air compressor circuit

Air compressor control circuit , the principle analysis of this circuit is as follows:
    (1) Overload protection function of thermal relay FR. When the motor is overloaded for a long time, the thermal relay. FR action, it helps the ship's bow to disconnect and
protects the compressor from overheating and damage.
  l; (2) Circuit breaker-QF protection function. When a short-circuit fault occurs in the main circuit of the air compressor, the circuit breaker will ride on the over-current tripper.
When the motor is overloaded and protected, the circuit breaker will open. The thermal tripper of the compressor will cut off the overloaded compressor. ,
    (3) The cutoff protection function of the medium-sized insulator KA is static. The KA and KM coils are connected to three circuits respectively . When any phase of the two-phase power supply connected to the KA coil
is disconnected, the KA pin cannot be closed. The KA normal contact is disconnected and the KM coil loses power {when any one of the two phases connected to the KM coil is disconnected
. The KM coil cannot be actuated and the motor stops running. ;．
    (4 ) Protection function of press electrical appliances When there is no pressure in the compressor, its normal contact point SP is in the connected state. At this time, when the start
button SB2 is connected, KM is closed, and the compressor is running. When the compression When there is a certain pressure in the machine, press the stop button SB1 and the compressor will stop.
    When the pressure inside the compressor exceeds the allowable value, its purple-closed contact SP is disconnected, cutting off the AC contactor power supply and shutting down.