| 摘要 |
<p>PURPOSE:To prevent the temperature rise of a snubber resistor by measuring a constant-speed operation time in each pulse mode and by stopping an inverter action after the lapse of a fixed period of time. CONSTITUTION:When a master controller 6 is inputted in a constant-speed operating position, changeover switches 9 and 10 are changed over to the make and break position opposite to that shown in the drawing. Also, if a constant- speed command is given to a target speed setter 20, a vehicle speed signal fr is latched and speed command signal fp is set. On the other hand, the constant-speed command is also given to a constant-speed counter 22. The constant-speed counter 22 starts counting when the pulse mode determined by a PWM modulator 15 is that other than 1 pulse, outputs a constant-speed ineffective command 27 after the lapse of fixed period of time, and gives an inverter stop signal to inverter 2. Thus, it is possible to prevent the temperature rise of a snubber resistor generated at a constant-speed operation in other pulse modes other than 1 pulse mode.</p> |
