GB845989A - Improvements relating to electrically propelled vehicles - Google Patents

Abstract

845,989. Control of several D.C. motors. ENGLISH ELECTRIC CO. Ltd. April 26, 1957 [April 26, 1956], No. 12804/56. Class 38 (3). [Also in Group XXXV] An arrangement for supplying a continuously variable voltage to motors TM1, TM2 of an electric vehicle comprises a supply transformer having a tapped secondary winding 10b whose sections 10b 1 . . . 10b 6 are associated with a switching arrangement including contactors C 0 . . . C 6 and a continuously variable autotransformer 16 which may be connected across each section in turn. A movable contact 16a which bears directly on the autotransformer winding is driven in either direction by a pilot motor 17 supplied from a D.C. source whose polarity may be reversed by a switch 18. The motors TM1, TM2 are D.C. motors as shown and are connected in a rectifying bridge network 13 and have series chokes 14, 15. The switching arrangement is controlled by a driver's controller which also controls the motor 17. In the first position with contactors C 0 , C 1 closed the transformer 16 is across the section 10b 1 and the voltage is raised as contact 16a moves from A to B. Contact C o is then opened and C 2 is closed thereby maintaining the voltage across the motors and contact 16a is then driven from B to A so increasing the voltage. The sequence is repeated through contactors C 1 , C 2 . . . C 6 until full secondary voltage is applied to the motors. In a modification (Fig. 3, not shown) the transformer 16 is supplied from an auxiliary winding, has two contrary moving contacts and is associated with a modified switching arrangement, and this modification may be further modified by the inclusion of a fixed ratio transformer between the transformer 16 and the motors. In alternative arrangements each half of a centre-tapped secondary winding may be treated as above.