| 摘要 |
<p>PURPOSE:To convert an operation mode without altering the open or close of a main circuit switch and the exciting direction of a field by setting a chopper having a conductivity in a reverse direction exclusively for a brake and a power drive in parallel or in series with an armature. CONSTITUTION:When a power drive is instructed, a chopper FCH for field control and a chopper CH2 operating as an armature chopper start chopping. When a driver instructs a brake, the chopper CH2 is turned OFF, the chopper FCH extends its conduction width to increase currents flowing to fields F1, F2. As a result, an armature current is regenerated at a trolley wire through a diode for providing the reverse conductivity of the chopper CH2. An armature voltage drops as the speed of an electric rolling stock is decelerated so that the armature current tends to decrease, a chopper CH1 connected in parallel with armatures M1, M2 operates chopping to maintain the armature current in constant.</p> |
