Self-locking, the phenomenon of relying on a contactor's own auxiliary contacts to keep its coil energized.
Interlocking, said to be between several circuits, the use of the auxiliary contacts of one circuit, to control each other's coil circuits, state maintenance or function limitation. The general object is the control of other circuits.
Interlocking, that is, the set conditions are not met, or internal and external triggering conditions caused by changes in the associated electrical, process control equipment, the working state of the control mode change.
Expanded information:
Self-locking interlocking protection:
1, under voltage Protection: When the power supply voltage drops for some reason, the motor torque will be significantly reduced, affecting the normal operation of the motor, the seriousness of the phenomenon will cause a "blocking" phenomenon, so as to damage the motor. The use of contactor self-locking control circuit can avoid the above failure.
Because when the supply voltage is lower than 85% of the rated voltage of the contactor coil, the electromagnetic force generated by the electromagnetic system of the contactor can not overcome the reaction force of the spring, and thus released, the main contact opens, automatically cut off the main circuit to achieve the role of undervoltage protection.
2. Loss-of-voltage protection: when the motor is started, if the power supply circuit stops, but then the power supply is restored, in this case, due to the self-locking contacts are still open, the motor will not be started by itself, and it must be re-commanded (press the start button SB2) in order to start.
Baidu Encyclopedia - Self-locking Interlocking
Baidu Encyclopedia - Self-Locking