Patent GB-190407662-A (GB)
Title: Improvements in Electric Arc Lamps
Inventor: CAROLAN EDGAR ALFRED
Filed: 1904-03-31
Granted: 1905-02-16
Abstract: 7662. Carolan, E. A., [General Eleetric Co.]. March 31. Arc lamps.-A lamp having one electrode of a material which gives a flaming arc, and the other electrode of a non-consuming material such as copper, is started by means of an auxiliary electrode adapted to make contact with the flame electrode. A lamp with a brake regulating mechanism is described, in which the shunt regulating- coils are provided with a series resistance. T h i s resistance is normally short-circuited, but devices are provided to open the short-circuit when the lamp is cut out of circuit or fails to operate. Depending from the base-plate 1 are tubes 5, 6, united by a crosspiece 7 and by an insulated bridge 8. In the bridge 8 is a tubular part 9, from which extends a tubular non-consuming electrode 10, preferably of wrought copper, which may form one piece with the parts 9, 8, but is preferably detachable for renewal. The bridge 8 also carries a cylinder 8<1> of sheet metal, such as copper, to cool the electrode. Above and below the bridge 8 respectively are sliding cross-pieces 11, 12. One end of the piece 11 and the opposite end of the piece 12 are rigidly attached, through slots in the tubes 5, 6, to guiderods 13, 14 within the tubes; the other end of each cross-piece is forked to embrace the tube. The cross-piece 11 carries a heavy insulated weight 15 and a rod 16 supporting the holder 17 of the auxiliary electrode 18, and the cross-piece 12 carries the holder 19 of the electrode 20, which is formed of or contains titanium carbide or other substance giving a flaming arc. A conductor 21 connects the cross-piece 12 to a cage 22 consisting of annular discs 23 united by vertical pieces 24. The cage 22 is secured by insulating-clamps to the tubes 5, 6, and its function is to steady the arc by the action of the current in the bars 24. To brackets 26, attached to the plate 1, is pivoted a frame 25, consisting of two parallel plates. A sprocket-wheel 28, mounted to turn in the frame 25, is connected by suitable gear-wheels to a brake-wheel 32, on the shaft of which is also a fan to retard its motion. A shaft 34, also pivoted in the frame, carries a brake shoe 33 and an arm 35. A spring 36, attached to the frame and to the arm 35, holds the shoe 33 in contact with the brakewheel 32, except when the arm strikes a thumbscrew 38 mounted in a post projecting from the bracket 26. An arm 46 is rigidly attached to the frame 25 and pivoted to a yoke-piece 47, of magnetic material, which connects a pair of magnetic cores 48 having conical ends. Each of these cores moves in a pair of coils 50, 51, the latter coils being mounted on the plate 1 and having each an inner tubular shell of non-magnetic material, which enters into and forms a support for the corresponding coil 50 above it. The shells also form guides for the cores 48, and are slotted to admit the yoke 47. The rocking of the frame 25, by the action of the series solenoids 50, is resisted by a spring 42 attached to the frame and to a collar 41 adjustable on a post 40, and is limited by the engagement of a stop 52 on the frame with the plate 1. Over the sprocket-wheel 28, and through apertures in the plate 1, passes a chain 53, one end of which is attached to the weight 15 and the other to the rod 14. The wheel 28 is so placed with regard to the pivots on which the frame 25 turns that, when the cores 48 are raised by the series solenoids 50, the auxiliary electrode 18 is raised by a much smaller distance than that by which the electrode is lowered. The arc, struck by the electrode 18, is transferred to the electrode 10, when the electrode 18 is drawn up into it. The electrode 18 is proportioned so as to consume, due to the feeding, rather slower than the electrode 20 does in the maintenance of the arc ; if the electrode 18 becomes too long, the arc burns it away to the right length before passing to the electrode 10. A post 55, extending up from the plate 1, carries two insulated flexible arms 56, 57, having on them studs which normally rest in contact and shortcircuit a non-inductive resistance 54. This resistance and the two coils 51 in series form a shunt-circuit between the cage 22 and one of the terminals of the lamp, which is connected to the electrode 10, the other terminal being connected through the series coils 50 to the cage 22. A pin 59 in the frame 25 lifts the upper arm 56 and opens the short-circuit when the upper carbon 18 is lowered, and a rod 60 is provided, which passes through the clamp supporting the cage 22, and is offset to prevent it from falling right through the clamp. When raised a certain distance, the bridge 12 engages the end of the rod 60 and lifts the contact-arm 56. The lamp is supported by a pulley or other means, attached to a yoke 3 pivoted on arms 2 fixed to the plate 1. The casing 75 is supported by means of yokes 76, which hook over lugs 77 on the plate 1. Ventilation is afforded by holes 79 near the bottom and holes 81 near the top. The former holes are shielded by a hood 80, and the casing is surrounded by an annular member 82, which may form a continuation of the hood, and is provided with holes 83, opposite the holes 81, and shielded by a second hood 84. The globe 85 is closed below by a dish 87, spaces being left, if desired, between the globe and the dish for ventilation.