Patent GB-208396-A (GB)
Title: Improvements in electric starters for internal combustion engines
IPC: H02K23/52
Filed: 1923-01-04
Abstract: 208,396. Barenyi, K. A., and Kaemmerer, P. Jan. 4, 1923. Dynamos, regulating; motors, controlling; commutators; windings.-An electric starter for an internal-combustion engine has a switch connected to the armature windings and commutator segments so that the armature may have a high or a low resistance according to whether the machine operates as a generator or as a motor. In the winding shown in Fig. 1, one end of each coil 1 - - 12 is connected to a commutator segment I - - XII, and the other end to a switch 11 - - 12'. With the switches in the positions shown in dotted lines, all the coils are in series, and the machine operates as a generator with the narrow brushes b1, b2 on the commutator. For operation as a motor, the switches occupy the full-line positions so that pairs of coils 1, 2 &c. are in parallel and the broad brushes b3, b4 rest on the commutator. The field coils mav be subdivided so that for motoring the sections are all parallel with each other and in series with the armature. Fig. 6 shows a form of switch for effecting the change in the armature connections. The free ends h of the coils are joined by flexible leads i to insulated springs m mounted within a drum o and bearing against the end faces of the commutator segments c. The drum o is secured to a shaft q by a bolt r passing through circumferential slots t in the hollow shaft p. For starting the engine the drum is advanced by means of the shaft q through a distance corresponding to that between two commutator segments, and the coils are connected in parallel. To operate the system as a generator the shaft q is turned in the opposite direction whereupon all the coils are in series. In the winding shown in Fig. 9, the generating coils 1<a> - - 6<a> are joined in the usual way to the commutator segments I<a> - - VI<a>. Additional segments I<1a> - - VI<1a> are provided between the main segments and are connected as shown to motoring windings 1<1a> - - 6<1a> embedded in the same slots as the main windings. For motoring, both sets of coils are connected in parallel by means of the short-circuited switches d, and for generating, the windings 1<a> - - 6<a> only are used. In another modification, the coils of the different windings are embedded in separate alternate, slots. both windings being in parallel for motoring and in series for generating; a single pair of brushes is employed and each brush covers two segments. Fig. 11 shows an example in which the windings each consist of two sectional coils 1<c>, 1<1c>, &c. The coils 1<c> - - 6<c> have a high resistance and are connected in series for generating with the switches k1 - - k6 in the dotted positions. For operation of the system as a motor, the switches occupy the full-line position and the coils 1<1c> - -6<1c> are in series, the other winding being switched out. In other modifications, a single coil is employed, a part being used for motoring, and the remainder or the whole coil for generating. A form of switch for altering the armature connections automatically is shown in Fig. 14. The armature is secured to a shaft 71 co-axial with another shaft 72 connected to the engine. Slots 74 in the part 72 engage with clutch-members 75 secured to the armature shaft so that the two shafts can move relatively through an angle corresponding to the distance between two commutator segments. The armature coils are connected by leads 81 to the commutator segments 76 and by leads 82 to insulated spring-contacts 78 bearing on the end faces of the segments and carried by a ring 77. The ring 77 is secured to the shaft 72. When current is switched on, the armature rotates relatively to the switch ring, and the spring- contacts connect up the armature for low resistance. As the engine accelerates and overruns the motor, the switch connects the armature for high resistance and the machine operates as a generator. Figs. 18 and 19 show a construction in which the ends of the armature coils are not connected in part to the commutator segments. but in which pairs of coils can be connected alternatively to the same segments. The ends 101, 101<1> of the coils are brought out through a pair of holes in each segment 96, and are connected to insulated contact plates 102, 102<1> embedded in the segments. A sleeve 92 which is movable relatively to the armature shaft is connected to the engine shaft and carries a switch ring 97. The switch ring carries springs 113 to each of which is secured a contact plate 114 bearing against the end faces of the segments and the contact plates. The switch ring can be moved through a distance corresponding to half the breadth of a segment, and consequently either the high-resistance coils or the lowresistance coils can be connected to the commutator. In order to avoid the necessity of moving the brushes when the operation of the machine is changed, the coils of the motor and generator windings in the same slots are connected to segments disposed at an angle equal to the angle between the neutral zones, and the brushes are fixed in intermediate positions.