# Capacitor issue



## dronai (Apr 11, 2011)

Does that say 25 uf ? What are you measuring it with ?

Lots of those online for very cheap


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## joebanana (Dec 21, 2010)

Just about any 300VAC, 25 micro-farad motor start cap. should do.


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## Southeast Power (Jan 18, 2009)

Take it to a mechanical supply house and they will match it up for you.


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## hardworkingstiff (Jan 22, 2007)

https://www.grainger.com/product/DAYTON-Run-Capacitor-2MEC8


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## MechanicalDVR (Dec 29, 2007)

Nothing special about a 25uf cap.

370v or 440v will do just fine.


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## JRaef (Mar 23, 2009)

But... 9 times out of 10 if the cap is truly bad, it will be swollen or leaking goo. More often the problem is the centrifugal switch on the end of the motor. The switch has to be CLOSED WHEN STOPPED, and the contacts open at roughly 75-80% speed. If the contacts get stuck open or the points are burned off, you get exactly what you are experiencing. 

Because a fan motor ends up IN the air stream, it gets subject to all the gunk and grit that is pulled in with it. That crap builds up on the centrifugal switch and makes it stick. I've seen it a few dozen times. Spray it with a little CRC contact cleaner, let it dry off and POOF, it works!


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## Jeff B (Sep 30, 2017)

JRaef said:


> But... 9 times out of 10 if the cap is truly bad, it will be swollen or leaking goo. More often the problem is the centrifugal switch on the end of the motor. The switch has to be CLOSED WHEN STOPPED, and the contacts open at roughly 75-80% speed. If the contacts get stuck open or the points are burned off, you get exactly what you are experiencing.
> 
> Because a fan motor ends up IN the air stream, it gets subject to all the gunk and grit that is pulled in with it. That crap builds up on the centrifugal switch and makes it stick. I've seen it a few dozen times. Spray it with a little CRC contact cleaner, let it dry off and POOF, it works!


Dead on!

The centrifugal switch opens at speed to effectively remove the cap from the circuit. Fouled contacts from air stream funk and a binding armature will cause behavior that mimics an open cap. Best to confirm proper operation of both before testing again under power.


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