GB316111A - Improvements relating to the control of electric motors and generators - Google Patents

Abstract

316,111. Allan, J. E. March 15, 1928. Systems for continuous-current motors; controlling motors by varying terminal voltage; regenerative systems.-In the control of electric motors driving ships' winches and like machinery, the winch motor C, Fig. 1<A> which has a series field C<2> and a shunt field C<1> is connected across the mains in series with a generator B of a motor-generator set AB and the generator field is controlled by a series winding G in the circuit of the winch motor, for the purpose of adapting its speed and torque to the load and for maintaining torque under safe conditions when the motor is stalled in warping hawsers. In one arrangement, shown in Fig. 1<A>, the winding G acts to change connections between the generator field B<1> and a potentiometer D through which it is supplied with current. In a modification of this arrangement, the series winding switches in a small auxiliary motor which shifts contacts along the potentiometer resistance. In the arrangement shown in Fig. 1D, a negative series winding BG is provided in the field of the generator, and may be switched in automatically by a series responsive coil. To provide for regenerative braking the arrangement shown in Fig. 1E has the motor series field C<2> and the generator negative series field BG connected across a short-circuiting switch which may be closed automatically by a polarized relay. A detailed description of the circuit connections of the last mentioned arrangement is given in the Specification. The working motor and the motorgenerator set are perfectly enclosed in casings which are automatically opened to afford ventilation when the machines are running, the apparatus therefor being described in Specification 315,687, [Class 35, Dynamo-electric generators &c.].