BR-B series thermal overload relay/motor thermal protection switch is mainly designed for the electricity protection system of single-phase AC motor incase of some abnormal working conditions like overload or stalling. It features small volume and high sensitivity. Apart from applications in motor, the bimetal thermostat is also seen in battery, air conditioner motor, and automotive seat heating system, etc.
Differing from BR-A1D series thermal protector which adopts casings made from stainless steel, BR-B2D series employs insulated plastic enclosure. It stimulates a rapid change of the bimetal's condition which result to the separation of 2 contacts and thus cutting off the circuit, barely relying on the bimetal's temperature sensing and the current thermal effect.
Under normal condition, for a thermal switch, when the temperature rises to the max point, the 2 contacts will separate and the switch is open. On the contrary, when the temperature drops to the allowable range, the contacts touch and the switch is closed.