METHOD FOR MONITORING OF INSULATION OF SHEETS OF STATOR LAMINATED CORES IN MOTORS AND GENERATORS AND DEVICE FOR ITS REALIZATION Russian patent published in 2008 - IPC G01R31/34 

FIELD: monitoring of motors and generators.

SUBSTANCE: an annular alternating magnetic flux with a low level of induction is produced in the core under check with the aid of a magnetizing coil. Scanning of the core recess surface is accomplished with the aid of an inductive pickup. The amplitude of the difference between the pickup signal and the references signal equal to the signal of the pickup installed in a defect-free point is measured, the conduction of the insulation is judged according to this measurement. The device has a magnetizing coil, pickup, adjustable power supply unit of the magnetizing coil, reference signal source and a control unit. The control unit has a device for adjustment of the reference signal in amplitude and phase, and a voltage measurement device. The reference signal source is connected to the input of the regulator device. The output of the regulator device is opposite-connected to the pickup output. The obtained difference signal is applied to the input of the voltage measurement device via a filter tuned to passage only of the output voltage frequency of the magnetizing coil supply source. The reference signal source may be built in the control unit.

EFFECT: enhanced accuracy of defect-shooting and determination of sensitivity at raised frequencies, simplified design.

4 cl, 5 dwg