One-unit electric introduce: our distribution cabinet internal components

The distribution box is a mass parameter on the data, which is generally composed of low-voltage electrical wiring, requiring the switchgear, measuring instruments, protective appliances and auxiliary equipment to be assembled in a closed or semi-closed metal cabinet or screen to form a low-voltage distribution box. The circuit can be switched on or off by manual or automatic switch during normal operation.

Use of distribution box:

Reasonable distribution of electric energy, easy to open and close the circuit operation. It has a high level of safety protection and can visually display the on-state of the circuit.

Distribution box principle: According to the electrical wiring requirements, the switchgear, measuring instruments, protective appliances and auxiliary equipment are assembled in a closed or semi-closed metal cabinet or screen to form a low-voltage distribution box. The circuit can be switched on or off by manual or automatic switch during normal operation. In case of failure or abnormal operation, cut off the circuit or alarm with the help of protective appliances. The measuring instrument can display various parameters in operation, and can also adjust some electrical parameters to prompt or signal deviation from the normal working state.

The power distribution cabinet (box) consists of power distribution cabinet (box), lighting distribution cabinet (box) and metering cabinet (box), which are the final equipment of the distribution system. Distribution cabinet is the general name of the motor control center. The power distribution cabinet is used in the occasions where the load is relatively dispersed and the circuit is less; The motor control center is used for load concentration and many circuits. They distribute the electrical energy of a circuit of the upper level distribution equipment to the nearest load. This level of equipment should provide protection, monitoring and control of the load.

Power cabinet refers to the electrical control cabinet combination that provides power to the normal operation of the whole machine, including contactors, frequency converters, high voltage cabinets, transformers, and so on

Power cabinet function:

1. Power supply for electrical equipment (power supply for equipment);

2. Electric equipment for start-stop operation (with start-stop button);

3, the operation of the detection equipment (set the signal indicator light, ammeter voltmeter);

4, the protection of electrical equipment (circuit breaker) power cabinet is the power distribution cabinet, which is designed to provide power and control for power equipment (generally refers to the motor).

10kv high voltage cabinet and 400v low voltage cabinet (regardless of incoming line, outgoing line, metering, capacitance, liaison, voltage change, etc.) can be called the distribution cabinet.

The equipment below the 400v low pressure cabinet, which belongs to the secondary side outlet load is the power facility (such as fans, motors, pumps, etc.), then it is called the power cabinet. The load for lamps, switches, sockets such equipment is called the distribution box.

Distribution box: Small power distribution box containing power switches and safety devices.

Control box: A small control distribution box containing a power switch/safety device/relay (or contactor) that can be used for specified equipment control, such as motor control.

Power distribution cabinet: It is actually a large-scale distribution box, which can provide more power or more channels of power output.

Control cabinet: It is actually a large-scale control box, which can provide more power or more channels of control output, and can also achieve more complex control.

Control panel: Only the front control cabinet, all internal devices are installed on the panel.

The distribution box is mainly divided into two parts

The first is a complete set of parts, 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.

The cabinet consists of the following parts: Circuit breaker Circuit breaker: both switch, is the main component of the distribution cabinet, commonly used air switch. Leakage switch. Dual power automatic transfer switch

1. Air switch:

A. Concept of air switch:

The air switch is also the air circuit breaker, which is connected, broken and carries the rated working current and short circuit, overload and other fault currents in the circuit, and can quickly break the circuit in the case of overload, short circuit, undervoltage and so on, for reliable protection. The design types of dynamic and static contacts and contact rods of circuit breakers are various, but the main purpose is to improve the breaking capacity of circuit breakers. At present, the current limiting principle, which limits the peak value of short circuit current when breaking by using certain contact structure, has obvious effect on improving the breaking capacity of circuit breakers, and is widely used.

B. The working principle of the air switch:

Automatic air switches, also known as low-voltage circuit breakers, can be used to switch on and off the load circuit, and can also be used to control the motor that does not start frequently. Its function is equivalent to the knife switch, overcurrent relay, voltage loss relay, thermal relay and leakage protector part or all of the function of the sum of the low voltage distribution network is an important protection electrical appliances.

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

2. Leakage protection switch: A. Leakage protection switch concept:

It has the function of leakage protection, people touch the electrification will trip, to ensure personal safety, is the main function of leakage protector; If the insulation of the electrical equipment is not good enough to leak to the shell, the leakage protector will also trip to avoid human touch shock. At the same time, it has the function of current break, overload protection and short circuit protection.

B. Working principle of leakage protection switch:

Working principle diagram of leakage protector. LH is a zero-sequence current transformer, which is composed of an iron core made of permalloy and a secondary coil wound on a ring iron core. The phase line and neutral line of the power supply pass through the round hole to become the primary coil of the zero-sequence transformer. The rear outlet of the transformer is the protection range.

C. The role of the leakage protection switch :1, when the electrical equipment or line leakage or grounding fault, can be cut off before the person has not touched the power supply. 2, when the human body touches the charged object, it can cut off the power supply within 011s, thereby reducing the damage of the current to the human body. 3, can prevent fire accidents caused by 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 for two power supplies. When the first power supply fails, the dual power automatic transfer switch automatically switches to the second power supply to the load. If the second power supply fails, the dual power automatic transfer switch automatically switches to the first power supply to the load.

Suitable for UPS-UPS, UPS- generator, UPS- mains, mains - mains and so on any two power supply constant power conversion.

2. Surge protector:

A. Concept of surge protector:

A surge protector, also known as a lightning arrester, is an electronic device that provides safety protection for various electronic equipment, instruments, and communication lines. When the electrical circuit or communication line suddenly produces a peak current or voltage due to external interference, the surge protector can switch on the shunt in a very short time, so as to avoid the damage of the surge to other equipment in the circuit.

B. Basic knowledge of surge:

The main role of the surge protector system is to protect electronic equipment from "surge" damage. So if you want to know what a surge protector does, you need to figure out two things:

What is a surge? Why do electronic devices need their protection?

A surge, also called a surge, is, as the name suggests, a transient overvoltage that exceeds the normal operating voltage. Essentially, a surge is a violent pulse that occurs in just a few millionths of a second. Possible causes of surges include heavy equipment, short circuits, power switches, or large engines.

A surge or transient voltage is a voltage that substantially exceeds its rated level during the flow of electrical energy.

In the United States, the standard voltage for wiring in the average home and office environment is 120 volts. Problems can occur if the voltage exceeds 120 volts, and surge protectors help prevent the problem from damaging the computer.

C. The role of the surge protector: