GB398989A - Improvements in and relating to electric propulsion systems - Google Patents

Abstract

398,989. Control of two D.C. motors. BRITISH THOMSON-HOUSTON CO.. Ltd., Crown House, Aldwych, London.-(Assignees of Beekman, R. A.; 38, Washington Avenue, Schenectady, New York, U.S.A.) July 25, 1932, No. 20962. Convention date, July 24, 1931. [Class 38 (iii).] Varying e.m.f.-In an electric ship propulsion system comprising a number of motors and a number of generators not a multiple of the number of motors, the voltage of a number of generators which is a multiple of the number of motors is variable and reversible and each of the motors can be connected independently to at least one of the variable voltage generators, and all the generators can be connected to the motors when the variable voltage generators are operating with full field. As shown applied to a system employing three generators 1, 2, 3 and two motors 4, 5, the fields 36, 47 of the generators 1, 3 are supplied through controllers 42, 53. With switches 6, 8 in the left-hand position and the switch 7 in the.position shown motors 4, are fed separately from the generators 1, 3 which are independently controlled. Generator 2 may replace generator 1 by throwing switch 6 to the right and similarly it may replace generator 3 by throwing switch 8 to the right. The field 56 may be fed through either controller 42, 53 by appropriate manipulation of switches 57, 39 or 50, an interlocking bar 66 preventing simultaneous connection of both controllers to the filed. When independent control of the. motors is required switches 6, 8 are thrown to the left-hand positions and switch 7 may be in the position shown or thrown to the right so that generator 2 when excited can supply a separate circuit 34, 35. For maximum speed, switch 7 is thrown to the left thus connecting all the generators and motors in an uncompleted series circuit which is completed by the closure of a contactor 9 when both controllers 42, 53 are in the full speed ahead position. The energizing coil of contactor 9 is fed from bus-bars 45, 46 through contacts 68, 70 and a segment 69 on controller 42, similar contacts 72, 74 and segment 73 on controller 53, and contacts 78,79 on switch 7. At the same time, switch 60 is energized to connect the field 56 of the generator 2 to the bus-bars 45, 46, this switch if necessary including resistance contact and a time-delay device 63. If either controller is moved from its full speed ahead portion contactor 9 and switch 60 are de-energized so that the series circuit is broken and the generator 2 cut out, but separate circuits for the other generators and the motors are maintained independently of the switch 7 by contactors 10, 11 fed from the bus-bars 45, 46 through contacts 92 on the switch 60 and the two upper contacts and associated segments of either of the controllers which keep their circuit closed at all positions other than that for full speed ahead.