| 摘要 |
PURPOSE:To improve the detecting accuracy by employing two different commutation spark detecting methods and producing an output signal only when detection signals are obtained simultaneously by the both methods, thereby eliminating the adverse influence due to improper sliding of a brush. CONSTITUTION:Two different commutation spark detecting methods are employed, and the detection signals of the both methods are input to a comparator 16. The comparator 16 produces an output signal Vb' only when the both detection signals exist simultaneously, and delivers the output to an indicator or a display unit after passing a waveform processor 17. The two different methods may employ, for example, a combination of an armature voltage type spark detecting method and a spark light type detecting method, or a combination of an armature voltage type spark detecting method and a brush vibration detecting method. |
