Reversing Drum Switch And Split Phase Start Cap Motor
The 1/2 H.P. 120 volt motor on my lathe finally kicked, it was only the start winding points that got fried, but the motor was so dirty and greasy, and it had overheating issues, so I got a new one.
I looked at the old drum switch, and it was pretty ratty, so I got a new one. A friend gave me the motor, and I picked up the drum switch from Grainger for about sixty dollars with tax.
The only problem was that I did not have a schematic for the motor and rather than guess and fry the start winding points I figured I would take it apart and I am glad I did. The main lug that I would normally attach the power in, was also tied to the start winding points. So I had to take the two leads off that fed the two-run windings and connect them directly to the neutral out from the drum switch. And then run one of the alternating/reversing, start winding leads out from the drum switch to the main lug on the motor. And then connect the start winding lead from the motor to the output of the start winding points. It worked perfectly. If you ever have to do one, this could save you from frying the points with a direct short. This drum switch only requires four wires from the switch to the motor but you should have a ground too.
Sincerely,
William McCormick
If I wasn't so.....crazy, I wouldn't try to act normal, and you would be afraid.