Electrical appliances are divided into the following five categories according to their functions. According to its function in the circuit, it can be divided into control type electrical appliances and protection type electrical appliances

Electrical appliances are divided by function, mainly including the following five categories:

1. Electrical appliances for connecting and breaking circuits, such as contactors, knife switches, load switches, disconnectors, circuit breakers, etc.
2. Electrical appliances used for control circuit, such as electromagnetic starter, auto coupling decompression starter, rheostat, control relay, etc.
3. Electrical appliances used for switching circuits, such as change-over switches, master devices, etc.
4. Electrical appliances used to detect circuit coefficients, such as transformers, sensors, etc.
5. Electrical appliances used to protect circuits, such as fuses, circuit breakers, lightning arresters, etc.

According to its function in circuit

1. Control electrical appliances: including contactors, switch electrical appliances, control relays, master electrical appliances, etc. It mainly plays the role of control and conversion in the circuit.
2. Protection appliances: including fuse, thermal relay, over-current relay, under voltage relay, over-voltage relay, etc. It plays a protective role in the circuit.