GB191222270A - Improvements in and relating to High Voltage Continuous Current Dynamos. - Google Patents

Abstract

22,270. Girvin, C. W. Oct. 1. Commutators; windings; rotary transformers; dynamos, regulating; motors, controlling.-The stationary coils of a rotating-magnet open-coil armature are connected to subdivided rows of brushes bearing on a rotary commutator which adds their voltages and enables high-potential continuous currents to be generated or supplied to a motor. The developed connexions of a bipolar machine having sixteen coils are shown in Fig. 1, and those of four neighbouring coils in three successive commutator positions are shown in Figs. 5, 4, and 6, respectively. The open coils a, b, c, d .. are connected at each end to brushes 1, 2, 3, .. 8, which, in the form shown, are arranged in rows of eight parallel to the axis of the commutator which has a corresponding number of rows of segments. Two outer rows of segments S are also provided for brushes 33, 34, .. 40 having leads T1, T2, .. T5 for interconnecting the groups of coils and for leading current to or from the machine. The segments are so interconnected by links u and resistances r', r<2> that the voltages of the coils a, b, c .. are added, and the coils are bridged by the resistances during the short-circuit periods. The four coils a, b, c, d, Fig. 4, are shown with the coil d undergoing commutation, as in Fig. 1, namely, with the brushes 7, 8 connected by the resistance r<1> and the other coils sending current from T<2> to T'. Just before this position, the coils are as shown in Fig. 5; i.e., all carrying similarly-directed currents, and just afterwards they are as in Fig. 6, i.e., with the current in coil d reversed and its connexion between the brushes 34 and 6 reversed by the conductor u to maintain the voltage addition. The coils c, b, a are similarly short-circuited and reversed in succession. The commutator may be mounted on the magnet shaft or it may be driven separately. In the form shown in Fig. 15, the armature coils are divided into two groups connected to separate commutators 49 driven by sprocket chains 51 from the shaft of the magnet 50. The groups of coils may be connected to form separate generating circuits, or some may be supplied with motoring currents while others generate. Alternatively, some may be permanently connected together to give alternating-current. The conductors forming the individual coils may be interconnected in series or parallel to enable the voltage of the coil to be varied or to allow the speed of a motor to be controlled without resistance, and coil units separated by more than one polepitch may be connected together provided that their position is such as to give the correct addition of voltage.