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Tim Wescott
 
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Default Need help wiring single phase motor


"Patrick C." wrote in message
om...
"Tim Wescott" wrote in message

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"Patrick C." wrote in message
om...
I picked up a single phase motor at a surplus shop and can't get it to
work correctly. It's a Bodine 120v, 1/3 hp gear motor, and does not
have the start or run capacitors included. The model number isn't
listed on Bodine's site so I'm guessing it's an old one or a special
application model. It has four leads- white, red, blue, and ground.
The brief 'instructions' from the surplus shop say to wire it "White
to AC, Blue to Capacitor, Red to AC and Capacitor", but when I did
this it only turned about 1/6 the listed speed. Can anyone tell what
I'm doing wrong? Should the AC and motor leads go to the opposite
sides of the capacitor? Thanks for any help.


Induction motors like to run just a bit slower than the synchronous

speed.
If it's starting at all and it isn't making loud buzzing noises, drawing
excessive current, getting hot or letting forth smoke then the motor is
hooked up correctly. Is the ID plate on the motor or the gearbox?

Maybe
someone replaced the original motor, and the listed speed is for another
gearbox, or no gearbox? If the listed speed is 3600, 1800 or even 1200

RPM
then chances are that's the motor shaft speed, not the output shaft

speed.

Sorry, should have included this the first time- It is getting hot and
shutting off (lucky for me it has thermal protection). The nameplate
speed is 180 rpm, and it's only turning about 30. It will start
without the capacitor, which suprised me, but something's still not
right.


If Bob Englehardt's answer doesn't make you smack your forhead and scream,
ask yourself if the thing may have come off of an aircraft or boat?
Aircraft use 400Hz power, using 60Hz instead would make a motor turn at
33RPM instead of 180, and would make it get quite hot. I'm really reaching
here, so let about 10 more unhelpful posts show up before you start taking
it seriously.

I don't have a good explaination for why it should run at all without the
capacitor -- usually a single-phase motor like that is either running or
getting _very_ hot.