Re: Q about multi-phase motors.

["Tim Nichols" <tnichols@voicenet.com>]

The reason why 3 phase is so popular, and we don't have 4, 5, or 6 phase, is
that if you look at a graph of all three wave forms, you will see the power
is conintuous.  When one wave form is at zero, the other two are at nonzero
states.  Thus, there is no instant when a 3 phase system doesn't have the
same power level.  Not true of single or dual phase.

Tim Nichols
tnichols@voicenet.com
'87 Electric Escort (Hope to be done by April)

See my web page at:
http://www.voicenet.com/~tnichols
-----Original Message-----
From: Stephen Barnes <steve@spbarnes.demon.co.uk>
To: ev@listproc.sjsu.edu <ev@listproc.sjsu.edu>
Date: Sunday, February 28, 1999 9:15 AM
Subject: Re: Q about multi-phase motors.


>Peter VanDerWal wrote:
>>
>> >Why only up to three-phase motors?
>>
>> I think one of the reasons folks on the list are interested in
three-phase
>> motors is because inexpensive three-phase industrial motors are available
>> 'off the shelf'.
>>
>> If you went to 5 or 7 phases, then you'd have to have a custom made
motor.
>
>Or 4 or 6 phases for that matter.
>
>The only reason I can think of apart from having to get a custom made
>motor is the cost of the extra IGBT's you would require.
>
>Steve
>
>