DEVICE FOR THREE-PHASE ELECTRIC MOTOR PROTECTION AGAINST OPERATING EMERGENCY CONDITIONS Russian patent published in 2021 - IPC H02H7/08 

FIELD: electrical engineering.

SUBSTANCE: device contains a power supply unit made with three nodes. The first unit includes an input noise suppression filter, a line rectifier and a smoothing capacitor at the output. The second node for voltage stabilization and regulation contains a pulse-width modulation (PWM) controller with eight functional outputs, three capacitors, six resistors, a moving contact potentiometer, a thermistor, a field-effect transistor, two diodes and a primary winding of a pulse transformer. The third node contains a secondary low-voltage winding of a pulse transformer, a power diode and a filter capacitor. The executive body is made in the form of Peltier elements connected in series, fixed on the stator surface between the cooling fins of the induction motor using spacer wedges and a clamp by means of a tension screw twisted into the terminal box. The "cold" side of the Peltier elements is connected to the stator surface, and the "hot" side is connected to a clamp that acts as a cooler through spacer wedges.

EFFECT: increase in reliability of the protection device and the possibility of trouble-free operation of the electric drive in the process of overheating of the running engine.

1 cl, 4 dwg