U.S. Seal Run Capacitor 25 MFD 370V Round, RD-25-370

This is the U.S. Seal RD-25-370, a round run capacitor rated at 25 MFD and 370 volts. It is a replacement motor capacitor for pool pump motors.

What a run capacitor does

A single phase motor cannot get itself turning without help. The capacitor supplies the phase shift that starts it, and a run capacitor stays in circuit the whole time the motor is spinning to hold that shift. It is one of the more common failures on a pool pump and one of the cheapest to put right.

Matching the part

Two numbers decide the fit. The capacitance in microfarads has to match what the motor was built for, because a different value changes how the motor behaves under load. The voltage rating can be equal to or higher than the original but never lower. Check the case shape too, since this is the round style and it has to sit in the mounting the motor provides.

Safety

A capacitor stores energy and can stay charged long after the power is switched off. Turn off the breaker, discharge the old capacitor safely, then disconnect it. If that is not something you are set up to do, hand the job to a service technician.