Patent GB-190502172-A (GB)
Title: Improvements in or relating to Electric Traction Systems.
Inventor: BOULT WILFRID SWANWICK
Filed: 1905-02-03
Granted: 1906-02-01
Abstract: 2172. Boult, W. S. Feb. 3. Electric railways and tramways on the trans-' former or induction system of collecting energy in which the primary sectional coils or conductors are placed in a shallow slot conduit and the secondary coil or collector, carried by the car and connected in circuit with the car motors, runs therein. Conductors ; switches; collectors ; conduits.-The primary coils A, shown diagrammatically in Fig. 1, are connected in series and shunted by a lowresistance shunt B through switches C which are operated mechanically by the collector H, carried by the car, so as to throw the corresponding coils A into circuit as the car passes. Figs. 2, 3, and 4 show a plan, side elevation, and end elevation, respectively, of a conduit with the switches and collector in position ; Fig. 5 shows a transverse section of the conduit at another point, the primary and secondary coils being shown. The upper portion of the conduit is formed by the usual slot rails E, on which run special wheels F, secured to the car and carrying the collector. The collector consists of secondary coils G wound on laminated magnetic cores G<1> fixed in a frame H jointed at H<1> so that the collector can adapt itself to curves in the track. The cores G<1> have enlarged ends cooperating with the polar surfaces of the troughs A', and the sections of the secondary coils are separately connected for controlling purposes. The switches C are opened, during the passage of the collector in either direction, by the arm C', which projects into the conduit, being pushed on one side. The arm C<1> controls the switch C through the link connexion shown, and is restored to its normal position by the springs C' when the collector has passed. The primary coils A, which are of considerable length, are laid in iron troughs A' so as almost to surround the secondary coils. The arrangement, as shown in Fig. 5, comprises two primary coils, which may be connected either in series or in parallel, with a secondary coil G between them. The secondary coils are protected from wet and mud by the pans H<2>, the conduit slot is kept clear by the sloping faces F<2> of the plates F<1>, and any dirt or stones which collect in the conduit are swept into boxes or pits by the scraper J. In a modified arrangement, the wires forming one side of the coil A are laid in an iron trough at one side of the conduit, and the corresponding wires forming the other side are placed in another trough on the opposite side of the conduit, the ends of the coils being sunk below the level of the troughs in order to leave a clear passage for the collector. Modified arrangements are shown in Figs. 8 and 9 for extending the distance between the operating-switches to any desired length. The switch shown in Fig. 8 is thrown over alternately to one contact and the other as the car passes either way, and is suitable for a line where only one car is intended to be between the switches at at one time. Fig. 9 shows an arrangement for dealing with any number of cars, not exceeding five, on the section at one time. Where large numbers of cars pass, the switching and shunting arrangements may be abolished. The system, it is stated, is intended for use with alternating or interrupted currents and is particularly suited to the constant-current supply system. The Provisional Specification also states that the core G<1> may be shaped, in section, like a trident, the centre prong carrying the secondary winding and the outer prongs embracing the primary winding.