Patent GB-190304969-A (GB)
Title: Improvements in Electric Arc Lamps.
Inventor: ADAMS THOMAS EDGAR
Filed: 1903-03-03
Granted: 1903-06-18
Abstract: 4969. Adams, T. E. March 3. Arc lamps.-An enclosed-arc clutch lamp, especially for use in a series constant-pressure alternating- current circuit, is regulated by a shunt electromagnet, with which a second shunt electromagnet co-operates immediately on starting the lamp, The frame of the lamp consists of a cover 53, a casing 1, a cast metal base 4, two side rods (not shown) on this base, a plate 10, and a rod carrying the lower carbon-holder 20 within an arc-enclosing globe 14. This globe is held up to a cover 17 by a spring 13, in a yoke attached to the side rods. The cover 17 is carried by insulators on the plate 10. An outer globe 6 is carried by a reflector 5 on the base 4. The upper carbon slides in a central tube 46, which is attached to a dashpot 51, and held by a rod in the hood 53. The clutch consists of a porcelain ring in a metal holder 54, which is connected by two links 55, 75 to an arm 74 of a regulating-lever 67. The lower link 55 is guided by a non-conducting link 44, swinging in the base 4. The lever 67 consists of parallel spring plates carried by a crosspiece on knife-edges attached to a ring 2, projections on which prevent displacement of the lever ; screws on the lever prevent displacement of it along the knife-edges. The springy ends of the lever 67 carry two straight electromagnets 63, 64 with laminated iron cores, which can move between the ends of two curved laminated-iron armatures 61, 62, fixed on the ring 2. The magnet coil 63 is of fine wire, connected permanently between the terminals of the lamp, and acts to rock the lever 67 in opposition to the overbalancing weight of the other electromagnet 64, the clutch 54 being thus lowered, as usual, in a shunt lamp. A switch lever 82, pivoted on the ring 2, carries laminated iron cores respectively above and under the cores of the electromagnets 63, 64 at one end ; either magnet when excited holds the switch lever in opposition to gravity so that a contact on it bears against another on the regulating lever 67, and connects the magnet coil 64 between the terminals of the lamp. The coil 64 is of coarse wire, and acts as a choking coil shunting the pressure coil 63, the coil 63 being thus protected against excessive pressure. Two springs on the regulating-lever 67 touch two stationary contacts 93 if the regulating-lever is moved further than usual, by excessive pressure on the coils 63, 64 ; these contacts make the same connections as the switch lever 82, and act as a cut-out. The clutch 54 is in contact with a rod 57 attached to the piston of the dash-pot 51. The clutch-releasing stop is formed on a gas-check 35, which fits in a hole in the inner globe cover 17, and has a shoulder to rest on this ; the periphery of the gas-check below the shoulder is grooved vertically to allow escape of gas if the gas-check is lifted by excessive pressure in the globe 14. The globe cover 17 has a circular conduit 31 depending in the globe 14, so as to become hot ; the opposite ends of the conduit open into the globe 14 and to the outer air, and the conduit is obstructed by transverse pins at intervals, to impede passage of air.