Low-voltage drawer switchgear

Low-voltage drawer switchgear is an electrical equipment widely used in low-voltage power distribution systems. Here is a detailed introduction to it:

I. Structural characteristics

1. **Drawer-type unit structure**

- Low-voltage drawer switchgear adopts a drawer-type design. Each functional unit is installed in an independent drawer. This structure is convenient for installation, maintenance and repair. For example, when a fault occurs in a certain circuit, the faulty drawer can be directly pulled out for maintenance without affecting the normal operation of other circuits.

- The drawer has a reliable mechanical interlock device. During the operation, only when the drawer is in the correct position (such as test position, working position or separated position), can the corresponding operation be performed to prevent safety hazards caused by misoperation.

2. **Cabinet structure**

- The cabinet is generally made of high-quality cold-rolled steel plate and is processed and formed by numerical control processing equipment, with high precision and strength. The surface of the cabinet is usually treated with electrostatic spraying, which is beautiful and can prevent the cabinet from rusting.

- The internal layout of the cabinet is reasonable and is divided into different compartments such as busbar room, functional unit room (drawer room) and cable room. The busbar room is used to arrange the main busbar and provide power for each functional unit; the functional unit room is used to install drawer-type functional units; the cable room is used to connect incoming and outgoing cables.

II. Functions and uses

1. **Power distribution function**

- Low-voltage drawer switchgear plays a role in distributing electric energy in low-voltage power distribution systems. It can distribute the input low-voltage electric energy to various branches to meet the power consumption needs of different loads (such as lighting, power equipment, etc.). For example, in the low-voltage power distribution system of a factory, it can distribute the low-voltage electricity from the transformer to the electrical equipment in various workshops, offices and other areas.

2. **Protection function**

- The internal functional units (such as circuit breakers, fuses, etc.) can protect the circuit from overload, short circuit, undervoltage, etc. When overload or short-circuit current occurs in the circuit, the circuit breaker will trip automatically to cut off the faulty circuit and protect the safety of equipment and lines; when undervoltage occurs, the undervoltage protection device will act to prevent the equipment from operating abnormally under low voltage.

3. **Control function**

- It can perform control operations on some equipment. For example, the start, stop, forward and reverse rotation control of equipment such as motors is realized through elements such as contactors. At the same time, some intelligent low-voltage drawer switchgears can also realize remote control and monitoring functions, which is convenient for centralized management of the power distribution system.

III. Main components

1. **Circuit breaker**

- It is an important protection and control element in low-voltage drawer switchgear. It can connect and disconnect the circuit under normal conditions, and quickly cut off the current when the circuit has faults such as overload and short circuit. There are common molded case circuit breakers and miniature circuit breakers. Molded case circuit breakers are suitable for circuit protection with large current, while miniature circuit breakers are mostly used for branch protection with small current.

2. **Fuse**

- It is mainly used for short-circuit protection. When a short-circuit fault occurs in the circuit, the fuse element of the fuse melts and cuts off the current to prevent the fault current from causing further damage to the equipment and lines.

3. **Contactor**

- It is used to control the start, stop and forward and reverse rotation operations of loads such as motors. The contactor realizes the control of the circuit by closing or opening the contacts through the action of electromagnetic force.

4. **Thermal relay**

- It is mainly used for overload protection of loads such as motors. It detects the overload condition according to the heat generated when the current passes through. When the overload reaches a certain degree, the thermal relay acts to make the contactor disconnect the circuit and protect the load equipment.

IV. Application fields

1. **Industrial field**

- Widely used in various factories, such as machinery manufacturing factories, chemical factories, electronics factories, etc. It is used to provide stable power distribution and protection for various production equipment (such as machine tools, reaction kettles, electronic equipment production lines, etc.).

2. **Commercial buildings**

- In commercial buildings such as shopping malls, office buildings and hotels, low-voltage drawer switchgear provides power distribution and protection for equipment such as lighting systems, air conditioning systems and elevators.

3. **Infrastructure**

- In infrastructure such as airports, railway stations and subway stations, it provides power guarantee for various electrical equipment (such as lighting, ventilation, communication and other equipment).