| 摘要 |
PURPOSE:To eliminate an influence of a resistance, due to variation in control power voltage and the kind and length of a transmission line, on the state of an equipment of a supervised part by forming a supervisory part of a transistor, Zener diode, etc. CONSTITUTION:While a blower is in a positive rotation state, contact S1 is ON to flow a current from positive-pole power bus P1 to the base of transistor TrQ1 via transmission line L, and consequently TrQ1 turns ON to drive state detection relay 6. At this time, Zener diode ZD1 is never put into operation, so that TrQ2 will not turn ON. Next, when the blower changes to a reverse rotation state, contact S2 is made to flow a current to the base of TrQ2 via Zener diode ZD1, thereby driving state detection relay 7. At this time, the current of the base of TrQ1 is cut off by diode D4 and TrQ1 is turned OFF, so that relay 6 will not operate. On the other hand, when the blower is a stationary state, contacts S1 and S2 are both OFF and Trs Q1 and Q2 are both OFF, too. |
