| 摘要 |
1,225,919. Control of D.C. motors. HITACHI Ltd. 8 Aug., 1969 [9 Aug., 1968], No. 39915/69. Heading H2J. [Also in Division G3] In a traction system comprising motors M1, M2, the movement of a master controller 55 to a first position closes contactors 33, 37, and movement to a second position closes contactor 27 whereby armatures 15, 21, are connected in series with resistors R11-R13 and R21-R23. When the armature current decreases to a set value, a comparator 81 opens gate 113 and a signal is applied to device 89 to advance camshaft controller 69 to notch S2. Resistorsection R11 is short-circuited, the armature current being increased, and then decreased as the vehicle accelerates. A segment on the camshaft controller provides a signal for maintaining movement between notches, whereby the controller successively advances under the control of comparator 81 to remove resistor-sections from the armature circuit up to the fifth notch. Between notches S1-S5, a signal for selecting full field is applied to proportional controller 71, gates 115, 117 producing no output and gates 119, 75, being opened. Comparator 85 is associated with field current detector 43 so that chopper controller 87 operates to maintain full field. When the notch S5 is reached, the armature current decreases and a constant torque controller 73 is associated with an armature current detector 41 to regulate the chopper-35. When the armature current reaches a value corresponding to minimum field excitation, comparator 83 responds to close gate 77 and the controller 71 is connected to comparator 85. The traction motors are immediately brought into the full-field condition. The cam-shaft controller is then advanced to notch S7 where it is halted, removal of armature resistance being followed by field-weakening as before. If the master controller 55 is moved to its third position, the field excitation of the motors is increased and the cam-shaft controller 96 is advanced to notch P1 wherein the motors are connected in parallel. Field weakening is effected when the armature current decreases, the cam-shaft controller moving forward to notches P2 and P3. Resistors R14, R24 and R15, R25, are short-circuited simultaneously so that the armature currents of the motors M1, M2, are kept equal. If the master controller 55 is moved to its fourth position, comparator 79 responds to close gate 77 and open gate 75, a field-weakening signal being applied to controller 71. The armature voltage in the weakest field condition may be higher than that in the full field condition at the next notch. During dynamic braking operation, the traction motors function as differential compound generators, constant torque regulation being provided. |
