| 摘要 |
Control circuit for a traction vehicle propulsion system which system comprises a d-c motor (2) and an excitation generator (3) for separately exciting the motor field (2b). Current in the field winding (3b) of the excitation generator is normally controlled by the control circuit (15) which is arranged to prevent vehicle misdirection due to control circuit failure modes wherein normal excitation current is not supplied. The control circuit comprises means (50,50b,50c) responsive to an acceleration command signal for temporarily removing the field winding from the normally operational control circuit configuration (41, 44) and for placing it instead in a biasing circuit comprising low impedance paths (52,54c;51,60) to the respective terminals (B+,G) of a direct voltage source, thereby presetting the magnetic field of the field winding in the proper direction to prevent vehicle misdirection upon acceleration from rest. |
