Motors are used in a wide variety of applications and are consequently subjected to many and various loads. Motor-protection switches from ABB offer appropriate protection for every application: MS225 and MS325 up to 25 A, MS450 up to 50 A and MS495 up to 100 A are used for standard tasks.

Wherever particularly heavy short-circuit currents have to be coped with, the high-power MS325 and MS497 (up to 25 A and 100 A respectively) are in their element: with short-circuit breaking capacities of I_SC = 50 to 100 kA, these devices can be operated at 400 V in practically all applications without a back-up fuse.

Further models supplement the range: among the motor-protection switches, up to 50 A and 100 A there are also devices of tripping class 20 for the protection of high-inertia starters. In every current range, there are also pure "short-circuit-protection switches" available, i.e. circuit-breakers without thermal protection. They are used wherever a separation of thermal and magnetic tripping is called for (e.g. automatic restarting).

Last but not least, GS325 should be mentioned: device for the protection of small single-phase control transformers. The transformer is protected against short-circuits on the primary side with GS325, and on the secondary side is protected against short-circuit and thermal overload.