past. The 25kV AC power supplied for all the main electrified lines these days is 50Hz though, with substations providing power from the main national grid.

Joined: Nov 2002
Posts: 456
AFAIK, there are more separate grids.

I know for a fact the Quebec and Southern Ontario grids are separate, and I heard Texas is practically on their own grid.

On the whole, I think the separte grids may be:
Quebec/eastern Canada.
South Ontario/Northeast US
South East US
Midwest US
Western Canada
Western Seaboard (including BC).
Alaska is probably a whole separate grid, and of course Hawaii will be too.

Joined: Jan 2005
Posts: 4
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