GB190907106A - Improvements in Synchronous Alternating Current Machines with Automatic Regulation of the Tension or Pressure. - Google Patents

Abstract

7106. Moser, R. March 24. [Addition to 6103/09.] Alternating-current commutator machines; rotary transformers; exciting.-Relates to the application to single-phase machines of the compounding arrangements for synchronous polyphase machines described in Specification 6103/09, and consists in removing alternating fields or converting them into rotary fields by the use of short-circuited brushes or a short-circuited winding upon the rotating field member. Fig. 3 shows one arrangement with a stationary armature winding s and a rotor provided both with a compounding commutator winding k and an exciting commutator winding e, which receives alternating-current through brushes z from a synchronously-driven six-phase exciter, or both currents may be led into the same rotor winding. The compounding-brushes x may be short-circuited. A single rotor winding may be supplied with single-phase exciting-current from a separate exciting - machine through brushes z, Fig. 5, displaced relatively to the compounding brushes x. Fig. 6 shows a further modification, in which in addition to the short-circuited brushes x, extra compounding-brushes y connected to a transformer in series with the main armature winding are employed. In place of short-circuited brushes, there may be a short-circuited rotor winding j, Fig. 11, and the two commutator rotor windings may in this case also be replaced by a single winding, the compounding and exciting currents being led in by the same or different brushes y, z. The short-circuited and commutator windings may be combined into one. Both the compounding and the exciting- currents may be polyphase, the single-phase current being converted into polyphase current by a phasetransformer, which may consist of a positivelycoupled commutator machine a<1>, Fig. 12, to which single-phase current-is supplied at the rotor through brushes bl and polyphase currents taken off at the stator d, or vice versa, with the help o f a shortcircuited winding or short-currented brushes b<2>. In arrangements with common exciting and compounding brushes yz, Fig. 12, the compounding-transformer and the exciting-machine d may be connected up in series, or in parallel &c. The exciting- machine is provided with a damping-winding on the field magnet, and may have a choking-coil in its continuous-current field circuit. For complete compounding, for example, if the voltage is to be kept constant at the points P1, P2, Fig. 12, an auxiliary synchronously-driven generator I is connected to the points P1, P2 so as to send current into the main machine, the exciting-machine d remaining coupled up but un-excited. The brushes yz, and b<1>, b<2>, and the compounding-transformer c are then so adjusted that the voltage at the points P1, P2 is stated to be brought down to zero. For incomplete compounding, the phase displacement between the machine current and voltage should amount to about 90 degrees. A variation of this arrangement, which is applicable also to the machines described in the above-mentioned Specification, consists in short-circuiting the conductors at the place where the voltage is to be maintained constant and connecting the auxiliary machine I in series at any desired place in a conductor, the parts being then so adjusted that the voltage becomes zero between the points interrupted by the auxiliary machine I. All the above-described machines may operate as motors ; for example, they may be run idly in a power station to keep the pressure on the mains constant.