Thermal Overload Relay

Construction of thermal relay the construction of thermal relay is quite simple.

Thermal overload relay.

The bimetallic strip gets heated up by the current directly or indirectly and when the current flow exceeds the set value it bends. The function of a thermal overload relay used in motor starter circuits is to prevent the motor from drawing excessive current which is harmful to motor insulation. It is connected either directly to motor lines or indirectly through current transformers. The thermal overload relay can make up a compact starting solution together with contactors.

A thermal overload relay is a small electromechanical device that protects motors from overheating. These relays help to control the electrical current that goes to the motor to prevent it from overheating. A thermal overload relay works in the principle of electro thermal properties in a bimetallic strip. Thermal overload relay class 10 1 80 to 2 60a 690v lr2k0308 thermal overload relay class 10 1 80 to 2 60a 690v.

It is placed in the motor circuit in such a way that the current to the motor flows through its poles. It de energies the starter and stops the motor when excessive current is drawn. They offer reliable protection for motors in the event of overload or phase failure. The basic working principle of thermal relay is that when a bimetallic strip is heated up by a heating coil carrying over current of the system it bends and makes normally open contacts.

A thermal relay works depending upon the above mentioned property of metals. If the motor pulls too much electricity for an extended period of time the relay may flip and cut the power to the motor to prevent damage.