What is the voltage-less protection?

Due to short-circuit fault and other reasons, the line voltage will appear in a short period of time to reduce or even disappear phenomenon. It can cause damage to lines and electrical equipment. For example: The motor tired down, plugging, resulting in a number of times the rated current over the current, burning the motor; When the voltage is restored, a large number of motor starting will cause the motor voltage drop greatly, causing harm.

The voltage that causes the motor to be exhausted is called the critical voltage. When the line voltage is reduced to the critical voltage, the action of protecting the electrical apparatus is called the Undervoltage protection, whose main task is to prevent the equipment from being burnt down due to overload. When the voltage of this circuit is lower than the critical voltage protector, the action is called Loss voltage protection, its main task is to prevent the motor from starting.