busted motor question

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Forum topic by Loren posted 12-21-2011 07:21 AM 685 views 0 times favorited 2 replies Add to Favorites Watch
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8159 posts in 3068 days

12-21-2011 07:21 AM

I have a 240v motor on my bench I got with some other stuff.
I wired it up and got it to buzz and turn very slowly for about 4
seconds before it blew its overload circuit. Now it seems dead.

I took out the capacitor and it looks okay, but would the next step
be to try to find my voltage meter and test the capacitor?

I guess my alternative is to take the capacitor to a motor shop and
ask them to test it and buy a replacement if it is bad.

There is a dusting of rust around a portion of the rim of the capacitor
which may indicate something awry inside I suppose.

2 replies so far

View TCCcabinetmaker's profile


930 posts in 1775 days

#1 posted 12-21-2011 07:29 AM

Slow turning, buzzing. Not good, usually does mean somethings amiss in the moter casing.

-- The mark of a good carpenter is not how few mistakes he makes, but rather how well he fixes them.

View ajosephg's profile


1878 posts in 2981 days

#2 posted 12-21-2011 11:08 AM

Capacitor could be bad even though it looks good.

If you have a volt/ohmmeter you can check it as follows.

With the capacitor disconnected from the motor, put your meter on the ohms setting at R x 1000. Hook the meter test leads to the capacitor terminals. The meter should show a low resistance and rapidly increase to a very high reading. Quickly disconnect the meter leads and reverse them on the capacitor terminals. If you have an analog meter, the needle will peg out left of zero and rapidly increase to a very high reading. I’ve never done this with a digital meter, but it may show a negative reading followed by a very high positive reading.

If these things don’t happen, replace the capacitor. If the capacitor is good, you have a winding problem, or if the motor has a starter switch, it could be malfunctioning due to foreign material, broken spring, or bad contacts.

-- Joe

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