The Difference Between Fuse and Thermal Relay
Fuses, circuit breakers, and thermal relays are the three commonly used components for electrical control. It is mainly used as a protective electrical appliance in the circuit.
The fuse is also called a fuse, and the component file code is FU. It is an electrical component installed in the circuit to ensure the safe operation of the circuit. After the current exceeds the specified value for a certain period of time, the melt is melted by the heat generated by itself to cut off the power supply. Fuses are widely used in high and low voltage power distribution systems and control systems, as well as electrical equipment. They are mainly used as short-circuit and over-current protectors and are one of the most commonly used protection devices.
The circuit breaker is also called an air switch. The component text code QF. means that it can close, carry and break the current under normal circuit conditions, and can close, carry and break abnormal circuit conditions (including short circuit) within a specified time. Condition) of the current switching device. Circuit breakers can be used to distribute electrical energy, start asynchronous motors infrequently, and protect power lines and motors. They can automatically cut off the circuit when they experience serious overload, short circuit, and undervoltage faults. Its function is equivalent to a fuse switch Combination with overheating and underheating relays, etc. Moreover, it is generally not necessary to change parts after breaking the fault current. At present, it has been widely used.
Thermal relay, component text code FR. The working principle of the thermal relay is that the current flowing into the thermal element generates heat, which causes the bimetallic strips with different expansion coefficients to deform. When the deformation reaches a certain distance, it pushes the connecting rod to disconnect the control circuit, thereby causing the contactor to lose The main circuit is disconnected to realize the overload protection of the motor. Thermal relays are mainly used for overload protection of asynchronous motors. As an overload protection component of motors, they are widely used in production due to their small size, simple structure, and low cost.
