MM20/SP500 bandsaw, motor dead?

[Barry Versteegh]

After you push start control check for voltage on t1 and t2 on load side of contactor. You should see 240 volt , if you check neutral to t1 and t2 you will see 120 volt the same leg of the power, if one side of your contactor is open you will not 240 volt going to motor, but you will have 120 volt to neutral on both load side of the contactor.

[Bill Dufour]

It should at least hum if either run or start windings are getting power. I suspect terminal wire or screws inside motor are loose. Pass enough current for meter to move not near enough for power.
Tighten/wiggle every connection on the motor board. If no luck remove board and check solder connections to back of the board.
Bill D

[Brian Holcombe]

Connections are all tight. I’m getting 120v because I’m checking one leg to neutral at a time.

I’ll check to see if the switch is stuck open.

[Bill Dufour]

You need to check leg to leg and verify 240 volts. Maybe something changed and you are using the same phase on both legs. To be honest I do not see anyway that could happen downstream of the meter.
Bill D

[Tom M King]

If the motor is getting 240, it ought to say something.

[Dan Friedrichs]

Brian, you said you have 240V across the motor (or, at least you suspect you do because you have 120V between each leg and ground).
You also said you have 0.7ohm across windings.
If both of those things were true, you'd have 340amps flowing. Clearly you don't, so one of those things is wrong.

I'd investigate further. I think you're going to spend more time and money swapping to 3phase than if you just find the loose wire or whatever.

My guess is that you have one leg open on the contactor or overload. This is connecting 120V to one side of the motor, but leaving the other side floating. Since the motor is just a coil of wire, you're measuring the "same" 120V on both sides, but if you measured across both leads, you'd have 0V (not 240V).

[Erik Loza]

Of all the bizillion MM’s I sold, cannot ever recall a bad motor. Not saying it’s impossible, but would be extremely unexpected. Hope you get ot sorted out quickly.

Erik

[Brian Holcombe]

Dan, just measured as you suggested and you are correct it shows 0v across the terminals but 120v at each individually.

[Tom M King]

How about on the power in lugs on the switch?

[Dan Friedrichs]

Dan, just measured as you suggested and you are correct it shows 0v across the terminals but 120v at each individually.

So you don't have a motor problem. You have a problem in the switch or overload. Somehow you aren't getting power through to the motor.

Unplug, manually hold the contactor down, and check continuity through.

[Brian Holcombe]

I checked the centrifugal switch and it appears to be functional.

[Dan Friedrichs]

It is one of these switches? http://www.solowoodworker.com/mm/switch.html

My guess it that you have 240V on the input to the switch, but 0V on the output (only one leg of the 120V is getting through). I don't think it has anything to do with the motor.

[Tom M King]

That's why I suggested to test the power in to the switch (on/off switch). You have already determined 240 is not getting out. To test the switch, all that's left is to see what's getting in to it.

[Brian Holcombe]

I checked the switch and it was showing 120v at both legs on the output. Is this a faulty testing method?

[Brian Holcombe]

Dan, that page won’t load for me, it’s an Eaton starter/switch.