(Side note) - Great site for introductory AC motor (rewinding) basics:
So, if a three phase, 4 pole (1800rpm) motor has 12 pole-phase groups
(PPG's), can these PPG's be reconnected for a single phase, 12 pole
(600rpm) motor? (Of course it would not be able to self start, not an
issue if, for instance, you are creating a low rpm generator)
Here is what I did as an expirement:
I took a 10hp, 3 phase, 200V (3 lead) Baldor motor (equivelent to
current cat. # M3313T-8), found the internal star connection and broke
it apart. Then connected three leads and routed these leads to the
outside with the other 3 leads. The 3 original leads are the starts
(S) for windings 1 through 3 and the 3 new leads are the finishes (F)
for the same 3 windings. I then connected the 3 windings in series,
1F to 2S, 2F to 3S. I gave the motor a gentle spin and connected 1S
and 3F to 120VAC. It runs 600 rpm.
The specs for this motor state that it should run 20A on 200VAC 3ph,
Having only 240VAC 3ph, I connected it (factory configuration) and
measured 33 amps per leg, no load.
Reconfigured for 12 pole, single phase, it runs 33 amps on 120VAC.
(This is a 2 times the square root of 3, or 3.464, reduction in input
I connected a buck transformer to reduce the input voltage to 102VAC,
it runs 26A, no load.
I have not been able to evaluate torque performance (although it will
shread a glove in short order if I grab the output shaft), nor have I
been able to evaluate performance as a generator. I did confirmed
the 600 rpm with a strobe.
Any comments or recommendations?
18 years ago