Three-phase motor overcurrent protection circuit

It is a three-phase motor overcurrent
protection circuit .
    Working principle: This circuit uses a transformer to induce
current when the current of the three-phase motor exceeds the normal operating current
. The overcurrent relay Kl reaches the set value of the pickup current and is closed
. Its normally closed contact is disconnected, and KM is released when it loses power, causing the main circuit
to lose power, thus protecting the motor and making it disconnect from the power supply when overcurrent occurs
.
    When the motor starts, the current is relatively large. Use
the normally closed contact of the time relay to short-circuit the current transformer first to prevent the motor starting
current from flowing through Kl and causing malfunction. After the motor is started
, the current drops to normal, and the time relay KT acts after a delay
. Its normally closed contact is opened, its normally open contact is closed, and KI is connected to the
current transformer line.