What is the difference between a motor starter and a contractor?

• A. They are identical
• B. A starter has an overload protection device
• C. A contractor has overload protection
• D. A motor only

Answer: (B)

The key idea is that a motor starter is a complete control assembly that protects the motor while starting or running it. A motor starter combines a controllable switch (the contactor) with an overload protection device. The overload protection senses motor current and trips if the motor overheats, guarding against damage during startup or overload conditions. A contractor (contactor) by itself is just the switch that energizes or de-energizes the motor circuit and does not include protection. So the statement that a starter has an overload protection device captures the essential difference. In practice, if you only used a contractor, you’d need a separate overload relay to provide protection.