| 摘要 |
PURPOSE:To enable to maintain a necessary brake force to a low speed by controlling so that a motor current becomes constant at an electric brake time. CONSTITUTION:A reverse unit RV is eonverted in a reverse direction to a power drive time at an electric brake time, and a counterelectromotive force is added to the output of a thyristor converter. On the other hand, a switch P is opened to connect a brake resistor R in series with a motor armature. When the speed is V0 or highre, the output ES of a thyristor converter becomes ''0'', and a field current IF is controlled so that the motor current IM becomes constant. When the speed decreases so that the current IF reaches the maximum value, the converter operates to maintain the voltage ER of the resistor R constant, thereby compensating the amount reduced by the motor voltage EM to control the motor current IM constant. |
