Patent GB-270737-A (GB)
IPC: H02K17/38
Filed: 1927-05-05
Abstract: 270,737. International General Electric Co., Inc., (Assignees of Allgemeine Elektricitõts-Ges.). May 5, 1926, [Convention date]. Alternating - current commutator and induction machines; rotary converters and transformers.-The regulation of the effective and wattless components of an induction machine connected in cascade with a 3-phase commutator machine is carried out by means of two regulating devices respectively dependent upon the two components and such that they operate at different speeds, the one being comparatively quick-acting and the other comparatively slowacting. The invention is described with reference to a known arrangement, Fig. 1, of a frequency converter for coupling two systems of different frequencies. In this arrangement the primary side of the induction machine v is connected to the network n and its secondarv side is connected through slip-rings s to the commutator k of an alternating-current machine coupled to a synchronous or induction generator g which feeds back to the network. The second network of different frequency from that at n may be connected to the conductors leading to the rings s or to another generator coupled to the machine v. The regulation of the effective and wattless output components of the machine v is effected by two double rotary transformers or induction regulators fed at slip frequency and having their primary and secondary winding a - d, and a<1> - - d<1> respectively connected in seriesparallel and series. The secondaries of the in. duction regulators are connected in series with a stator winding a on the commutator machine. The machine a, b, a<1>, b<1> regulates the effective component and the machine c, d, c<1>, d<1> the wattless component. According to the invention, the regulating devices controlling the induction regulators are given different speeds of operation whereby they work independently of each other and hunting of the induction regulators is prevented. In the form shown in Fig. 2, the coil f is excited by an exciting machine e, mounted on the shaft of the main machine v and fed by two induction regulators a, b, a<1>, b<1>. c, d, c<1>, d<1>, which have regulating devices operating at different speeds. Alternatively, the commutator machine k may be mounted on the shaft of the machine v and fed through slip-rings directly from the induction regulators. Or the machine k so mounted, Fig. 4, mav be fed by an exciter e of synchronous type driven by a synchronous motor m and having two continuous-current field coil systems w<1>, w<2> placed in quadrature so as to control respectively the effective and wattless components. The regulators r', r<2> of these are respectively of slow and quick-acting types, the former, for instance, being regulated by a wattmeter relay from the effective component of supply to the main machine v or by hand, and the latter by any quick-acting regulator. The Specification, as open to inspection under Sect. 91 (3) (a), comprises also the form shown in Fig. 5 (Cancelled), in which the quick-acting device is made as a purely electrically-operating regulator in the form of a " Danielson " converter u. The synchronous generator e, having two field windings w<1>, w<2> placed in quadrature, excites the commutator machine k. The winding w<1>, which regulates the effective component, .s connected to a continuous-current network n<2> and is adjusted by a slow-acting regulator r<1>. The winding w<2>, which regulates the wattless component, is connected to the continuous supply through the commutator of the converter driven from the alternating network n<1> through a transformer t. The machines e, u, together with the continuous-current generator p, are driven by a synchronous motor in having the same polenumber as the " Danialson " converter. The brushes of the converter are so set that its armature flux is proportional to the wattless component of the network current and opposed to that of the field winding w<3>. Thus. at a given network power factor the fluxes balance and the converter gives no volts while departure from this power factor causes the winding w<2> to aid or oppose the excitation due to w<1> in proportion to the wattless current component. This subjectmatter does not appear in the Specification as accepted.