The single phase you are feeding to the motor has 2 sine waves 180
degrees out of phase with each other. Three phase is supposed to have three
sine waves 120 degrees out of phase with each other. If you are generating a
third phase , there is no place in the 360 degree cycle to squeeze in
another sine wave. You are going to end up with some really dirty power.
The lathe may be able to deal with the dirty power, but you are creating
a problem for the rest of the circuits in the home, the utility, and your
neighbors. This situation is likely to create problems with phase shift,
cycle instability, transients, overloaded neutral conductors, and
overheating.
If the utility finds the source of their problems, they are likely to
pull your meter to protect themselves, and their customers.
Jim Smith, KQ6UV
----- Original Message -----
From: "jeff millar" <jeff@wa1hco.mv.com>
To: "Peter Chadwick" <Peter_Chadwick@mitel.com>; <amps@contesting.com>;
"'William Fuqua'" <Wlfuqu00@pop.uky.edu>
Sent: Thursday, April 19, 2001 6:02 PM
Subject: Re: [AMPS] 3 phase transforers and single phase
>
> I have an old metal lathe with a three phase motor. In order to get three
> phase power to drive the motor I got a 5 HP three phase motor from the
junk
> yard. I connected 240 across two of the phases and it generates the third
> phase just because it's spinning. It doesn't want to start by itself, it
> just sits there humming and smelling very hot. To start it, I just turn
on
> the power and give the shaft a flip with my foot and it takes off. If you
> need more power, just connect multiple motors in parallel. When I start
or
> reverse the lathe, the motor on the floor hums louder and jumps around a
> bit...very cool..
>
> The voltage generated by the third phase runs a bit less than the the
other
> two. Probably not a problem in practice. This trick should work very well
> to generate three phase power for transformers and rectifier systems.
>
> jeff, wa1hco
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