What's Wrong with my Mark V Motor??

[JPG]

I hadn't seen the second link, thank you!

Is my logic above way off?

Only a little bit!

Without a start circuit, the motor usually just hums unless something external is nudging it.

If a start capacitor is 'open', there is no effective start circuit.

If a start capacitor is shorted, there will be no current phase shift in the start winding.

If a start switch is open, there is no effective start circuit.

If a start switch is shorted the start circuit will not 'disconnect' and the start winding will probably get hot. The start capacitor should be ok unless excessive voltage is developed across it.

Now about the 'low torque'. Without an effective start circuit, an induction motor will likely attempt to run, but will not have much torque if any, and the direction will be random. Excessive 'hum' will be present when power is applied and no rotation is taking place(very high current scenario).


So I would be suspicious of 'the start circuit' with the start switch the most likely culprit. A burned(shorted) start or run winding would be next(history dependent), then a loose wire or poor connection, and last the capacitor itself.

[joshh]

Good info as always sir

When I first acquired it, Skip Campbell and I changed the bearings together but I didn't know enough at the time to even ask about reversing it. Hind sight and all... I'm going to attempt reversing my motor today, and will hopefully make a step by step picture guide if all goes well. I might just succeed in making a paper weight instead though


P.S. sorry for the threadjacking...

[joshh]

How do I get in touch with Bill Mayo?

Scott

Did you get in touch with Bill? Are you going to attempt to diagnose and repair it, or are you going to replace the motor?




P.S. With an unsolicited email from Bill packed full of useful information, my motor now swings both ways. It also received new 12 gauge wire all the way into the motor! Guide with excellent pictures to follow soon. Thanks everyone

[Culprit]

Congratulations!

I look forward to the pictures. I'm curious to see where you chose to put the reversing switch. I like where I put mine but there is barely enough clearance on the inside without hitting the sheave and quill.

[JPG]

Congratulations!

I look forward to the pictures. I'm curious to see where you chose to put the reversing switch. I like where I put mine but there is barely enough clearance on the inside without hitting the sheave and quill.

I mounted mine on the motor pan near the upper left corner of the 'front'(side which faces the tail stock end). More clearance for wires which all run to the motor. Toggle switch handle 'up' for reverse.

[billmayo]

I put my FWD/REV switch 2" down and 2" in from the back edge of the motor pan. Should be directly under the ON/OFF switch. I bent the switch terminals 90 deg. for clearance.