| 摘要 |
<p>1461433 Automatic control CUTLER-HAMMER EUROPA Ltd 26 June 1974 [27 June 1973] 28431/74 Heading G3N A control system for supplying energy to the armature of a D.C. motor is responsive to a command signal changing at a pre-set rate and incorporates a clamping means responsive to the difference between the command signal and a speed feedback signal to modify the rate of change of the command signal. As shown, Fig. 1b the armature a of a D.C. motor M is energized from a three-phase supply L1-L3 through SCR's SCR1-SCR6 commutated by a firing control circuit 10 responsive to a control signal between a line 12 and ground 14. The motor has a shunt field f and drives a tachogenerator T.G.' A D.C. signal representative of armature current is derived by transformers 16, 18 and a bridge 20. The control system, Figs. 1a, 1b comprises operational amplifiers Z1-Z6 of which Z6, Z5 provide a desired speed signal in accordance with the setting of PR1, determining a desired speed, and PR2, which in dependence on feedback through capacitor Cl, determines the rate at which a desired speed is attained. The speed error is detected by the operational amplifier Z4 and integrated by the operational amplifier Z3 adjusted by a potentiometer PR5 coupled to a potentiometer PR4. The output of the operational amplifier Z3 is applied to the input of the operational amplifier Z2 together with a speed-error spill-over signal from a circuit 40 connected to the operational amplifier Z4 whereby a step increase in voltage is applied for large speed errors. The output of the operational amplifier 22 is applied to the operational amplifier 21, providing the control signal to circuit 10, through a current limit clamp circuit 34 the level of which is set by potentiometers PR6, PR7.</p> |
