Electric control circuit of voltage type is commonly used in protection

1, the loss of pressure loss of pressure protection: to prevent the power supply voltage disappears, when the voltage recovery motor self-starting protection from the dangers of starting: 1) Cause personal injury, equipment accident. 2) More than one motor self-starting of power grid is not allowed to over current and voltage drop. Loss of pressure protection device: buttons and contactor ( Since the lock) 2, low voltage protection, under voltage protection: supply voltage down to ( 0. 6 a 0. 8UN) When cut off power supply. Under voltage protection: to prevent the grid voltage lower electric release, cause abnormal circuit for protection. Under voltage protection: button and contactor ( Since the lock) , voltage relay. And the voltage of voltage relay setting: 0. 8 a 0. 85 urt release voltage of voltage relay setting: 0. 5 a 0. 7轨道交通。 3, overvoltage protection against overvoltage protection: discharge loop over voltage relay for inductive load