Patent GB-563857-A (GB)
Title: An electrical control system for a warping or beaming plant
IPC: D02H3/00
Filed: 1942-07-24
Abstract: 563,857. Automatic control systems. LAMBACH, F. July 24, 1942, No. 10376. Convention date, Nov. 21, 1941. Drawings to Specification. [Class 38 (iv)] [Also in Group XXXVII] Current.-An electrically driven warping or beaming plant has automatic means whereby the speed of the motor is varied according to the depth of winding on the beam to maintain the warp yarns at a substantially constant speed. Creel switches responsive to the breakage of any yarn operate means to stop the motor and to ensure an inching or slow speed after repair of the yarn until the slack has been taken up. A manual switch in parallel with the creel switches may operate similarly. The plant may be associated with warp storage means comprising grippers on a frame operated at will by a reversible electric motor to clamp the yarns and withdraw them from the beam, switches operated according to the position of the frame co-operating with a switch actuated by the reversing switch for the reversible motor to ensure inching speed on restarting and automatic resumption of full speed when the storage device has yielded up the yarn. Braking means applied to the beam drive by a solenoid when the driving motor is stopped may be automatically relieved wholly or in part (to an adjustable extent) after a time delay to permit the withdrawal of yam by the storage means. In a modification having no storage means a torque motor operates a brake and simultaneously releases spring-actuated brakes on the beam pressure roll and on a measuring roll with which the warps pass. The effort of the torque motor is adjustable by a series resistance varied automatically by movement of the pressure roll. The motor is also dynamically braked by a resistance in shunt to its terminals. The beam driving motor is supplied from a D.C. generator, the excitation of which is determined by an exciter and a potentiometer manually adjusted to determine or vary the normal speed of the beaming plant. To maintain constant tension on the yarns a vibrating regulator subject to motor current intermittently short circuits a rheostat in the motor shunt field circuit. This rheostat is adjusted automatically by a pressure roll resting on the wound yarn to correlate the motor speed with the winding diameter. The generator field is connected to the exciter through an adjustable resistance determining an inching speed and a relay, controlled by a warp-break-sensitive relay or by an inching switch disconnects the potentiometer excitation when slow speed is required. When the " start " button is operated a contactor closes the field circuits of the generator ,and interconnects the generator and motor through an overload relay controlling the contactor coil circuit; the contactor also closes a maintaining circuit including a " stop " button, a contact of the warp-break relay and the coil of a time delay release relay which short circuits an adjustable choking coil in series with the brake-actuating solenoid the circuit of the solenoid having been opened by a relay coil in parallel with the contactor coil. This relay coil is adapted to control the circuit of the torque motor in the modification referred to above. The maintaining circuit of the contactor also passes through the normally closed contact of a counter stop relay which is energized to stop the motor when a desired quantity of yarn has been wound. A counter stop switch actuated by a revolution counter driven by the beam is adjusted to open after a given number of revolutions to de-energize a control relay which actuates the counter stop relay ; before the machine can make a continuous run a " reset " button must be operated to energize the control relay which then opens the counter stop relay circuit and closes a maintaining circuit for itself through the counter stop switch. The motor may be started after repair of a broken warp independently of the " start " button if the yarn clamping means on the storage means is in operation ; for this purpose the reversing switch controlling the motor of this device is set to cause the gripper frame to rise and a switch linked to the reversing switch is thereby closed to complete a circuit in parallel with the start button and including a switch closed by the clamping means, the gripper frame in its downward movement having closed a switch in parallel with the creel switches to cause operation of the warpbreak relay and consequent inching speed. When the frame rises to a position in which the grippers are about to release the yarns, and before the clamp releases, the inching switch opens and the motor accelerates to full speed due to increase in generator e.m.f. caused by re-application of the potentiometer excitation. In a modified plant having no yarn storage mechanism a three-position slipper rod is rotatable in two directions. In moving in one direction it closes in succession switches effecting inching and full speed respectively, and when released moves to a set position without actuating the inching switch. When moved in the other direction it stops the machine. Specifications 563,855, 563,856, 563,858 and 563,879, [all in Group IX], are referred to.