Patent GB-785478-A (GB)
Title: Improvements in or relating to control systems for electric winder motors
Inventor: FRIEDLANDER ERICH SIEGFRIED
IPC: B66B1/12
Filed: 1955-04-28
Abstract: 785,478. Control of motors; controllers. GENERAL ELECTRIC CO., Ltd. April 27, 1956 [April 28, 1955], No. 12316/55. Class 38 (3). A cam 18 driven by a winder motor controls the deceleration of the motor as the cage approaches a stopping-point, the rate of deceleration of the motor is a load-dependent factor, and the initiation of electric braking is delayed, also in dependence upon the load. As shown, movement is transmitted from the cam 18 to a speed-pattern potentiometer 19 by means of pivoted lever arms 21, 23, interconnected by a link 26 having a variable pivot point 17, the position of which is changed in accordance with the motor load. A cam 13 is rotated to a position dependent upon the load, so that when the cage reaches a predetermined point in its travel, the cam 18 becomes effective to move contact 25 over potentiometer 19, the contact being initially between the points x and y. Deceleration commences when the contact 25 reaches the point y. The greater the load, the nearer is the contact to the point x when the lever arm 21 commences to move, and the speed of movement of the contact is also greater. Thus, with higher values of the load, the cage approaches closer to the stopping-point before deceleration is initiated, but the rate of deceleration is greater. The load-sensitive device comprises a power torque motor 1 having windings respectively energized in accordance with winder motor current and voltage, and a brake torque motor 4 having one of its windings connected in series with the rotor winding of an induction regulator 7. The rotor of the induction regulator and the cam 13 are driven from the common shaft of the motors 1 and 4. In another arrangement two differential mechanisms are provided, one for effecting displacement of the decelerating cam relative to the position of the winder cage, and the other for altering the speed ratio between the winder motor and the decelerating cam, Fig. 3 (not shown). In a further modification, particularly suitable for alternating-current winder motors, a tachometer generator is driven by the motor and has its field excitation varied in dependence upon the load. The output voltage of the generator opposes a second voltage dependent upon the position of the cage, and electric braking of the winder motor is delayed until the second voltage is less than the output voltage, Fig. 5 (not shown). Another loadsensitive device comprises current transformers 60, 61, connected to the coils of a bi-phase wattmeter torque system 63 which controls a constant-speed regulating motor 64. According to whether the load is above or below a given datum value, either contacts 65 or 66 are engaged by contact 67 to rotate the motor 64 in one direction or the other. An induction regulator 84 is driven by the motor 64 to supply the opposed coils 88, 89 of a polarized relay 90 affecting a control upon the position of the contact 67. Thus, rotation of the motor 64 continues until the torque produced by relay 90 balances that of the system 63, whereupon neither of the contacts 65, 66 is closed, the motor being brought to a quick standstill by direct-current excitation. The contact arms of face-plate regulators 82, 83 are driven by the motor 64, these regulators having contact studs connected to a pattern speed potentiometer 91 having a movable contact 92 driven by the decelerating cam. A voltage signal for controlling the slow-down of the winder motor is developed across winding 93 connected in series with tachometer generator 94 so that deceleration can only commence when a voltage dependent upon the position of the contact arm of the regulator 83 is less than the output voltage of the tachometer generator. The rate of deceleration of the winder motor depends upon the position of the contact arm of the regulator 82 since this regulator determines the voltage per unit length across the potentiometer and thus the change in voltage signal per unit distance moved by the contact 92.