| 摘要 |
PURPOSE:To improve the accuracy of preventing over speed of an engine by controlling the engine while obtaining a constant electric charge on every period of the rotation signal of a signal coil and comparing the time determined by the time constant with the period of the rotation signal of the signal coil at the time of the charging and discharging, the output of the above-said electricity. CONSTITUTION:A condenser 27 which charges or discharges a constant electric charge one for every period of a signal coil 5 and a condenser 29 which receives the constant electric charge from this condenser 27 and charges or discharges it, are provided in an over-speed preventing circuit 20. A transistor 35 is connected or intercepted by a terminal voltage of a condenser 32 charged in response to connection of a transistor 30 which is connected or intercepted after detecting the terminal voltage of the above-said condenser 29, and a thyristor 38 is controlled for preventing the over speed of an engine. This construction permits to eliminate the variation of the set number of revolutions for preventing the over speed with a high accuracy even if the output of the signal coil 5 makes variation because of the dispersive characteristic of the signal coil 5 or a change of the thermal characteristic. |
