Single three-phase asynchronous motor time control circuit

In production, many processing and control processes are controlled based on time, such as workpiece heating time control, motor starting
and stopping control in time sequence, motor Y-△ starting control, etc. These types of controls all use time relays. to achieve.
    (1) Time relay The time relay is a delayed action relay. It
has a certain time interval from receiving a signal (such as a coil being charged) to executing an action (such as contact opening or closing). This time interval can be preset as needed. Tuning to coordinate and control various
actions of production machinery. The types of time relays usually include electromagnetic type, electric type, air type and electronic type.
The contact system of the time relay has delayed action contacts and instantaneous action contacts, among which there are closing
contacts and breaking contacts. Delay action contacts are divided into power-on delay type and power-off delay type. ．
    (2)-Single motor time control circuit The circuit that controls the running time after the motor starts.
As shown in Figure 4-8, press the start button SB2, the contactor KM is energized and self-locked, and the motor starts
and runs. At the same time, the time relay KT is energized and starts timing. When the preset
time is reached, its delay breaking contact KT is disconnected, the contactor control circuit is cut off , and the motor
stops. Similarly, the delay moving and closing contacts of the time relay can be used to connect the contactor control circuit
to achieve time control.
    The time relay delay time can be adjusted as needed. If it is set to 5s, check that the wiring
is correct and then turn on the main power supply. Start the motor and observe
the action of the AC contactor, time relay and motor ; the delay time of the coup time relay is 10s, repeat the above operation.