Patent GB-191084-A (GB)
Abstract: 191,084. Entz, J. B. Nov. 5, 1920, [Convention date] Dynamos and motors combined for transmitting power; electromechanical power transmission. - An electromechanical power transmission system, comprising a dynamo-electric machine one element of which is connected to the driving shaft and the other element to the driven shaft, a record dynamoelectric machine having a fixed field and its armature connected to the driven shaft, and a battery, is provided with a controller for varying the circuits of the machines to permit the element connected to the prime mover, to vary the speed of the driven shaft, and to control the starting of the prime-mover. The second dynamo-electric machine is provided with a series field winding and a winding connected across its armature or across the armature of a supplementary machine driven by the prime-mover or driven shaft. In the first speed position of the controller, the development of which is shown in Fig. 1, the armature 1 of the first machine, connected to the driven shaft, the field winding 2 of this machine, connected to the driving shaft, the fixed field winding 7 of the second machine and the armature 8 of this machine, connected to the driven shaft, are connected in series, the field-winding 2 being shunted by a resistance 10 and the excitation current being supplied by a battery 6 through resistances 4 and 5. In the second position of the controller a resistance 9 is connected in series with resistance 10, and in the third position the resistances 9 and 10 are cut out. In the fourth position a second field winding 3 on the second machine is connected across the armature 8 and arranged to oppose the field winding 7 which is shunted by the resistances 9 and 10. In the fifth position the resistance 9 is cut out and in the final position the armature 1 and field winding 2 of the first machine are short-circuited and the second machine operates as a generator to charge the battery 6, the field windings 3 and 7 assisting each other. When the vehicle is descending a long hill and the engine is stopped the controller is moved to a sprag and restarting position in which the first machine is included in a circuit containing a resistance and operates as a clutch. In this position also the second machine is shortcircuited to act as a brake during the backward movement of the vehicle. In the first braking and restarting position the second machine is connected in a circuit containing resistances 4 and 5, and the field winding 7 of the second machine is short-circuited when the controller is moved from the first braking position to the sprag and restarting position in order to prevent arcing. In the second braking position the resistance 5 is short-circuited. In the crank position the resistances 4 and 5 are connected in parallel, and an additional position is provided in which the first machine is connected with the battery to operate as a motor to start the engine. Further broking, cranking, and battery charging and braking positions are provided. A separate switch 15 may be included in the circuit of the first machine to cut out the restarting connections and this switch may be provided with a lock and key. Specification 18138/15 is referred to.