| 摘要 |
PURPOSE:To obtain a rectifying compensator for a DC machine where nothing abnormal happens in a flashover accident, by shorting between terminals of an auxiliary winding when the terminal voltage of the auxiliary winding exceeds a command value. CONSTITUTION:The armature current IL flows to a commutating pole winding 8 through a brush 11 and a commutator 12. On the other hand, the current IL of an auxiliary winding 10 from a current detector 13 and the output of the rotational frequency detector 14 are inputted into a multiplier 15 to get a current command Ip*. A comparator 26 compares the current command Ip* with the output of an auxiliary winding current detector 28 and gives a current control signal VA to a gate signal generation circuit 16. A drive circuit 24 turns ON a power transistor T5 when the induced voltage Ea of the auxiliary winding 10 becomes larger than the command value, and it shorts the auxiliary winding 10. Thus, in case the high voltage is generated to the auxiliary winding in flashover accident of a DC machine, the destruction of a condenser 23 by overvoltage can be avoided. |
