Analysis Of The Internal Structure Of The Most Complete Power Distribution Cabinet

"Distribution box", also called power distribution cabinet, is the collective name for the motor control center. The distribution box is to assemble the switchgear, measuring instruments, protective appliances and auxiliary equipment in a closed or semi-enclosed metal cabinet or on a frame according to the electrical wiring requirements to form a low-voltage power distribution device.

The purpose of the distribution box?

It is easy to manage and facilitates maintenance when a circuit failure occurs. Power distribution boxes and power distribution cabinets, power distribution panels, power distribution panels, etc., are complete sets of devices for centralized installation of switches, meters and other equipment.

Commonly used distribution boxes are made of wood and iron plates. Nowadays, the electricity consumption is quite large, so iron is used more. The purpose of the distribution box: Of course, it is convenient to stop and transmit electricity, and play a role in measuring and judging the stop and transmission of electricity.

The distribution box is mainly divided into two parts

One is the complete set of parts, namely the enclosure of the distribution box and its related accessories.

The second is electrical components and related accessories, that is, air switches and the accessories they need.

The cabinet is composed of the following parts:

One, circuit breaker

Circuit breaker: switch, is the main component of the power distribution cabinet, commonly used are air switch, leakage switch, 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 for making, breaking and carrying rated working current, short circuit, overload and other fault currents in the circuit, and can quickly break the circuit in the case of overload, short circuit, undervoltage, etc. of the line and load. For reliable protection.

The design of dynamic and static contacts and rods of circuit breakers are diverse, but improving the breaking capacity of circuit breakers is the main purpose. At present, the current limiting principle of using a certain contact structure to limit the peak value of short-circuit current during breaking has an obvious effect on improving the breaking capacity of the circuit breaker, and is widely used.

B. Working principle of air switch:

The automatic air switch is also called a low-voltage circuit breaker, which can be used to connect and break the load circuit, and can also be used to control a motor that starts infrequently. Its function is equivalent to the sum of part or all of electrical appliances such as knife switch, over-current relay, voltage loss relay, thermal relay and leakage protector, and is an important protective electrical appliance in low-voltage distribution networks.

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

2. Leakage protection switch:

A. Leakage protection switch concept:

It has the function of leakage protection. The main function of the leakage protector is to ensure personal safety. If the electric equipment is not insulated well, the leakage protector will also trip to avoid human touch and electric shock. At the same time, it has current on-off function, overload protection and short-circuit protection.

B. Working principle of leakage protection switch:

The working principle diagram of the leakage protector. LH is a zero-sequence current transformer, which consists of an iron core made of permalloy and a secondary coil wound on the ring-shaped iron core to form a detection element. The power phase line and the neutral line pass through the circular hole to become the primary coil of the zero sequence transformer. The back of the transformer is the protection range.

C. The role of leakage protection switch:

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

2. When the human body touches a charged object, the power supply can be cut off within 011s, thereby reducing the damage to the human body by the current.

3. It can prevent fire accidents caused by electric leakage.

3. Dual power automatic transfer switch:

The concept of dual power automatic transfer switch:

The dual-power automatic transfer switch is an automatic switching system between two power sources. When 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 The circuit supplies power to the load.

It is suitable for continuous power conversion of any two power sources such as UPS-UPS, UPS-generator, UPS-mains, and mains-mains.