What is a fuse and its classification

A fuse (fuse) refers to an electrical appliance that melts and disconnects the circuit by using its own heat when the current exceeds a specified value. The fuse means that after the current exceeds the specified value for a period of time, the melt is melted by its own heat and the circuit is disconnected; the current protector made by this principle. Fuses are widely used in high and low voltage power distribution systems, control systems and electrical equipment. As a short circuit and overcurrent protector, it is one of the most widely used protection devices.
Working principle: The metal conductor is used as the melt in series in the circuit. When the overload or short-circuit current passes through the melt, it will fuse due to self-heating, thus breaking the circuit. The fuse has a simple structure and is easy to use, and is widely used as a protection device in power systems, various electrical equipment and household appliances.
Fuses can be divided into high-voltage fuses and low-voltage fuses according to the voltage used. According to the protection object, it can be divided into fuses to protect transformers and general electrical equipment, fuses to protect voltage transformers, fuses to protect power capacitors, fuses to protect semiconductor components, fuses to protect motors, and fuses to protect household appliances . According to the structure, it can be divided into open type, semi-closed type, tubular type and spray type fuse.
In addition, fuses can be divided into general-purpose fuses, backup fuses and full-range fuses according to the breaking current range. The breaking current range of general-purpose fuses refers to the range from 1.6 to 2 times the overload current to the maximum breaking current. Such fuses are mainly used to protect power transformers and general electrical equipment. The breaking current range of the backup fuse refers to the range from the overload current 4 to 7 times higher than the rated current to the maximum breaking current. This fuse is often used in series with the contactor. When the overload current is less than 4 to 7 times the rated current, the contactor will achieve breaking protection. Mainly used to protect the motor.
With the needs of industrial development, special fuses suitable for various requirements such as electronic fuses, thermal fuses, and self-resetting fuses are also manufactured.

Post time: Aug-16-2022