| 摘要 |
PURPOSE:To realize accurate protection easily by measuring energy supply time to a protective object, operating the load of the protective object based on the measured time, comparing the operated load with a reference value and judging overload of the protective object thereby protecting the object against overload. CONSTITUTION:The overload protective system comprises a memory 19 for storing the load 15 of a motor 4, a backup memory 20, an element block 21 for subjecting the load 15, outputted from the memory 19, to operation with the time interval between interruption and throw-in of a control power supply as a parameter, and the like. Time interval after interruption before restart of energy supply to a protective object is then measured and the load of the protective object is operated based on thus measured time interval. Thus operated load is then compared with a reference value in order to judge overload of the object thus protecting the object against overload. |
