Patent GB-190613585-A (GB)
Title: Apparatus for Enabling the Transformation of a Single-phase Alternating Current into a Continuous Current.
Inventor: AUVERT LOUIS RENE
Filed: 1906-06-13
Granted: 1907-05-16
Abstract: 13,585. Auvert, L. R., and Ferrand, A. F. E. July 3, 1905, [date applied for under Patents Act, 1901]. Converting alternating and direct currents.-A machine for converting a single - phase alternating current into an undulating continuous current comprises a laminated iron ring a, Fig. 1, driven by a synchronous motor, and carrying two sets of reversely-wound coils b, c and b<1>, c<1> connected to separate commutators d, d<1>, on which bear stationary brushes k, l. Each commutator has two wide segments g, h and g<1>, h<1> connected to slip-rings i, j and i<1>, j<1> for the introduction of the single-phase current, and eight narrow segments f, f<1> connected to turns of the windings b, c and b<1>, c<1>. The slip-rings are preferably connected to the secondary windings of two static transformers supplied from the same source. The brushes k, l are connected in series. An even number of sets of brushes may be used upon each commutator, by proportionately increasing the number of windings upon the ring, the brushes of the same polarity being connected in parallel so as to form two groups. The continuouscurrent voltage is varied by shifting one or both sets of brushes round the commutator The winding is preferably built up of half turns m, Fig. 4, and whole turns n soldered together at the ends o, p, which are connected to the commutator segments d by short and long connecting-strips o<1>, p<1> of high-resistance material, to improve the commutation. The connexions p<1> consist of horizontal and vertical strips soldered together. The horizontal strips are supported on the periphery of the ring a, Fig. 5, between the turns of the winding, and the soldered ends o, p of the latter are carried upon rings q fastened to the clamping-members for the core laminµ, and are secured by hooping. The pairs of slip-rings i, j and i<1>, j<1> may be arranged upon their respective commutators ; or all four may be secured upon the periphery of the ring a, or at the ends of the shaft outside the bearings. In the last case, the connexions between the slip-rings and the commutators are carried inside the shaft, which is hollow. The converter may be directly employed for traction purposes, to convert the alternating current supplied to the vehicle into continuous current for feeding the motors. To double the voltage, two converters are employed in series, Fig. 6. The brushes on the commutators d, d<1>, d<2>, d<3> are connected in series with the motors r, and the corresponding slip-rings are fed from alternating - current mains through transformers t', t<2>, t<3>, t', the primary windings of which are either arranged in series or in parallel. The continuous current may be made less undulating by placing inductance s in the motor circuit. When the motors have laminated series-wound field magnets, the coil s may be dispensed with. The motors are controlled by shifting some or all of the sets of converter brushes, and may be converted into generators to brake the vehicle and to restore alternating current to the mains.