All Replies on Jointer motor humming, not running...Help

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View John_G's profile

Jointer motor humming, not running...Help

by John_G
posted 01-15-2018 01:31 AM

4 replies so far

View WhyMe's profile


1309 posts in 2406 days

#1 posted 01-15-2018 01:36 AM

Centrifugal switch is not engaging which connects the capacitor or capacitor is bad. Check the cap with a tester.

View Loren's profile


10566 posts in 4493 days

#2 posted 01-15-2018 01:42 AM

Try taking the belt off, turning it on and
spinning the sheave by hand. Sometimes
the motor will pick up and go. Leave it
running for 15 minutes. Turn it off and on
again and see if it starts on its own.

View JohnMcClure's profile


1073 posts in 1485 days

#3 posted 01-15-2018 02:30 AM

Agreed with both above. You can verify that it’s the cap or centrifugal switch by doing Loren’s suggestion; if a hand-start gets it to pick up, the failure is in the cap or centrifugal switch. If a hand-start won’t get it running, something else could be going on. Like an open in the run winding – you can check that with an ohmmeter. Should be less than 3 ohms resistance, typically less.

-- I'd rather be a hammer than a nail

View splintergroup's profile


3977 posts in 2067 days

#4 posted 01-15-2018 03:45 PM

Try the hand spin up test (if safe for you) first. If the motor is not totally enclosed TEFC (totally enclosed, fan cooled), you may have gotten some sawdust inside that is blocking the centrifugal switch. Give it a good blow out with compress air.

Start capacitors live in the “hump” cover on the side of the typical motor. Easy to access, at least for a quick visual inspection of any burning or swelling.

A humming motor that won’t spin up is almost always one or both of the mentioned parts.

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