Dead motors

[John T Barker]

When a motor goes out is it dead or just in a coma? How does one know. I have a '50's Powermatic planer that the motor conked out on and I'm wondering if it can be revived. (Know precious little about electric)

[Richard Coers]

If it's more than a simple 1/2hp, I take it to a motor shop. IF, I've already checked the start and run capacitor and the centrifugal start switch. It's very common for the start capacitor to fail first.

[Doug Garson]

Before taking it to a motor shop, which is good advice if you are not experienced with electrical, first check to confirm power is getting to the motor. Starting at the panel, make sure the breaker isn't tripped, the plug isn't ajar. Maybe plug something else in the outlet to see if it works. Unplug it and open up the switch box, check for build up of sawdust. I had a jointer quit and the problem was a piece of paper from the wiring diagram inside the switch box broke off and ended up in the switch contacts. After this, you want to check if there is power after the switch. At this point you probably need a multi meter to check for continuity, still unplugged, across the switch with the switch on or with the unit plugged in check for power after the switch.

[Bill Dufour]

When I replace a motor I like to cut the power cord near the motor. Then add a new short cord with a plug. Then attach a matching female receptacle to the old power cord. The two cord ends have to match each other. No need to match anything else in the shop. so a good use for oddball cord ends kicking around.
This makes trouble shooting much easier and no more standing on my head to wire up the replacement motor.
BillD

[Michael Schuch]

If it's more than a simple 1/2hp, I take it to a motor shop. IF, I've already checked the start and run capacitor and the centrifugal start switch. It's very common for the start capacitor to fail first.


I would guess that half of the dead motors I have encountered have just been bad capacitors which are usually a pretty easy fix. I even walked my little sister through removing the capacitor from her whole house fan, reading the capacitance off the dead capacitor, ordering a new one from Amazon and wiring the new capacitor back in. That was at least 10 years ago and the fan is still running fine. We bought a Sprague capacitor to replace the cheap Chinese capacitor.

I have a nice 7.5 hp 3 phase motor that is dead, dead which I picked up for free. I need to check out the windings one of these days and sell it for copper value if I can't find a simple open somewhere. It didn't smoke when it died so I might get lucky.

[Tom M King]

Probably only mostly dead.

https://www.youtube.com/watch?v=xbE8E1ez97M

[mike calabrese]

The capacitor is an easy fix if that is the issue. On the centrifugal start switch I have had experience where these fail simply due to saw dust getting in and screwing the action up. The fix it turns out is simply to blast it with compressed air.
If you need to replace the motor you may find something here.
https://electricmotorwarehouse.com/?gad=1&gclid=EAIaIQobChMI9fqW_aa0ggMVwExHAR33IwdEEAAYASAA EgL5SfD_BwE
calabrese55

[Patty Hann]

Probably only mostly dead.

https://www.youtube.com/watch?v=xbE8E1ez97M

I love that movie ;)

[Brian Runau]

If not a capacitor, bearing, etc... problems in the copper windings causing electrical problems generating the +/- relationship to get the motor to turn. When I retired 4 years ago, for a std frame motor, they did not rewind 10 hp and under, it was cheaper to replace them. Motor shop can rewind most motors, just how much you want to pay. Brian

[Bill Dufour]

Start switches can be replaced by a universal solid state timer thing.
Bill D

[Bill Howatt]

... When I retired 4 years ago, for a std frame motor, they did not rewind 10 hp and under, it was cheaper to replace them. Motor shop can rewind most motors, just how much you want to pay. Brian

Basically the same message I was given at a motor shop a few years ago.