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VK3ABK > INFO 05.07.02 21:00l 30 Lines 1145 Bytes #999 (0) @ WW
BID : 28749_VK3VSW
Read: DB0FHN GUEST
Subj: RE: KB2VXA AND SPEED
Path: DB0FHN<DB0ZWI<DB0MAB<DB0FBG<DB0CHZ<OK0PKL<OK0PPL<RZ6HXA<SP7MGD<ON0BEL<
VK3TE<VK3SPB<VK3FRC<VK3VSW
Sent: 020703/1344Z @:VK3VSW.#WEV.VIC.AUS.OC #:28749 [Geelong] $:28749_VK3VSW
From: VK3ABK@VK3VSW.#WEV.VIC.AUS.OC
To : INFO@WW
Hello Warren and other voltages.
You ask about alternator and motor rotation speed and wonder why.
I Australia we have 50 Hz AC supply and one way to get this, but not
the way it's done, is to run a 2 pole alternator at 3000 RPM.
This gives 3000 divide by 60 = 50 Hz AC output.
Alternatively, so to speak, a 4 pole alternator running at 1500 RPM
would give the same 50 Hz AC output. But an induction motor connected
to a 50 Hz supply would run at about 2800 RPM for a 2 pole machine, or
about 1440 RPM for a 4 pole. The difference between synchronous speed,
ie. the alternator speed, is due to 'slip' which is the out of sync
due to magnetic reluctance. These motor speeds are for rated load, and
the motor will run faster on light load and approach synchronous speed.
The American 60Hz would mean higher speed for both alternator and motor
ie. 3600 RPM and 1800 RPM alternator speed, and about 3100 RPM and 1550
RPM for the motors.
As you say, Warren, this has been a amazingly interesting topic and
I would add, a magician could not beat a technician at this game.
73. Dick. VK3ABK.
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