| 摘要 |
A wheel slip control system for electric traction motor drives employing series-type direct current traction motors having field and armature windings connected in series electrical circuit relationship, a power rectifier and a source of alternating current supplying the power rectifier. The series-type traction motors are connected across the output from the power rectifier for the supply of normal excitation direct current. The improvement comprises a current transformer having primary and secondary windings wound on a common core. The primary winding is serially connected in the supply connection between the alternating current power source and the power rectifier. The secondary rectifier is provided with its output connected to supply auxiliary field current to the field winding of each series-type direct current traction motor in addition to the normal direct current excitation supplied through the power rectifier. The polarity of the auxiliary field current is such that upon addition to the normal excitation direct current, the field current is maintained substantially constant or slightly less so from what it had been prior to a wheel slippage condition, and a detector is provided for detecting a wheel slippage condition and controlling supply of the output current from the secondary winding of the current transformer to the secondary rectifier for enabling the supply of auxiliary field current to the field winding of the series-type direct current traction motor that was slipping. |
