| 摘要 |
<p>PURPOSE:To facilitate for switching high and low speed operation, changing command current by open/close of change-over switch causing the load current limiting value to make small. CONSTITUTION:A signal A corresponding to stepped on accelerator pedal is fed into the command winding 11 of magnet phase shifter 6 by means of transistor (TR6). A signal transmitted from power winding 8 of magnet phase shifter 6 is applied to thyristor chopper 3 by means of Miller integrator 15 and Schimitt circuit 14 to control speed of motor 1. With a change-over switch 12 turned on, since the accelerator power voltage is dropped by means of Zener diode ZD2, the impedance of TR6 becomes large to provide small command current, causing small load current limiting value. Further, in this case transistor TR8 becomes low impedance with the increase of current flowing rate of chopper, pulling accelerator power voltage until reaching a specified current flowing rate, and causing to suppress the revolutions of motor.</p> |
