need help with start capacitor

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howdy!  im working on a electric motor for a dust collection for wood working im building.   the motor won't start, just hums when switched on.  i have taken the motor end off that has the capacitor centrifugal start switch and am going to replace the centrifugal switch along with the contact point plate just because its apart.  i ohmed both the windings and the windings ohmed correctly.the motor is a 120 volt capacitor start. the capacitor is 200 mfd 120v.  i got a good volt-ohm meter, just doesn't do the capacitor test.  took cap. to town and checked with my mechanics snap-on meter.  it tested at 245 mfd. im assuming that at 243 the cap. reading is bad.  the only place i could find the exact replacement is on eBay and this is the one:https://www.ebay.com/itm/193665019370?delivery date is about 4-6 weeks which really isn't a concern but if i could find a replacement sooner i could do that also.   just also wondering is there a hard start cap. that i could use also?  what makes a hard start one different from a regular start capacitor?thanks   robp.s. will also take other end of motor off and check armature and commutator next week when cooler!lincoln 125spdayton 250 ac/dcmiller 211 w/spool gunahp  200 sx tiglotos ltp5000dkubota b3200 FEL BHof course duramax diesel
Reply:The capacitor test size is not cheapI use a spare capacitor and see if that is the problem. Dave

Originally Posted by duramax-rob

howdy!  im working on a electric motor for a dust collection for wood working im building.   the motor won't start, just hums when switched on.  i have taken the motor end off that has the capacitor centrifugal start switch and am going to replace the centrifugal switch along with the contact point plate just because its apart.  i ohmed both the windings and the windings ohmed correctly.the motor is a 120 volt capacitor start. the capacitor is 200 mfd 120v.  i got a good volt-ohm meter, just doesn't do the capacitor test.  took cap. to town and checked with my mechanics snap-on meter.  it tested at 245 mfd. im assuming that at 243 the cap. reading is bad.  the only place i could find the exact replacement is on eBay and this is the one:https://www.ebay.com/itm/193665019370?delivery date is about 4-6 weeks which really isn't a concern but if i could find a replacement sooner i could do that also.   just also wondering is there a hard start cap. that i could use also?  what makes a hard start one different from a regular start capacitor?thanks   robp.s. will also take other end of motor off and check armature and commutator next week when cooler!
Reply:Is the top of the used cap blown? They have a paper seal over the "blow hole" is it oily or is there tar over it? Did you check the input voltage? As long as the microfarrads and voltage are correct the caps are the same, different terminals doesnt matter. so any 120 volt 200 mfd start cap will work. google is your friend. Good luckhere is one for 3 buckshttps://www.supplyhouse.com/MARS-110...citor-110-125VLast edited by WILLYSOVERLAND; 13 Hours Ago at 02:41 PM.
Reply:

Originally Posted by duramax-rob

howdy!  im working on a electric motor for a dust collection for wood working im building.   the motor won't start, just hums when switched on.  i have taken the motor end off that has the capacitor centrifugal start switch and am going to replace the centrifugal switch along with the contact point plate just because its apart.  i ohmed both the windings and the windings ohmed correctly.the motor is a 120 volt capacitor start. the capacitor is 200 mfd 120v.  i got a good volt-ohm meter, just doesn't do the capacitor test.  took cap. to town and checked with my mechanics snap-on meter.  it tested at 245 mfd. im assuming that at 243 the cap. reading is bad.  the only place i could find the exact replacement is on eBay and this is the one:https://www.ebay.com/itm/193665019370?delivery date is about 4-6 weeks which really isn't a concern but if i could find a replacement sooner i could do that also.   just also wondering is there a hard start cap. that i could use also?  what makes a hard start one different from a regular start capacitor?thanks   robp.s. will also take other end of motor off and check armature and commutator next week when cooler!
Reply:

Originally Posted by 12V71

No commutator on an A/C motor.
Reply:That cap is close enough, not critical.cg
Reply:I agree 👍 Dave

Originally Posted by chewinggum

That cap is close enough, not critical.cg
Reply:

Originally Posted by danielplace

That motor wouldn't have them.A/C motors though can have armature, commutator and brushes. Drills, angle grinders, sawzalls, skil saws, chop saws and many other A/C motors have them to name a few common ones in use we are all familiar with. https://chargedevs.com/features/a-cl...motors-in-evs/Grainger can get you the cap next day. https://www.grainger.com/product/6FL...234e42b8b79857
Reply:

Originally Posted by chewinggum

  That cap is close enough, not critical.cg