Three-phase asynchronous motor sequence control circuit

In production, multiple motors are often required to work together. According to the requirements of the process flow, their starting and stopping must
be carried out in a predetermined order. For example, some large machine tools require that the spindle must be able to work with coolant. Therefore, the oil pump
motor must be started to provide coolant to the spindle, and then the spindle motor can be started. In the same way, the spindle motor must be stopped first when parking. , and then
the oil pump motor can be stopped. When the coil is electrified, the moving contact is closed and the moving contact is open.
    (1) Circuit composition The sequential starting control circuit is shown in Figure 4-3. In the figure, contactor KM1 controls the oil pump motor Ml, and contactor
KM2 controls the spindle motor M2. The control circuit part of the oil pump motor is a typical starting and stopping control circuit, and
the auxiliary moving and closing contact KM1 of the contactor KM1 is added to the spindle motor control circuit. Therefore, only the contactor KM1 acts, the oil pump motor starts,
and the contact KM1 Closed, the contactor KM2 that controls the spindle motor M2 can be turned on.
    This control effect is called "interlocking", and the KM1 contacts are called "interlocking" contacts.
    (2) Sequential starting control is connected according to circle 4-3, in which the three-phase
  AC power supply is 380v, and the motors all adopt Y connection method. Turn off the knife switch os, operate the
  start button SB2, the KM1 coil is energized, the KM1 main
  contact connected in the main circuit is connected to the three-phase power supply, and the motor M1 runs; the KM1 auxiliary contact connected in series in the KM2 control
  circuit Turn it on, press SB4, the KM2 coil is energized,
  the KM2 main contact connected in the main circuit is connected to the three-phase power supply, and the spindle motor
  M2 runs.
    (3) Sequential stop control Sequential stop control adds an "interlock" link to the above control circuit
  . The auxiliary moving contact KM2 of the contactor KM2 is connected in parallel with the stop button SB1 of the oil pump motor. In this way,   the stop button SB3
  is connected.
, the spindle motor M2 is powered off and stops. Only after the spindle
  motor IVI2 stops, the moving contact KM2 in parallel with SB1 is disconnected, and then
  the stop button SB1 can be used to stop the oil pump motor, so that the spindle motor M2 must be stopped first , and then the oil pump motor   Ml
  can be stopped sequentially. control.