| 摘要 |
619,437. Control of D.C. motors. GRAY, W. T., FERGUSON, A. D., and METROPOLITAN-VICKERS ELECTRICAL CO., Ltd. Dec. 10, 1946, No. 36457. [Class 38 (iii)] A control system comprises at least four motors and associated starting resistances with arrangements providing series, series-parallel and parallel motor combinations, in which both the transition between series and series-parallel and the transition between series-parallel and parallel are effected by bridge methods, said arrangements including switching means conconnecting the two outer motors of the series connection in one branch of the series-parallel connection and the two inner motors of the series connection in the other branch of the series-parallel connection, and providing a transition bridge connection by the connection of two starting resistances in parallel with said outer motors respectively and the connection of the other two starting resistances in series with one another in parallel with the other two series-connected motors. Initially, a master controller is actuated to close switches LS1, JR1, P3, J1, P4, JR2 and M3, to connect motor-armatures A1-A4 in series across the supply-lines with resistors R1-R4 in circuit. The series resistance is then gradually removed. In proceeding to a multiple series connection of the motors, a first transition stage is provided by closure of switches J2 and J3, to connect the four armatures in series directly across the supply-source. Thereafter, switches JR1, JR2, P3, P4 and RC1-RC4 are opened. Switches LS2, M4 and SP are then closed, and the switches P3 and P4 are reclosed, to provide the connection shown in Fig. 3, and upon opening of switches J2 and J3 the motors are connected in two parallel branches, each branch comprising two armatures and two resistors connected in series. Thereafter the resistors are gradually short-circuited. In proceeding to a parallel connection of the motors, a first transition stage is provided by closure of the switches LS4 and M2, to connect armatures A2 and A3 directly to the appropriate supply-lines, and closure of switch J4, to connect directly armatures A1 and A4. Thereafter switches LS2, P3, P4, M4 and SP are re-opened. Switches LS3 and M1 are then closed to provide the bridge connection of the armatures A1 and A4, with switch J4 in the diagonal connection, shown in Fig. 4. Switches LS2, P1, P2 and M4 are also closed to afford the similar bridge connection of the armatures A2 and A3, with the switch J1 in the diagonal connection, shown in that Figure. Opening of switches J1 and J4 provides a parallel connection of the motors. Closure of switches X1 and X2 affords the connection shown in Fig. 5, whereby a greater range of control is provided by the parallel connection of the pairs of resistors. |
