METHOD OF PROTECTING THE ELECTRIC ENGINE FROM TECHNOLOGICAL OVERLOADS AND DEVICE FOR ITS IMPLEMENTATION Russian patent published in 2017 - IPC H02H7/85 H02H5/04 

FIELD: electricity.

SUBSTANCE: motor current is fixed. Converting it to a value and turning the engine off. For the criterion of a dangerous regime, the instantaneous value of the heating temperature is taken regardless of the shape of the current. The instantaneous value of the overload current passing through the motor and the instantaneous value of the voltage on the motor are fixed. They are multiplied by a quantity proportional to the resultant multiplication of power dissipated in the engine and heating it. It is submitted to the elements that recreate the exponential dependencies, corresponding to the heating curves of different conventional sections of the structure of the protected motor. The parameters of the elements are obtained by decomposing the experimental curve of the heating of the most dangerous part of the thermal structure of the protected motor to its constituent exponents. And the parameters at the output of these elements add up, obtaining a parameter proportional to the instantaneous temperature of the overheating of the most dangerous part of the physical structure of the engine relative to the environment, which is added with the value of the parameter proportional to the ambient temperature. The resulting value, which is proportional to the instantaneous value of the heating temperature of the most dangerous part of the physical structure of the motor, is compared with the setpoint temperature of the protection trip. The result of the comparison is converted into the corresponding electrical signals, by means of which a protective shutdown of the motor is made. The overload protection device of the motor consists of a current sensor (1), an engine (6) connected to a transducer (3), which converts the power dissipated in the engine (6) into an amount proportional to the instantaneous temperature of the dangerous section of the structure of the protected engine (6). The voltage sensor on the motor (2) is also connected to the input of the inverter (3). Converter output (3) is connected through contacts (4) to the contactor (5), intended for protective shut-down of the engine (6).

EFFECT: increasing the accuracy threshold of protection.

2 cl, 2 dwg