| 摘要 |
PURPOSE:To prevent reverse rotation of an engine, by producing pulse signals the time ratio of which at the time of normal rotation of the engine is different from that at the time of reverse rotation of the engine, controlling charging and discharging of a capacitor, and detecting the voltage of said capacitor. CONSTITUTION:Since variation of the magnetic flux at the time when a rotor 19 of a ringer 1 is turned in normal direction is different from that when the rotor 19 is turned in reverse direction, a wave form having a different time ratio of a high level and a low level can be obtained. When the level of the shaped output is L, current is passed through a transistor A308, so that a capacitor 312 is charged. On the other hand, when the output of a wave-form shaping circuit 2 is inverted and its level becomes H, current is passed through a transistor 310, so that charge of the capacitor 312 is discharged. Thus, since the charging period of the capacitor 312 is longer than the discharging period at the time of reverse rotation, the charging voltage of the capacitor 312 is increased gradually. When the charging voltage is raised to a trigger level, an engine stopping means 5 is set into operation to prevent reverse rotation of the engine. |
