Patent GB-133643-A (GB)
IPC: H02K23/50
Abstract: 133,643. Tower, C. H. Sept. 10, 1918. Machines with two or more armatures; rotary machines; brush-holders; commutators and collecting- rings; cores and yokes.-A high-tension alternating-current dynamo for igniting in internal-combustion engines and a low-tension continuous-current dynamo for lighting, battery-charging, &c. are combined in a single structure. A rotating field magnet 24 carrying an exciting winding 25 acts inductively upon a slotted armature 9, the winding 8 of which is connected to a commutator 12, and also upon a second armature 18 carrying high-tension and low-tension windings 20. The air-gap between the field magnet 24 and the armature 18 is very narrow as compared with that between the field magnet 24 and the armature 9, and the iron parts of the armature 18 are designed so as to reach saturation approximately simultaneously. Rotating brushes 28 bear upon the commutator 12, these brushes being: mounted upon an insulating disk secured to the shaft 21. Current is conveyed from the brushes to stationary terminals 101 on an end plate 4 by means of slip-rings 35, 36 and brushes 40, 41, Figs. 1 and 4. One end of the winding 25 is joined by a lead 25a to a spring-conductor 38, while the other end is connected to a slip-ring 37. A combined distributor and interrupter is mounted on an end plate 6 and includes shafts 48, 51 driven by skew gearing from the shaft 21. The interrupter comprises a fixed electrode 69 carried by an adjustable ring 71 and a movable electrode 72 secured to a lever 73 which is oscillated by a cam 75 on the shaft 48. The spring 76 for the lever 73 also connects the lever electrically with an insulated terminal 77. The ring 71 is adjusted by means of an arm 78; the condenser 79 is fixed to the housing 46. High-tension current is led by a contact 63 and a conductor 60 to the central contact 56 of the distributor, the other end of the high-tension coil being earthed. The rotating contact 55 of the distributor is fixed in an insulating block at the top of the shaft 48. The distributor cover 58 and a cover 65 for the safety spark-gap 64 are fixed by spring clips 59, 66 respectively. The circuitarrangements and control-switch 80 are shown in Fig. 6; the conductor 96 may or may not be grounded at 100. In the position, shown in full lines, of the switch-arm 81 for starting the engine, current passes from the battery 93 through the low-tension winding 20a of the ignition dynamo; in the second starting position a, both the winding 20a and the exciting winding 25 are excited by the battery. As the engine gathers speed the switch-arm 81 is moved to either of the positions b or c; in position b, the battery current flows only through the winding 25; in position c, no battery current flows through the windings 20<a>, 25, but the field-magnet winding 25 is excited with continuous current from the armature winding 8. As soon as the generator speed becomes high enough, the cut-in switch 97 closes, and the low-tension generator charges the battery. With the switch arm 81 in the position d, the circuits are opened and the engine stopped. Features of the invention are stated to be applicable to ignition dynamos apart from their association with the continuous - current machines. Specifications 11244/14, 119,254, and 136,203 are referred to.