Patent GB-221176-A (GB)
Title: Improvements in and relating to the conversion of electric currents
IPC: H02M7/54
Filed: 1923-10-29
Abstract: 221,176. Kukel, S. A. Aug. 28, 1923, [Convention date]. Systems of charging and discharging galvanic batteries; systems depending on the use of static transformers.-In a converting arrangement comprising a battery of accumulators and one or more commutators, each having a series of contacts connected to individual elements of the battery, some of the contacts are made of substantially greater width than the others. In the arrangements shown in Fig. 2, the wider contacts a<1>, a<1> are connected to the end terminals of the battery 1 - - 3, the narrower contacts a being connected to intermediate points of the battery. The battery is charged from or discharged into an alternating-curent circuit through fixed slip rings B<1>, B<2> and rotating brushes. In another arrangement, Fig. 3, two commutators A', A<2> are employed, each having a pair of wide contacts a<1> and two series of narrower contacts a of increasing width, the increase in width in one commutator taking place in a clockwise direction of rotation, and in the other commutator in an anticlockwise direction. A pair of brushes c<1>, c<2> and slip rings are provided for each phase of the alternating current, the widths of the contacts being in accordance with the wave-form desired. Resistances g are inserted in each lead or in alternate leads to the elements of the battery to prevent momentary short-circuits in passing from one contact to another. In order to ensure a more uniform utilization of the different elements of the battery, change-over switches h may be provided for periodically varying the order of succession of the elements, or a third commutator may be provided and connected' in opposition to the other two to compensate for the excessive charge or discharge of the middla - elements of the battery. The frequency or number of phases of an alternating current may be changed by charging the battery through one set of commutators and discharging it through another set. An arrangement for supplying a three-phase circuit C from a single phase source S is shown in Fig. 8, the arrangement comprising a single battery and set of commutators connected to the alternating-current side through a tapped three-phase transformer T<3>. The rotary members of the commutators are driven by a motor M<1> connected to the three-phase circuit through a transformer T<4>. The battery and commutators may also be connected to an alternating-current circuit for improving the power factor or for supplying boosting currents. Such an arrangement is shown in Fig. 9, the battery being charged from, or discharging into, the threephase circuit S through a transformer T<3> connected to a voltage-regulator VR. Any desired phase relationship between the threephase current supplied by the generator and the current delivered to or from the battery may be obtained by adjusting the relative positions of the rotary elements of the driving motor M<1> and the commutator. A number of batteries, separately charged from an alternating-current supply through commutators and high-voltage transformers . may be connected in series for highvoltage direct-current power transmission. The individual cells of the battery may be of very small capacity and similar in construction to the electrolytic safety devices used for excess voltages.