# Need Capacitor Information for Craftsman Air Compressor



## Ogogo

Good afternoon,

I have been looking for better part of this afternoon for the capacitor information for this motor. I have found multiple parts manuals but none detail the capacitors. This one appears to have a run and start capacitor. A.O. Smith appears to have stopped making AC motors in 2014 and cant find information on Century's website. I have pump aasy numbers and main Motor Part numbers, just no breakdown or details of the capacitors cause im going to have to by them aftermarket. 

Compressor is tripping breaker on restart. Tested both capacitors and one is open. The other appears to have been replaced, just want to make sure it is correct.

Thank you in advance.

Pump assy: Z-D24959
I think this is the run capacitor: K-0298
I think this is the start capacitor: D29142


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## stevon

Ogogo,

I would discharge the capacitors then mark the wires as to which capacitor they go to (eg 54mfd 300 volt) then remove them to see what the MFD or UFD they are marked and search for replacement capacitors. You do not need "A.O. Smith" brand capacitors you only need the same rating and physical dimention replacement capacitors. Are the capacitors "bulging" or leaking something? they can be tested, why do you think they are bad?

Testing:


how to test motor capacitor - Google Search



Replacement (requires matching specs):








Amazon.com: A. O. Smith Start Capacitor, 53-64 MFD, 230v, 1-7/16" x 2-3/4" : Industrial & Scientific


Amazon.com: A. O. Smith Start Capacitor, 53-64 MFD, 230v, 1-7/16" x 2-3/4" : Industrial & Scientific



www.amazon.com





Stephen


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## Ogogo

I tested both. The one that I believe is the run capacitor tested good (Pic below) appears to have been replaced and want to make sure it is the correct size. The other is (OL) when tested with the meter. No spike and discharge. But the foam padding on the capacitor to reduce vibration noise from the motor rusted the numbers off. Very bad placement.

When initially powering up and turning on the compressor runs fine. When it is time for autorun to kick in the compressor hums and the breaker trips

I wanna say the 161 - 193 uF for a start capacitor is correct but I think the 250VAC is throwing me off. It is a 120 VAC system. It has been a many years since I touched capacitors as an HVAC repair technician, I have forgotten the basics.


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## stevon

Ogogo,

Capacitors are rated for higher voltage because peak or RMD voltage is more than the use voltage and a safety buffer (higher breakdown voltage) is needed. The run capacitors are 370 or 440 volts.
This web site will give you an idea what you need:



Electric Motor Starting Capacitor Selection Select an A/C Compressor & Other Electric Motor Start-Boost Capacitors



Stephen


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## stevon




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## Ogogo

That answered my question. Many many thanks for that. I will order what I need and let you know the outcome


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## stevon

Ogogo,

your motor is 1.5 HP output, never mind that 3.5 "developed" HP marketing B.S. I think a 30 MFD 370 volt run capacitor should work. A trip to your local Graingers should solve your issue.

Stephen


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## stevon

Ogogo, 

a cheap Harbor freight clamp on style ammeter should point you in the right direction

Stephen


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## Ogogo

Good evening. I didn't know much about air compressors until I got this one. The issue ended up being trash in the check lve coming from the motor causing it to airlock. I did replace the bad capacitor and it runs s like a champ now.


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## iowagold

sorry too late to the party.
I did find a real good supco brand cap tester
click here for the repair tools page
it is about 3/4 the way down the page.
perfect for finding the out of spec caps on motors and gen sets!


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## smith77

The charge storing capacity of different capacitors are different and if you are looking out for electronic components then go to industrial electronics repair


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