| 摘要 |
<p>This invention relates to a series excitation motor speed control cicrcuit that can choose the operation of alternating current double-speed motors between high speed operation and limited speed operation. The improved circuit is characterised by the use of switch SW1 to control the positive bias diode assembly which is connected in parallel to the two ends of series-excitation armature so as to produce series-excitation free operation of motor assembly, switch SW1 can also be connected to armature in parallel to control the operation speed by armature negative potential. The above mentioned positive bias diode assembly can further be connected to current limiter element in series. <IMAGE></p> |
