GB439320A - Improvements in or relating to electric motor controllers - Google Patents

Abstract

439,320. Master control of D.C. motors; actuating controllers. WEST & CO., Ltd., A., and PADDOCK, W. J., Lewes Road, Brighton, Sussex. Sept. 3, 1934, No. 25299. [Class 38 (iii)] Armature and field control ; rectilinear sliders; combination of resistances.-A motor is accelerated by removing. series accelerating resistance from circuit, and further accelerated by connecting the accelerating resistance in shunt with the motor series field winding and again removing it from circuit, an additional shunting resistance being provided which is out of circuit during the first accelerating stage, but is connected in series with the accelerating resistance when the latter is in shunt with the field, so that when the accelerating resistance is removed from the shunting circuit, the additional shunting resistance remains in shunt with the field. Upon operation of sliding contact members 11 from the end A to the end B of their respective resistance 3 and 4, the resistance is gradually removed from the armature circuits of the respective motors 1 and 2. Switches 18, 19 are then closed and the switch 20 opened so that the motor armatures are connected in parallel each with its own accelerating resistance in series. The contacts 11 are then returned to the ends A thereby again removing the series resistances in steps. Switches 21-24 are then closed so that the series fields 5, 6 of the parallel-connected motors are shunted each by its own resistance 3, 4, additional shunting resistances 7, 8 being included in the respective shunting circuits. Upon returning the contacts 11 to the ends B of the resistances, the resistances 3, 4 in the shunting circuits are again removed leaving only the resistances 7, 8 in circuit. The contacts 11 are operated by an electric or pneumatic motor under the control of a master controller which also controls the motor circuit connections. When an electric pilot motor is provided, a main motor current relay is effective to short-circuit the armature of the pilot motor when the current attains a predetermined value, thereby arresting the movement of the contacts 11. The pilot motor may be arranged to return the contacts to the starting position when the master controller is moved to the " off " position.