DEVICE FOR THREE-PHASE ELECTRIC MOTOR PROTECTION Russian patent published in 2017 - IPC H02H7/08 

FIELD: electricity.

SUBSTANCE: device for protecting the three-phase electric motor contains an actuator connected to the output of the OR element, the first, second and third reed switches with control windings connected to the phase conductors of the corresponding phases on the side of the motor switch. The first, second and third elements MEMORY, connected to the contacts of the first, second and third reed switches, respectively. The fourth reed switch with the closing contacts with the first, second, third and fourth control windings, of which the first and second control windings are connected to the phase conductors of phases A and C on the breaker side, and the third and fourth control windings are connected to the phase conductors of phases A and C Side of the motor's zero leads. The first and second control windings are connected counter to the third and fourth control windings. The fourth reed switch through the fourth element MEMORY is connected to the OR element. The first, second, third MEMORY elements are respectively connected to the first, second, third NO elements that are connected to the OR element. The output of the actuator is connected to the motor switch.

EFFECT: expansion of functionality by detecting phase-to-phase faults and phase failure inside the motor.

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