Patent GB-459419-A (GB)
Title: Improvements in or relating to electric motor control systems
IPC: B65H23/18
Filed: 1936-03-18
Abstract: 459,419. Control of two D.C. motors. IGRANIC ELECTRIC CO., Ltd., 147, Queen Victoria Street, London.-(Assignees of Horter, B. M.; 315, North 12th Street, Milwaukee, Wisconsin, U.S.A.) March 18, 1936, No. 8117. Convention date, March 25, 1935. [Class 38 (iii)] Travelling to predetermined limits ; non- regenerative braking ; armature control.-Two dynamo-electric machines M1, M2 having shunt fields F1, F2 are employed for transferring material from either of two rolls 1, 2 to the other, and means are provided for selectively establishing power connections for the armatures A1, A2 of the machines to effect starting of either one as a motor, and rendering the other operable as a braking generator, the establishment of the braking connections taking place an interval following starting. The rolls may be those of dye-jigger in which cloth is passed through a bath in opposite directions. Upon operation of a start switch 9 a self-maintaining main switch 4 is closed, and a winding 14 of a relay 12 is energized to operate the relay to a position in which it energizes a self-maintaining reversing relay 5. The machine M1 is thus connected to the supply with resistances R1, R2 in series, and operates to wind material on roll 1, unwinding it from roll 2. When the relay 5 operates, it connects the coil 7a of a relay 7 across the armatures Al, A2, so that, when a predetermined speed is attained, the relay 7 operates to connect the armature A2 across resistances R1, R2, R4. Thus, the machine M2 operates as a braking generator, and, by regulation of the resistance RH, which is now included in the circuit of the motor M1, the tension of the material may be adjusted. If a start switch 10 is operated instead of the switch 9, the motors M1, M2 are similarly controlled, but the relay 12 is moved to its other position and the machine M2 acts as a motor and the machine M1 as a generator. When the relay 12 is operated to reverse the direction of the material, the closed reversing relay and the relay 7 must drop out before the other reversing relay can be closed. A switch 19 is adapted to be opened by a cam on the arm of the regulating resistance RH, when the amount of resistance included is sufficient to prevent operation of the machine associated with the unwinding roll as a generator. Thus, when all the material is wound upon either roll, the switch 19 may be opened to prevent response of the relay 7 and thus prevent operation of the machine associated with the full roll as a braking generator. Depression of a stop switch 11 de-energizes the switch 4 which de-energizes the machine operating as a motor, and completes, at contacts 4c, a braking circuit for the machine operating as a generator. Prior to winding any material on each roll, counting devices 21, 22 associated with the rolls may be set at zero and switches 27, 28 closed. Thus, when during the operation of the equipment all material has been unwound from a roll, the corresponding counting device returns to zero and closes a switch 23 or 26 which reverses the relay 12 and effects automatic reversal of the equipment. For rocking the rolls when all the material is wound upon either, switches 29 and 30 are closed, and switches 24, 25, associated with the counting devices, control the relay 12 to effect automatic reversal of the equipment upon given relatively small angular movements of the rolls, for example, four revolutions thereof.