Pool Pump Motor Question

[Todd]

I have a 3/4 HP pool pump motor that has a centrifugal switch in it. The start windings have gone bad so it will not start on its own but will run fine if I "give it a hand" to get started. My question is can I put a start capacitor on the main windings to get it going? Will it work? What size capacitor should I try? Capacitor are far cheaper than pool pumps so giving it a try would be a low bux solution. Here are the details

3/4 HP 115 VAC 3450 RPM 8.5 A Continuous Duty Service Factor 1.0 (BTW, what does the "service factor" # indicate?

Thanks for the info. Todd

[Dave Martindale]

If the winding is bad, the motor is dead.

Capacitor-start and capacitor-run motors put the capacitor in series with a second winding. The capacitor causes a phase shift in the current in the second winding so that the magnetic fields of the (unshifted) main winding and the second winding (added together) rotates. A split phase motor gets the phase shift by making the second winding higher resistance or higher inductance, without a capacitor.

But all of these methods need the second winding to work. With one single winding, there is no rotating magnetic field, just a pulsating one. That will keep the motor rotating once started, but won't start it. A capacitor on the main winding will cause a phase shift with respect to incoming power, but there's still no rotating field.

He's dead, Jim - unless you get a motor shop to repair or rewind the start winding.

Dave