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SINGLE PHASE MOTOR STARTING CONVERSION

SINGLE PHASE MOTOR STARTING CONVERSION

SINGLE PHASE MOTOR STARTING CONVERSION

(OP)
HI, I have to rewind the start winding of a 1/4 HP 4 poles 120 VAC motor. The original start windings were 56 turns of 22 gage wire for each pole.

I wish to modifiy this motor to add a starting capacitor to improve starting torque. Does anyone knows what size of capacitor would be required and if I need to modify the start winding (more turns?, wire size?)?

Thanks

Dany

RE: SINGLE PHASE MOTOR STARTING CONVERSION

Suggestion: Visit
http://www.tpub.com/ceb/108.htm
http://www.twysted-pair.com/wwwboard/messages/491.html
http://www.franklin-electric.com/empd/tech/fe-basic.html
etc. for more info. Only this type of motor designer can give you correct answer since it is very specific. Generally, the capacitor size varies and it can be from 100microfarads to 200microfarads. The wire gage should be able to carry more than 5.8A. Check
http://www.ibiblio.org/obp/electricCircuits/Ref/REF_3.html
http://www.fse-power.com/
for wire ampacity info. It appears that 22AWG may be so-so.

RE: SINGLE PHASE MOTOR STARTING CONVERSION

(OP)
Tanks for the info,
I talked last week with the local electrical motor repair shop and they said that for a 1/4 hp motor, a 160 uF would be ok.

I installed one an it worked fine. I will never know if I get the higher starting torque possible but it seems ok.

There's certainly a way to find out what cap size would be the best but I could find it on the web.

By the way, I have two 3/4 hp, 110-220 vac motors, they both use a 378-455 uF cap. (May be it can help someone else...)

Dany

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