US965139A - Starting device for arc-lamps. - Google Patents

Description

G. M. LITTLE. STARTING DEVICE FOR ARC LAMPS Patented July 19, 1910.

APPLICATION FILED SEPT.3,1907.

WITNESSES:

A'TTORNEY UNITED STAElEtl lite/Edith o it "w r n-"av 1 T GEORGE M. LITTLE, OF PITTSBURG, PENNSYLVANIA, ASSIG'NOR TO XVES'IINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

STARTING DEVICE FOR ARC-LAMPS.

Specification of Letters Patent.

Patented July 19, 1910,

Application filed September 3, 1907. Serial No. 391,239.

To all whom it may concern:

Be it known that I, GEORGE M. LITTLE, a citizen of the United States, and a resident of Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented new and useful Improvement in Starting Devices for Arc-Lamps, of which the following is a specification.

My invention relates to arc lamps and particularly to lamps in which insulating fumes or bodies of slag sometimes deposit or form upon the electrode and interfere with ready starting of the arc.

The object of my invention is to provide simple, reliable and inexpensive means for causing movement of the electrodes of arc lamps into and out of engagement for the purpose of removing the slag and fumes that deposit thereon. I

Are lamps are now frequently provided with electrodes containing materials that render the same less readily consumable than ordinary carbons and that also insure the production of arcs of greater luminosity than those produced by ordinary carbons, one suitable composition for securing these results comprising the magnetic oxid of ii-oi'1'(l e,,() as the prcdominent constituent, which gives conductivity to the electrodes both when hot and when cold, chromium oxid 10,), which, by reason of its very high fusing point, assists in preventing rapid consumption ot the electrodes and flickering of the arc, and titanium oXid (TiO or some other compound of titanium, which imparts color and brilliancy to the arc and also assists in prolonging the life of the electrode. In the use of electrodes having the above specified composition, bodies of insulating slag, composed largely of non-conducting oxids, sometimes form uponthem and thus prevent good electrical contact when they are brought into engagement for the purpose of starting the arc.

In order to insure suiiiciently good electrical contact between the electrodes to permit of ready starting of the arc, it has been proposed to remove the slag from the ends of the electrodes by causing rapid movement thereof into and out of engagement until the arc is established. The means that have herctotore been provided for eii'ecting this result have been complicated and expensive and have embodied parts requiring accurate adjustment, such, for instance, as dash pots or other retarding devices, thus increasing the first cost as well as the cost of maintenance.

The present invention provides a device of extreme simplicity that requires no adjustment or attention after having been installed in a lamp. and is exceptionally eti ectivc and reliable in operation.

Figure 1, of the accompanying drawings, is a perspective view of a portion of a lamp that embodies my invention. Fig. 2 is a view, partially in side elevation and partially in section, of certain of the. parts shown in Fig. 1, and Fig. 3 is a diagrammatic view of the circuits of a lamp embodying my invention.

Electrodes 1 and 2 of an arc lamp, either or both of which may be composed of the oXids above specified, or other suitable materials, are maintained normally out of engagement by means of a ring clutch 3 that engages the electrode 1. The clutch 3 is pivoted to the-lower end of a rod 4: that is attached at its upper end to a U-shaped elec tro-magnet core'5 having a winding 6, the said parts being normally maintained in the position shown,.by means of a spring 7. One terminal of the winding 6 is connected to a switch member 8 that cooperates with another member 9, and is actuated by an clectro-magnet having a winding 10, the respective terminals of which are connected to the electrodes 1 and 2. The switch member 9 is connected to the terniinal 12 of the lamp, and is actuated by an electromagnet having a winding 11 that is included in the series with electrodes 1 and 2 between terminals 1.2 and 13 of the lamp.

