Stray voltage on 220-3ph when breaker is off

[gar]

130715-1722 EDT

Stopped at Greenfield Village today. The nominal voltage setting for a Detroit power plant, about 1885, was 110 V. Approximate coverage range was a radius of 1 mile.

From one 150 HP steam engine there were two generators, each 30 or 40 kW. Full scale on the voltmeter was 150 V. An adjustable resistor was used for field control.

The Menlo Park generators are more in the 5 kW range and are 1879 vs mid 1880s. There were no voltmeters in 1879. Weston made great strides in a few years.

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[meternerd]

I guess there's no point in explaining high impedance meters and "phantom voltages."

 

[gar]

130715-2123 EDT

It seems the original poster was a DIYer, therefore the subject drifted to that discussion.

I also think that there may be some electricians that don't know how to solve his problem, and that may or may not be the source of his problem.

Personally I don't know whether or not he should have been given help. I think some questions brought up by DIYers deserve discussion because of the possible teaching experience. But possibly this means a discussion without direct help if that is even possible.

The following is more off subject.

Francis Jehl, I believe, references a compound field for voltage regulation. I don't see evidence of this in the 1879 generators. Now I will search his book a little.

About 1877 the ohm was defined as the resistance of #9 iron telegraph wire 396 feet long. Resistance was the most accurate measurement that could be made at that time.

More later.

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