GB725609A - Improvements in or relating to electric motor control systems - Google Patents

Abstract

725,609. Exciting electric motors. BROWN, W. H. May 7, 1953, No. 12743/53. Class 35. [Also in Group XXXVII] Parallel-connected motors 10, 11, 12 driving separate traction wheels or like loads, each have a main shunt field winding 19, an accumulative series field winding 16, and a differential series field winding 18. Each winding 16 is connected between one side of its armature and a common point 17, the windings 18 being connected in parallel between this point and one side of the supply. The arrangement is such that the impedances of the several parallel branch circuits are the same. The speeds of the motors are set in common by a rheostat 23 and individually by rheostats 22, and any variation in the relative speeds of the motors is corrected by changes in the value of the line currents and by the setting up of cross-currents between the motors when the relative loading changes; an increase in the armature current of one motor being shared by equal increases in the currents passing through the differential field windings 18. The motors may be of the series traction type, Fig. 2 (not shown), having opposing field windings of unequal number of turns. The system may be used for preventing excessive wheel-slip or sliding in vehicles. Reference is also made to the control of several motors driving a multiple block wire-driving machine, Fig. 3 (not shown). The circuit arrangement may comprise a number of parallel branches each consisting of a pair of motors connected in series, Fig. 8 (not shown).