Device for controlling the load of a three-phase generator in a three-phase system with at least two parallel connected, each separately driven three-phase generators

摘要

767,057. Running generators in parallel; automatic electric power control systems. ROTOL, Ltd. Oct. 4, 1955 [Oct. 11, 1954], No. 29291/54. Addition to 732,052. Drawings to Specification. Class 38 (4). In the control system for maintaining a predetermined load division between parallel working three-phase generators described in the parent Specification, wherein the power input to one machine is automatically varied upon deviation of the predetermined load division by a two-phase motor having one phase winding connected across two lines of the A.C. system and the other phase winding energized from the opposed secondary windings of current transformers having primary windings in the third lines, respectively, of the controlled machine and of either the system as a whole or the other machines, the secondary windings are now connected in parallel with one another, instead of in series, and the output of the winding of the transformer associated with the controlled machine opposes that of the other transformer or transformers. The transformation ratios of the transformers are made such that their effective output for energizing the motor is zero when the correct load division obtains. The switching out of any generator may also vary the ratio of the transformer associated with the controlled machine, so that it is now readjusted for correct load-sharing with the remainder of the machines in service.