GB1383028A - Electric motor drive systems - Google Patents

Abstract

1383028 Automatic torque control ALLMANNA SVENSKA ELEKTRISKA AB 2 June 1972 [3 June 1971] 25836/72 Heading G3R In a system having a main shaft driven by at least one main motor, and an auxiliary shaft driven by at least one auxiliary motor, the torque on a shaft connecting the main and auxiliary shafts is measured and used to automatically control the auxiliary motor thus regulating the torque to a predetermined value. In the embodiment, three phase A.C. commutator motors M 1 -M 4 , fed from supply 12 through controllers S 1 -S 4 , drive a folder F 1 and printing machines U 1 -U 3 via main shaft 13, connected by shaft 18 to auxiliary shaft 15, also driven from supply 12 by auxiliary shunt-wound D.C. motors M 1 1 -M 13 through thyristor converters 22-24. A "coarse" torque control signal is calculated from the power supplied to the main motors M 1 -M 4 , the speed of shaft 13 as measured by tachogenerator 14, and the number of motors to control the torque on shaft 15, in a feedforward manner. In a rectroactive torque control loop, a "fine" torque control signal is calculated by operational amplifier 20 having a PI or PID characteristic, from the torque on shaft 18 as measured by transducer 19, and is fed to a proportional regulator 28, that has a signal limiter, to provide a reference to converter current regulator 29 and regulate the torque in shaft 18 to zero. An inner speed regulating loop uses a signal proportional to the speed difference of shafts 13, 15, as measured by tachogenerators 14, 16 and calculated by regulator 21, to form a further signal to regulator 28 and maintain shafts 13, 15 at the same speed.