Pool Motor Types

There are five distinct electrical designs that are commonly found on swimming pool and spa pumps.

1. Split Phase. This type of single-phase motor is used extensively in spa and jetted tubs and above ground pool applications. Some are used on pumps on the lower end of the in ground pool market. This design has a start winding and a start switch, but no capacitors.
2. Capacitor Start. This is a very common single phase motor found on in ground pool pump applications. The starting torque is higher (150-175% of full load) and starting current lower than the split phase equivalent. The operation is similar to a split phase in that there is a start switch to take the start winding and capacitor out of the circuit once the motor reaches 2/3 to 3/4 of full speed.
3. Permanent Split Capacitor. This design does not have a start switch and is often referred to as a “switchless” motor. It uses a run capacitor that remains in the circuit at all times. The PSC design has significantly less starting torque than the capacitor start design.
4. Capacitor Start/Capacitor Run. This design is used to increase efficiency in run mode. Both start and run capacitors are used. In run mode, PSC and Cap. Start/Cap. Run motors are the same.
5. Three phase (Polyphase). This is the simplest, most efficient design. Its use is limited to commercial and industrial applications because three phase power is not available in residential areas.