Earth leakage circuit-breaker, referred to as “leakage switch, also called leakage circuit breakers, leakage failure is mainly used in equipment as well as to a potentially lethal person get an electric shock protection, overload and short circuit protection function, can be used to protect lines or motor overload and short circuit, can be in normal circumstances for the use of line not frequent conversion start.
Over and under voltage protector: also known as the double over and under voltage protector, meaning when the line over voltage and under voltage exceeds the specified value can automatically disconnect, and can automatically detect the line voltage, when the line voltage to normal can automatically close the device.
Mainly used for household and shopping malls distribution (single-phase AC230V, three-phase four-wire AC415V) lines as over voltage, under voltage, phase break, zero break line protection.
The connection and difference between leakage protector, air switch and over-voltage protector:
A, leakage protector according to its protection function and use classification is described, generally can be divided into leakage protection relay, leakage protection switch and leakage protection socket three.
- 1. Leakage protection relay refers to a leakage protection device that has the function of detecting and judging leakage current, but does not have the function of cutting off and switching on the main circuit.
- 2, leakage protection switch refers to not only it can be connected or disconnected with other circuit breakers, but also has the function of leakage current detection and judgment. When leakage or insulation damage occurs in the main circuit, leakage protection switch can be connected or disconnected according to the judgment results of the main circuit
- 3, leakage protection socket refers to the leakage current detection and judgment and can cut off the circuit of the power socket. Its rated current is generally below 20A, leakage action current is 6 ~ 30mA, high sensitivity, often used for the protection of handheld power tools and mobile electrical equipment and homes, schools and other civil places.
Second, air switch is a very important electrical appliance in low-voltage distribution network and electric power drag system, which integrates control and a variety of protection functions. In addition to complete the contact and break circuit, can also be circuit or electrical equipment short circuit, serious overload and under-voltage protection, but also can be used to infrequently start the motor.
Leakage protector cannot replace air switch. Although the leakage protector is more than the air switch a protection function, but in the process of operation because of the possibility of leakage often exist and will often trip phenomenon, resulting in load will often appear power outage, affecting the continuous and normal operation of electrical equipment.
Therefore, generally only in the construction site temporary electricity or industrial and civil building socket loop used.
Three, for overvoltage and undervoltage protection device, many people think that the probability of normal power grid zero overvoltage is much, in order to a N years can not happen can not a overvoltage, at most set an overvoltage trip can, is it necessary to “self-recovery”?
Generally speaking, the protection device can quickly and safely cut off the circuit under the continuous high voltage impact, so as to avoid the occurrence of accidents caused by abnormal voltage into the terminal electrical appliances. When the voltage returns to normal value, the protector will automatically switch on the circuit within the specified time to ensure the normal operation of the terminal electrical appliances in unattended circumstances.
Leakage protector, air switch and over-voltage and under-voltage protection device, each has its own characteristics, and different occasions also need to choose different devices, you can choose to install according to their own needs.