Patent GB-190704031-A (GB)
Title: Improvements in or relating to Alternate Current Motors.
Inventor: FYNN VALERE ALFRED
Filed: 1907-02-18
Granted: 1908-02-18
Abstract: 4031. Fynn, V. A. Feb. 18. Motors, alternating-current ; field magnets.-In an induction motor of the split-phase type fed from a single-phase supply or from one phase of a polyphase supply and having inducing windings displaced in space with respect to each other, the electromotive force impressed upon one or more of the inducing windings has at least two components, one or more of which are derived from a phase-displaying circuit, connected to the supply and comprising elements of differing impedence. One or more of the inducing windings may form part of a phase-displacing circuit. In the arrangement shown in Fig. 7, the phase-displacing circuit 1, 2, 3, connected to the mains, includes the inducing winding S' and a capacity C or an ohmic resistance, the electromotive force at the terminals of the winding S' being impressed through a transformer T upon the circuit of the winding S<2>, which is also connected to the mains either directly or through a transformer. The phase displacements to be brought about by the capacity C can be reduced by making the magnetizing-current of the transformer T large, for example, by using a hedgehog transformer, by increasing its magnetic density, or by introducing an air gap, or by connecting a reactance in parallel with the secondary winding of the transformer T or the winding S<1>. The transformer T can be dispensed with by connecting in the circuit of the winding S<2> an auxiliary field winding in transformer relation to the winding S', or a part of the winding S<1> may be used for the purpose. In modifications, the electromotive force at the terminals of the capacity C or resistance may be impressed upon the circuit 4, 5. 6 through a transformer, such as T, a capacity being connected in parallel with either the transformer secondary or the winding S<2>. In a modified arrangement, both electromotive forces impressed upon the winding S<2> may be derived from the circuit 1, 2, 3, and a third electromotive force, for example that of the main, may also be impressed upon the winding S<2>. Both windings S', s<2> may form part of phase-displacing circuits, Fig. 12, in inductive relationship. In the example shown in Fig. 13, the circuit 1, 2, 3 is connected to the mains through the auto-transformer T and regulator K<1>, and three electromotive forces, derived as shown, are impressed upon the winding S<2>. The capacity C of the arrangement shown in Fig. 7 may be replaced by a reactance, and a capacity may be connected in parallel with the winding S', or it may be connected across the terminals of an auxiliary stator winding co-axial with the winding S', or the auxiliary winding may be closed on itself or on resistance, reactance, or capacity, and may be in inductive relation to both windings S', S'. A modification is described in which three windings angularly displaced by 120 degrees are each supplied with two electromotive forces, one from the mains and the other from a phase-displacing circuit. The mutual induction between the windings S', S<2> and the induced member may differ in some known manner, for example, by making the axial or peripheral span, or both, of one inducing winding different from the corresponding spans of another winding ; or the reactance of the induced member may be made small along the axis of one inducing winding and large along the axis of another inducing winding. To vary the speed, both members of the motor may be wound for different numbers of poles, and two stators with a common rotor, as described in Specification No. 4170, A.D. 1894, may be used. The condensers are constructed on the lines of a galvanic or secondary cell, Figs. 17 and 18, and consist of plates of aluminium, or iron and aluminium alternately, immersed in a solution of soda. These cells are connected in series, or series - parallel, as required. According to the Provisional Specification, the arrangements above described may be applied for improving the commutation or power factor of alternate-current motors.