| 摘要 |
PURPOSE:To enable the optimum protective monitoring of the winding temperature of a motor to be executed, by comparing a computed current value and an actual current value with each other, and an estimated temperature rise value and an actual temperature rise value with each other, respectively, by discriminating whether the respective values are within proper ranges or not. CONSTITUTION:By a protective monitor 21, from the output torque and rotational frequency of a motor 11, output is found, and by the output and the terminal voltage of the motor, a current value is computed. Then, the computed current value and an actual current value are compared with each other and when the values are out of an error range, it is discriminated whether the actual temperature rise value of the motor 11 is within the allowable value of a motor winding or not. When the value is equal to or more than the allowable value, the motor 11 is stopped. When the value is equal to or less than the allowable value, a temperature rise value is computed based on the computed current value or the actual current value. Besides, when an estimated temperature rise value is equal to or more than the allowable temperature range of the motor 11 and the actual temperature rise value is equal to or more than the allowable value, then the motor 11 is stopped. |
