| 摘要 |
PURPOSE:To stably drive an AC motor by controlling a DC voltage applied to an inverter form the frequency of a speed pulse, thereby limiting the output voltage when the motor is operated at a low speed. CONSTITUTION:When a speed pulse outputted from a pulse generator 5 is inputted to a phase distributor 6, the distributor 6 controls ON/OFF transistors 21, 24 and 22, 23 to alternately flow a current, thereby driving an AC motor. An F/V converter 8 controls a voltage regulator 7 to gradually increase the output produced between terminals t and t' when the speed pulse falls within the low speed range. Thus, the output current is maintained at the prescribed level in the low speed range. Thus, even when the motor is operated at the low speed, the output voltage generated between the terminals t and t' is limited to stably drive. |
