Electric generation in the USA

[ppppenguin]

This site gives details of a wonderful old hydo power plant that is still in use. It may be open as a museum.
http://edisontechcenter.org/Mechanicville.html

[pwdrive]

Thanks for the link Jeffery, a nice bunch of old generators....watch yer body bits......!

[Kalee20]

Super! Wondering what consumers use the 40Hz though?

[ppppenguin]

None use 40Hz these days but historically there were many frequencies used.
https://en.wikipedia.org/wiki/Utility_frequency

[Radio Fixer]

No mention of Tesla !

Gary

[ppppenguin]

Tesla invented the 3 phase power system that is almost universally used. This was by far his most important idea. For better or worse he is usually remembered for the drama of the Tesla Coil and some of his more controversial work.

Edison used the lowest frequency of all: 0Hz or DC. Inevitably lost out to AC as power stations became bigger and transmission distances longer. If you were starting again now you might well use DC. Modern electronics makes transforming DC voltages relatively easy and much equipment would be fine with a DC supply. One annoyance would be switches. It's much easier to switch AC as the arc extinguishes at each zero crossing.

[Terry]

 Modern electronics makes transforming DC voltages relatively easy and much equipment would be fine with a DC supply. One annoyance would be switches. It's much easier to switch AC as the arc extinguishes at each zero crossing.

Hence the once universally popular toggle switch with its spring assisted quick make and break contacts.

I doubt if today's slow switches would last very long - they aren't much better than the simple switches I made as a schoolboy with a construction set and brass strips salvaged from an Ever Ready 1289 4½V battery.

If you're not familiar with the 1289, here's a modern version - note the long and short brass terminal strips.

[Ed_Dinning]

Hi Gents, John Henry Holmes, a Newcastle Electrical Engineer and inventor of the quick break switch.
Mainly from the days of DC and "key type" switches, where it was possible to partly open the switch, leaving it arcing and dimming the lamp. Very much like the gas lighting. BUT not a good thing as the switches were often on wooden bases!!!

Discovery museum in Newcastle has an exhibition of his designs.

Ed

[ppppenguin]

The DC isolator on my solar PV system looks like 3 (maybe 4) ordinary AC switches in series on a common shaft. Switching off HVDC (100kV+) must be quite tricky.

[Terry]

ABB (Air Blast Breaker), perhaps, as used on electric trains @ 25kV?

I'm not sure of the precise way it works but consists of a blast of high pressure air between the contacts to extinguish the arc.

I wonder if it actually blows the arc sideways so that it forms a sort of 'U' shape, thus extending the length of the arc very rapidly so that it extinguishes in a much shorter time?