Thermal magnetic circuit breakers are automatically operated electrical switches that protect against overcurrent in circuits. These circuit breakers have a simple mode of operation; they rely on two switching mechanisms (an electromagnet and a bimetallic strip) to provide protection against overcurrent in circuits.

The electromagnet is sensitive to large surges in electrical current and responds by shutting off the flow of electricity to the component. In contrast, the bimetallic strip expands when exposed to excessive electrical currents. This causes the strip to bend toward a trip bar that turns the circuit off. When current levels return to normal, the strip cools down and reset, allowing normal operation to continue.

Circuit breakers that feature bimetallic strip offer time-delayed protection, while those with electromagnets offer instantaneous protection. Because a thermal-magnetic circuit breaker combines these two technologies, it is able to provide both instantaneous and time-delayed protection depending on the particular application. For example, instantaneous protection is suitable for interrupting extremely high currents that could become fatal, whereas time-delayed protection is needed in electrical equipment that temporarily draws currents that exceed their rated values.

Ambient and Installation Conditions

● Altitude up to 2000m;
● Ambient medium temperature should be within -5℃ to +40℃ (+45℃ for marine products);
● It can withstand the effect of damp air;
● It can withstand the effect of moulds;
● It can withstand the effect of nuclear radiation;
● The max inclination is 22.5℃.
● It still can work reliably when the ship subjects to normal vibration;
● It can still work reliably if the product subjects to the earthquake (4g).
● Places where the surrounding medium is free from explosion danger, and far away from gas or conductive dust that would erode the metal or destroy the insulation;
● Keep away from rain or snow.

Components of Circuit Breaker