What is the difference between a contactor and a starter? A contactor is an electrical switch used for switching current on and off in a circuit without overload protection. A starter is usually an assembly, that includes a contactor plus an overload relay, used to start an electic motor. Contactors are rated by their current in amps while starters are rated by their horsepower capacity and the current they use.
Definite purpose contactors are designed for applications including HVAC, i.e. air-conditioning compressor motor starting. DP contactors are also popular in food equipment, data processing and refrigeration industries. Definite purpose contactors are also generally designed for the intended life cycle of the application.