An overload relay device is used to open the circuit in thermal, electrical, or power overload. Also known as relay switches, they are generally close and only used in situations of overload.
Overload relays sense current in the motor and protect it by controlling current, for example, in short circuits, ground faults, short circuits, phase failures, mechanical jamming, etc. Relays cut off the current to the motor when high. These overload relays are used for small heaters, bi-metallic elements, etc.
BCH electric limited offers two types of overload relays, thermal and electronic. Where OLR works on the principle of bimetallic strip deformation on heating, electronic overload relays work on microprocessors.