Motor Protection Circuit Breakers

A motor protection circuit breaker combines thermal tripping, adjustable to the motor current, with magnetic short-circuit tripping in a single housing, and can also be used to switch the motor on and off by hand. It is used at the outputs of three-phase asynchronous motors to protect against overload, phase loss and short circuits, mostly together with a contactor in a starter arrangement. The category includes the Schneider Electric TeSys GV2, GV3 and GV4, Siemens 3RV and 3MV, ABB MS116 and MS132 and Chint NS2 series; thermal setting ranges such as 7-10 A, 10-16 A and 45-63 A and breaking capacities such as 50 kA and 100 kA are stated in the product name or the technical table. Choose a thermal setting range that covers the rated current on the motor nameplate; also compare the short-circuit breaking capacity (Icu), screw or spring connection, and the auxiliary contact requirement. Models with magnetic tripping only do not include overload protection and are used together with a separate thermal overload relay. A miniature circuit breaker is not a substitute for a motor protection circuit breaker; because its thermal threshold is fixed, it cannot be set to the motor's rated current.

Products

How to choose Motor Protection Circuit Breakers

A motor protection circuit breaker combines thermal tripping, adjustable to the motor current, with magnetic short-circuit tripping in a single housing, and can also be used to switch the motor on and off by hand. It is used at the outputs of three-phase asynchronous motors to protect against overload, phase loss and short circuits, mostly together with a contactor in a starter arrangement.

  • Separate overcurrent/leakage protection, motor starting and local isolation requirements.
  • Select rated current, pole count and breaking capacity (kA) from the installation calculation.
  • Match coil voltage, auxiliary contacts and tripping curve to the control circuit and load type.

Frequently asked questions

What is Motor Protection Circuit Breakers and where is it used?

A motor protection circuit breaker combines thermal tripping, adjustable to the motor current, with magnetic short-circuit tripping in a single housing, and can also be used to switch the motor on and off by hand. It is used at the outputs of three-phase asynchronous motors to protect against overload, phase loss and short circuits, mostly together with a contactor in a starter arrangement.

What should I compare when choosing Motor Protection Circuit Breakers?

Choose a thermal setting range that covers the rated current on the motor nameplate; also compare the short-circuit breaking capacity (Icu), screw or spring connection, and the auxiliary contact requirement.

Which product groups are available under Motor Protection Circuit Breakers?

The current subcategories include Mounting Boxes. Open a subcategory to compare its products and technical details.

Motor Protection Circuit Breakers Selection Guide