3 Phase electricity



There is a nice and interresting book "The man who invented the 20th century" about Nicolay Tesla (Camden Books has it in their list). The AC/DC (no notes intended) battle was between Tesla and Eddison. Eddison trying to proove the superority of DC and the dangers of AC. Eddison made promotion tours and electrucuted dogs (that local boys caught for a penny) with AC. The electric chair must have been working with AC.
Nick
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Power
hacked
system
chair,
the
By one of those co-incidences there was a programme on one of the History Channel type thingies last night about the battle between Edison (advocating DC) and Westinghouse & Tesla (advocating AC) Apparently Edison was asked to quote for the electric chair, but he advised the authorities that the Westinghouse Generator was more appropriate and that the process of electricution should be called 'being Westinghoused' . Obviously this was a nasty marketing spin approach. In the event the first chap for the chop had 1000v applied several times but survived, so the doctors advised high volts and eventually bumped him off with 2KV.
AWEM
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streets,
Around here the street lights are run from the same phase as the houses on that side of the street, they take relatively little power so there's no need for a separate feed for them.
Greg
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The 1958 edition of Newnes' Electrical Engineer's Reference lists the voltages and types of power supplies for fairly small towns and upwards. It looks as though about 20% of those listed still had some DC supplies. I only spotted one that had DC only - Lytham St. Annes - but there are probably a few more. Luton is listed as having some 250/500 DC as well as 240/415 AC
At school, in Cheltenham in the early '50s, the machines in the engineering workshop were driven from line shafting powered by a large DC motor. It was started with a rotary switch which had a ring of large brass studs switching resistors in the armature circuit - all fully exposed!
Bob
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I believe that the Luton power situation by then was mainly AC but there were some industrial locations still on DC, certainly I think all domestic stuff was AC by then. Kent Meters and Vauxhall were possibly still taking DC as they were both relatively local to the power station.
Interesting what turns up in the way of information! :-))
-- Peter & Rita Forbes Email: snipped-for-privacy@easynet.co.uk Web: http://www.oldengine.org/members/diesel
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As I said, situations vary. The situation in very high density areas like London in particular is often different. Around here the system I described is the norm, whether it be a 50's estate or one built in this century, of course the earthing practices are different between the two.
Possibly my choice of the phrase "main road" was a bit misleading, for example if we have an estate with half a dozen parallel roads each is on one phase, and the road joining their ends has all three phases with a junction box at each T junction.
Greg
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