Jointer motor woes (it works now)


So. Bad news bears today. The motor on the jointer isn’t working… just after I changed the knives. It was working earlier when I came in, then it just refused to turn over about 10 minutes later. I didn’t smell anything burnt, likely the coils are still fine (need to check resistance with multimeter). It hums and turns initially very slowly, then stops. The machine is easy to turn by hand, so there isn’t anything mechanically wrong with the machine as far as I can tell.

@imsofluffy and I checked the electrical wiring of the switch and the entry into the motor, both looked fine.

Low starting torque could be a problem with the start capacitor (it’s a single phase ac induction motor). I’ve pulled the cap out of the machine but haven’t figured out if it is a problem yet, I couldn’t find a multimeter which measures in the 300uF range. It isn’t shorted though.

I’ve left the cap on the top of the jointer along with an out of order sign. The next thing I’m planning is figuring out if this cap is indeed dead. If so, then replacement should be about $15-$20

If it isn’t, then the next suspect is the centrifugal switch. I was going to take the belt off and see if the motor will spin with no load or will spin after being turned over manually (need to figure out a way to do this safely).

If anyone had experience fixing single phase ac induction motors, I’m all ears.


So. After some troubleshooting, it seems the motor is ok.

The problem was/is that there is a lot of friction experienced when spinning the cutting head. It could be spun by hand but it would not free spin at all. A bit of WD40 fixed that problem.

Jointer runs again. Yay.

The End.


Wow - that is awesome. Thanks for checking everything out and fixing it!