Patent GB-107777-A (GB)
Title: Improvements in and relating to Electric Current Regulators, more particularly for use with Arc Lamps.
IPC: H05B31/00
Filed: 1916-04-13
Abstract: 107,777. Marks, E. C. R., (Goldberg, H.). April 13, 1916, Arc lamps.-Apparatus for regulating a lamp for projection, photography, &c., comprises an electrically - actuated make - and - break switch having one coil in series with the device, and another coil in parallel with an operating-solenoid in a shunt circuit controlled by the switch. In the make-and-break electro-magnet, shown in Fig. 1, the series and shunt coils 11, 12 are wound one within the other about a core 15 projecting beyond both end plates 16 of the coil bobbin. An armature 18 pivoted to a bracket 19 on the upper end plate is attached to a retractile spring 20, adjustable by means of a flexible connector 21 wound about a screw 22 provided with a lock-nut 23. An insulating plate 29 prevents contact between the core and armature. An adjustable upper stop 25 is provided for the armature, which carries a contact strip 26, normally separated from an adjustable contact 27 so that the shunt circuit is open. When current falls below the minimum allowed, the armature is released and the shunt circuit closed: the shunt coil then assists the series coil and the shunt circuit is re-opened. Ordinarily one such current impulse causes a sufficient approach of the electrodes, but otherwise the action is repeated. In the shunt circuit is a switch which comprises a gravity-controlled armature 30 below the make-and-break magnet and is open when no current flows through the lamp. The electrodes must therefore be operated by hand at starting and the risk of their being left in contact is diminished. The solenoid 50, Fig. 2, is designed so as to act more quickly than the shunt coil of the make-and-break electro-magnet, with which it is connected in parallel. The solenoidcore is linked to an arm 53 raised by a bent spring 52 and moving between adjustable stops 75, 75a. Pivoted to the arm 53 is a spring- urged pawl 70 driving a ratchet-wheel 55. A brake spring 72 holds the ratchet-wheel during the return of the pawl. An adjustable screw 74 disengages the pawl from the wheel 55 when the arm 53 rests against the upper stop 75, leaving the mechanism free for hand actuation. The hub of the ratchet-wheel is secured to a sleeve which slides without relative rotation on a shaft, a groove in the shaft being engaged by a setscrew passing through the sleeve and a surrounding collar. A pinion gearing with racks on the electrode-holders is driven by the shaft through a universal joint. A hand-wheel 64 is attached to the outer end of the sleeve. The above apparatus may be employed alone or in conjunction with another regulator for separating the electrodes when current is too large. In the second regulator, the make-and-break magnet is wound differentially, and the upper armature is normally held up by the spring with the shunt circuit open. This make-and-break magnet has no lower armature; the lower armature of the first magnet also may be omitted or may be held up by the screw stop so that it cannot open the shunt circuit. Separate and oppositely-acting solenoids, pawls, and ratchet-wheels are provided, arranged as described above, Three hand switches are placed in the shunt circuits so that either regulator, or both simultaneously, can be thrown out of action.