The difference between a contactor and a motor starter is:

The difference between a contactor and a motor starter is:

• A. physical size
• B. overload protection
• C. wire size
• D. timing

Answer: (B)

Overload protection is the key difference. A contactor is mainly a heavy-duty switch that opens or closes the motor circuit under control, with no built-in protection for overcurrent. A motor starter combines that switching function with motor protection, typically including an overload relay or thermal protector that trips if the motor draws excessive current or overheats. That protection is what makes a motor starter capable of safely starting and running a motor without risking damage. Size, wire gauge, or timing can vary with the specific device and application, but they don’t define the fundamental distinction.

Overload protection is the key difference. A contactor is mainly a heavy-duty switch that opens or closes the motor circuit under control, with no built-in protection for overcurrent. A motor starter combines that switching function with motor protection, typically including an overload relay or thermal protector that trips if the motor draws excessive current or overheats. That protection is what makes a motor starter capable of safely starting and running a motor without risking damage. Size, wire gauge, or timing can vary with the specific device and application, but they don’t define the fundamental distinction.