GB622192A - Improvements in and relating to slip regulators for motor generator sets - Google Patents

Abstract

622,192. Electricity supply; automatic control systems. BRITISH THOMSON-HOUSTON CO., Ltd., PETCH, T. H., and LIDDIARD, H. W. C. Nov. 16, 1944, No. 22659. [Class 38 (iv)] In a motor-generator set having a fly-wheel F rigidly coupled to the shaft of the generator C, an eddy-current slip-coupling between the generator and the motor M is controlled by means responsive to the motor input to maintain the said input constant. The driven half C1 of the coupling has a D.C. field winding CF connected in series with the armature A of a separately-driven amplidyne exciter having one field winding AFM connected through a potentiometer PR to a fixed D.C. source, a second field winding AFC being connected in opposition to winding AFM and energized in accordance with the motor input current through a rectifier R and current transformer T. Thus if the motor input current tends to vary above or below the setting of the current in winding AFM, due to a fluctuation in load on the generator, a resultant flux is produced which causes the amplidyne to buck or boost the current in the winding CF, thereby varying the slip of the coupling and causing the fly-wheel F to impart energy to the generator for an increased load or to absorb energy from the motor for a decreased load. Since the motor input and speed are thereby maintained constant, a synchronous motor may be employed. Hunting may be obviated by the provision of a transformer ST whose primary is connected across the armature A and its secondary connected to a third field winding AFS. If it is desired to prevent the amplidyne boosting the field winding CF appreciably, a fourth field winding AFL may be connected in opposition to winding AFM through a rectifier R1 to the terminals of armature A and so proportioned that when boosting occurs it neutralizes the effect of winding AFM.