METHOD FOR IN-SERIES INSPECTION OF HEATING AND PROTECTION OF ELECTRIC MOTORS Russian patent published in 2011 - IPC H02K15/00 G01R31/34 

FIELD: electricity.

SUBSTANCE: when implementing the proposed method, temperature sensor is placed into hollow threaded bolt which is screwed into the seat of eye-bolt of electric motor housing; at that, contact points of hollow metal bolt with housing of electric motor and temperature sensor are coated with heat-conducting paste; heating temperature of stator core is measured; the value of obtained signal is amplified; at that, quantitative connection between heating temperatures of core and winding is considered by determining the value of temperature coefficient K_t=T_w/T_s, where T_w - winding temperature, T_s - stator temperature, and obtained value of stator temperature signal is increased by 1.4 - 1.7 times; actual value of heating temperature signal of stator winding is obtained and supplied to input of signal unit; the obtained signal is compared to signal of setting device by means of which the required threshold of actuation of signal unit is set, which considers the value of maximum allowable overheat temperature of winding of protected electric motor for this insulation class, the required temperature reserve is created; indicator-light emitting diode is connected to the first output of signal unit; acoustic wave generator-buzzer is connected to the other output of signal unit; and the third output of signal unit is connected to tripping device, and by means of them, in case of emergency situation due to overheat of windings of protected electric motor the light signal is supplied and at the specified time interval the acoustic signal is supplied, which indicate emergency situation occurrence, or the signal for cut-off of protected electric motor with magnetic starter is supplied from supply mains.

EFFECT: simplifying the method, improving heating control accuracy of electric motors and protection reliability of windings of electric motors against overheat in operating conditions; method provides the possibility of independent use and excluding the interference with the design of electric motor for installation or replacement of failed temperature sensors built in front parts of stator windings of electric motor.

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