Finally Came Across Such A Complete Analysis Of The Internal Structure Of The Distribution Cabinet

The distribution box is a switchgear, measuring instrument, protective appliance and auxiliary equipment assembled in a closed or semi-closed metal cabinet or screen according to the electrical wiring requirements to form a low-voltage power distribution device.

Purpose of distribution box

It is easy to manage and facilitates maintenance when a circuit failure occurs. Power distribution boxes and power distribution boards of power distribution cabinets are complete sets of equipment that are centrally installed with switches, meters and other equipment.

There are two types of commonly used distribution boxes: wooden and iron plates. Nowadays, the electricity consumption is quite large, so iron is more used. The purpose of the distribution box: Of course, it is convenient for stopping and transmitting power, and it plays the role of measuring and judging the stop and transmission of power.

Composition of distribution box

It is mainly divided into two parts

The first is a complete set of components, that is, the distribution box shell and its related accessories.

The second is the electrical components and related accessories, that is, the air switch and its required accessories.

First, the circuit breaker

Circuit breaker: both switches, are the main components of the distribution cabinet, commonly used air switches. Leakage switches. Dual power automatic transfer switch

1. Air switch:

A. The concept of air switch:

The air switch is also an air circuit breaker. It is used to make, break, and carry rated operating current and short-circuit, overload and other fault currents in the circuit. For reliable protection.

Circuit breakers have different types of design, including dynamic and static contacts and contact rods, but improving the breaking capacity of the circuit breaker is the main purpose. At present, using a certain contact structure, the current limiting principle of limiting the short-circuit current peak value at the time of breaking has a significant effect on improving the breaking capacity of the circuit breaker, and is widely used.

B. Working principle of air switch:

Automatic air switches, also known as low-voltage circuit breakers, can be used to switch on and off load circuits, and can also be used to control motors that start infrequently. Its function is equivalent to the sum of the functions of some or all electrical appliances such as gate knife switches, overcurrent relays, voltage loss relays, thermal relays and leakage protectors. It is an important protective electrical device in low-voltage distribution networks.

Automatic air switch has a variety of protection functions (overload, short circuit, under voltage protection, etc.), adjustable action value, high breaking capacity, convenient operation, safety and other advantages, so it is currently widely used.

2. Leakage protection switch:

A. Leakage protection switch concept:

It has the leakage protection function, and the person who trips on the charged body will trip to ensure personal safety, which is the main function of the leakage protector; if the electrical equipment is not well insulated and leaks to the shell, the leakage protector will also trip to avoid human touch and electric shock. It also has current on-off function, overload protection and short-circuit protection.

B. Working principle of leakage protection switch:

The working principle of the leakage protector. LH is a zero-sequence current transformer. It consists of an iron core made of permalloy and a secondary coil wound around a ring-shaped iron core. The power phase line and neutral line pass through the round hole and become the primary coil of the zero sequence transformer. The output of the rear of the transformer is the protection range.

C, the role of leakage protection switch:

(1) When electricity leakage or ground fault occurs in electrical equipment or lines, the power can be cut off before people touch it.

(2) When the human body touches a charged object, it can cut off the power within 011s, thereby reducing the degree of harm to the human body caused by the current.

(3), can prevent fire accidents caused by leakage.

3. Dual power automatic transfer switch:

Concept: The dual power automatic transfer switch is one of two automatic power switching systems. After the first channel fails, the dual power automatic transfer switch automatically switches to the second channel to supply power to the load. If the second channel fails, the dual power automatic transfer switch automatically switches to The first way supplies power to the load.

Suitable for continuous power conversion of any two power sources such as UPS-UPS, UPS-generator, UPS-mains, mains-mains, etc.