Automatic start control circuit informed by long power outage and incoming call

The circuit for the motor to automatically restart after a long power outage is shown in Figure 4-37. During normal starting, the switch SA on the platform, the power supply passes through
the moving contact of the intermediate relay KA, so that the energization delay time relay KT is electrically closed.
After delay, its delayed closing moving contact closes, causing the contactor to close.
KM gets electrical pull-in, its main contact closes, starts the motor, its auxiliary contact
closes and self-locks, and the other auxiliary contact closes, so that KA gets electrical pull-in.
The dynamic breaking contact of KA is disconnected, causing KT to lose power and release, cutting off the time relay
.
    If a power outage occurs while the motor is running, the KM will be released due to loss of power,
its main contacts will be disconnected, the motor will stop, and its auxiliary contacts will also be disconnected. When KA
loses power and is released, its moving contact is reset and closed, that is, the entire circuit except SA
returns to its original static state.
    No matter how long the power outage lasts, as long as the next call comes, the time relay
KT will get the electric suction table. After a delay, its delay contact will close, causing the KM to get the electric suction and self-locking, and the motor will start running. Obviously,
after another call, the motor will start automatically as a normal start.