https://www.tgautoparts.com/1. Function:

• Contactor: A contactor is an electrical switching device used to control the flow of electricity in a circuit. Its primary role is to switch power on and off to a load (typically motors, heaters, lighting circuits, etc.) by opening or closing electrical contacts.
• Motor Starter: A motor starter is a specialized type of contactor designed to not only switch the motor on and off (like a contactor) but also provide overload protection for the motor. It prevents damage to the motor by cutting power when the motor draws excessive current or overheats.

2. Components:

• Contactor: Consists of just an electrical coil and contacts that open or close to control the flow of electricity. It does not have any overload protection.
• Motor Starter: Contains a contactor for switching, but it also includes an overload relay (thermal or electronic) that monitors the current and shuts down the motor if it overheats or operates outside its current rating.

3. Overload Protection:

• Contactor: No overload protection. It is simply used for switching power to the motor or other loads.
• Motor Starter: Includes overload protection, typically via an overload relay, which safeguards the motor from excessive current draw.

4. Application:

• Contactor: Used in a wide range of electrical applications where on/off control is needed for any electrical load (lighting, HVAC, motors, etc.).
• Motor Starter: Specifically designed for controlling and protecting motors, ensuring both switching and protection functions in motor control circuits.

In summary, a motor starter is a contactor with added overload protection, making it a more specialized device for motor applications.