Patent GB-662735-A (GB)
Title: Carbon pile electrical regulators
IPC: H02P9/22
Filed: 1948-07-27
Abstract: 662,735. Automatic regulators; automatic control systems for supply systems depending on variable-speed generators. GENERAL MOTORS CORPORATION. July 27, 1948 [Aug. 23, 1947], No. 19995/48. Class 38 (iv). In a carbon pile regulator the armature of the electromagnet is attached to a blade hinge which is adjustably attached to a bracket which is, in turn adjustably mounted on a magnet frame carrying the electromagnet winding and spring means urge the armature away from the magnet. In a carbon pile automatic voltage regulator, Figs. 2 and 6, a stack of carbon discs 24 in a refractory insulator tube 23 is housed in an aluminium casing 21 supporting a magnetizable bracket 25 to which is riveted a magnetizable bracket 26 carrying an iron-cored electromagnet 40. An armature 60 is hingedly connected by a flexible bimetallic strap 61 to a bracket 50 mounted on bracket 26. Elongated openings for fixing screws permit adjustment of the relative position of bimetallic strap 61 and bracket 50 and the relative position of brackets 26 and 50. An arm 70 attached to the armature carries an insulated plate 104 on which is mounted a screw 103 carrying a contact 102 co-operating with the spherical portion of a contactor 101 engaging one end of the pile. The other end of the pile is engaged by a contactor 107 carried by an insulated adjusting screw 108. The pile is compressed by adjustable tension springs, Figs. 5 and 5A (not shown), which act on arm 70 and may be made of flat stock designed to allow for variations of the gap between armature and core. Movements of the regulator are damped by a dashpot having an oil-filled cylinder 84, fixed to arm 70, and a piston 87 attached to a flexible diaphragm 88 and to a piston rod 86 held at its far end in a selfaligning bearing 95. Three terminals for external connections are mounted on an insulating block. A carbon pile automatic current regulator, Figs. 8 and 9 (not shown), is described and differs only in the type of electromagnet winding and the arrangement of terminals. A voltage regulator and a current regulator attached to a finned aluminium heat radiator and mounted in a metal container is described, Figs. 10 and 11 (not shown). As applied to the automatic regulation of a generator-battery supply for a motor vehicle, Fig. 12, a generator 160 driven by the engine is normally connected in parallel with a battery 187 through a cutout 180. A carbon pile regulator 20, the winding 40 of which is supplied through a potentiometer 200 with a portion of the generator voltage, and a carbon pile regulator 130, the winding 132 of which is energized by the generator current, are arranged with their piles 24, 24<SP>1</SP> in series with generator field winding 164. In order to reduce the duty of these regulators a relay 220, which is operated when the voltage across the series-connected piles 24, 24<SP>1</SP> exceeds a predetermined value, connects in parallel with field winding 164 the pile 213 of a further carbon pile regulator 210, the winding 250 of which is connected across piles 24, 24<SP>1</SP>. This further regulator is arranged, Fig. 9A (not shown), so that its spring tends to increase, and its winding to reduce, pile resistance. On starting, a relay 172 is only energized sufficiently to close contacts 195, 197 and close cut-out 180 when the generator voltage reaches a predetermined value. Thereafter, the battery remains connected unless the generator voltage falls to such an extent that contacts 196, 198 of relay 172 close to open cut-out 180.