| 摘要 |
PURPOSE:To effectively protect a motor against overload by sampling the current and the temperature rise of the motor at a predetermined period of time and estimating the current and the temperature rise in the next period. CONSTITUTION:A protecting device 1 samples the load current of an induction motor 1 and the stator temperature detected respectively by a current transformer 5 and a temperature detector 10 to obtain varied current and temperature amounts and to estimate the current and the temperature in the next period based on the obtained varied amounts. Then, a main breaker 4 is interrupted in response to the estimated current value and temperature value. Thus, the motor can be effectively protected against the overload. |