Included in series with the winding 6 is a resistance 14 and a conductor or heating coil 15 of a switch device 16 that governs a. shunt to the winding 6, the resistance 1a and the winding 15. 'The switch device 16 comprises normallyseparated stationary and movable contact terminals 17 and 17, the terminal 1?? being mounted upon the upper free extremity of an actuating arm 18, the lower end of which is secured to a stationary plate or bracket 19. The arm 18 is coniposed of two strips or bodies 20 and 21 formed of materials, such, for example, as copper and iron, which have different coefficients of expansion when subjected to variations in temperature, and is subjected to varying degrees of temperature by the conductor or winding 15 which is here shown as surrounding it but insulated from it The conductor or winding 15 may, of course, be disposed or arranged in any other suitable manner with respect to the arm 18 so that, when current traverses said winding, the heat produced therein will be transferred to the arm. The arm 18 is provided with laterally projecting armature 22 that extends into the field produced by the electro-magnct winding 6.

When current is first supplied to the lamp, it traverses a circuit including the winding 15, the resistance 14, electro-magnet winding 6 and switch terminals 8 and 9that are normally in engagement. The magnet winding 6, being thus energized, causes the magnet core 5 to be drawn downwardly against the tension of the spring 7, and the electrode 1 is thereupon lowered into engagement with .the electrode 2. If a good electrical contact is established between the electrodes a circuit is completed from the lamp terminal 13 by way of magnet winding 11 and electrodes 2 and 1 to the terminal 12, and the switch terminal 9 will be raised out of engagement with the terminal 8 by the magnet winding 11. Separation of the switch members 8 and 9 interrupts the circuit of the magnet winding 6, and the. magnet core 5, together with the electrode 1, are raised by means of the spring 7, an arc being thereupon established between the electrodes 1 and 2. If, when the electrodes 1 and 2 are brought into engagement,'only an imperfect electrical contact is formed between them, the magnet winding 11 will not become suiiiciently energized to eifect separation of the switch terminals 8 and 9, and the circuit including devices'15, 14, 6, 8,-and 9 remains established. Continued passage of current through the coil 15 raises the temperature thereof, and in turn the temperature of the strips 20 and 21, which eX- pand unequally and cause the terminal 17 to move toward and into engagement with the stationary terminal 17 in opposition to the force of attraction exerted by the magnet winding 6 upon the armature 22. When the terminals 17 and 17 engage each other, the electro-magnet winding 6 is shunted and the armature 22 is released, so that the terminal 17 is pressed firmly into engagement with the terminal 17. The electrode 1 is also raised out of engagement with the and 17 come into engagement and the said coil, as well as the strips 20 and 21, are per causing the terminals 17 and 17 to separate more'widely. Thus, the cooperation of the armature 22 and the magnet winding 6 serves to cause firm engagement and quick separation of the terminals 17 and 17 and to prevent vibration of the arm 18.

Energization of the magnet winding 6 also causes the electrode 1 to again engage the electrode 2. The electrode 1 will thus be subjected to a continuous reciprocating movement until the slag or other insulating obstruction upon the electrodes is removed and a suiiiciently good electrical contact is established between the electrodes to permit ready starting of the are.

I claim as my invention:

1. In an arc lamp, the combination with electrodes, and means, comprising an electro-magnet winding, for moving the same into and out of engagement, of a switch for governing a shunt to the electro-magnet winding, and actuating means for the switch comprising rigidly connected bodies formed of materials having d-iiierent coefficients of expansion, a conductor located adjacent to:

the said bodies and connected in series with; the electro-magnet winding, and an arma-' t-ure carried by the-said switch and subject to the influence of said electro-magnet winding.

2. In an arc lamp, the combination with electrodes, and means, comprising an electro-magnet winding, for moving the same into and out of engagement, of a switch for governing a shunt to the electro-magnet winding, a thermostatic actuating device for the switch having a conductor in series with the electro-magnet winding, and an armature, carried by the said switch and subject to the influence of said electro-magnet winding.

In testimony whereof, I have hereunto GEORGE M. LITTLE.

Witnesses: 7

02cm S. SGHAIRER, Bnmnr HINES.

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