GB193692A - Improvements in control systems and apparatus for dynamoelectric machines - Google Patents

Abstract

193,692. Cachemaille, A. S., (Westinghouse Electric & Manufacturing Co.). March 8,1922. Electric motor control systems.-Relates to control systems and apparatus for a number of motors grouped in pairs and having shunt fieldwindings, each pair working independently as in the propulsion of submarines. Systems for continuous-current motors; seriesparallel systems.-Each pair of motors is provided with armature resistances, not shown, field resistances consisting of two equal sectional resistances 40, 41, Fig. 2, a master controller 34, and a series-parallel drum 35. The arrangement allows armature-circuit control and field-circuit control to be effected successively and permits change from series to parallel, or vice versa, only during armature circuit control. The field strength of the two motors is first equalized by adding the necessary amount of resistance to the field of one of the motors by means of a rheostat switch 37. In the preparatory stage of control, the resistances 40, 41 are gradually cut out of the field circuit. Continued movement of the master controller successively connects the motor armatures in series, cut out armature resistance, and connects the motor armatures in parallel. The final stage of control reinserts resistance in the field circuit. Similar sequences of operations take place in reverse running, for which the lower portion of the speed drum, as shown in Fig. 2, is used. A separate series-parallel master switch 35 is inferlocked with the speed drum. A change-over switch 38 allows the field to be connected direct to a battery 39 in case the master controller is out of action. Controllers, drum.-The complete controlling gear for two pairs of motors, as shown in Fig. 6, comprises two master controllers 108, 109 actuated independently of each other by hand wheels 104, 105 through chain and sprocket gearing. Each hand-wheel has obstructing notches and a releasing pin 136 which must be depressed before the wheel can be moved from the initial position. The series-parallel switch 35 actuated by a removable handle 126, and two drum-switches 36, 120 for cutting out either motor of a pair at will, actuated by handles 106, 107, are mounted with the master controllers in a compartmented casing with the actuating handles on the outside. Controllers, interlocking. - Mechanical interlocks between each of the hand-wheels and the series-parallel handle 126 prevents the seriesparallel switch from being moved from an operating position to the off position unless the master controller occupies either the off positions or one of the series actuating positions, and reciprocally prevents the hand-wheels from being moved from these positions if the series parallel switch is'in its off position.