| 摘要 |
PURPOSE:To effectively protect the overload of a variable speed rotary electric machine in all rotating speed controlling range by detecting the load current at the sequentially rotating time, comparing it with an allowable load current value, and breaking a main circuit with the result. CONSTITUTION:The sequential rotating speed of a variable speed motor 4 is converted via a tachometer generator 8 into voltage or current, which is in turn fed to a function generator 9. The generator 9 outputs the allowable load current corresponding to the sequential load current of the motor 4. A comparator 10 compares the load current with the allowable load current from the generator 9 and a current transformer 6, and when the load current exceeds the allowable current, it produces an output to an output device 11. When the device 11 operates, a main circuit is interrupted. |
