Improvements relating to rheostatic braking of electrically propelled vehicles

摘要

347,381. Control of D.C. motors. JOHNSON, C., 9, Stanmore Avenue, Stretford, Manchester, and ASSOCIATED ELECTRICAL INDUSTRIES, Ltd., Bush House, Aldwych, London. Feb. 28, 1930, No. 6714. [Class 38 (iii).] Non-regenerative braking ; reversing.- A tramcar is provided with two groups of motors, the armatures of the two motors in each group being permanently connected inseries. In the " forward " position of the controller at one end of the vehicle the motors are arranged as shown in Fig. 1, the field Fl being that of the armature A1, and the others likewise. In the " backward" position of this controller each pair of armatures is reversed as a whole. In the " braking" position, Fig. 2, each pair of armatures is reversed as a whole and substituted for the other pair, an equalising connection E and braking resistance R being added to the circuit. This gives a cross-connected fieldarmature system that will have a braking effect whichever direction the tramcar runs and the equalizing connection E ensures that should a disconnection occur in any one circuit, there is still a braking effect for each direction. The controller at the other end of the tramcar gives the connections shown in Fig. 4 when in its " forward " position, and interchanges the groups of armatures in the same sequence as the first-mentioned controller in its " backward " and " braking " positions, with the result that in the " braking " positions of either controller, each armature is associated with the same cross-connected field.