US724072A

US724072A - Alternating-current arc-lamp.

Info

Publication number: US724072A
Application number: US9789902A
Authority: US
Inventors: Thomas Edgar Adams
Original assignee: Individual
Current assignee: Individual
Priority date: 1902-03-12
Filing date: 1902-03-12
Publication date: 1903-03-31
Anticipated expiration: 1920-03-31

Description

PATENTED MAR. 31, 1903.

T. E. ADAMSL ALTERNATING CURRENT ARC LAMP.

APPLICATION FILED MAR. 12, 1902.

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No. 724,072. PATE'NTED MAR. 31, 1903.

T. B. ADAMS.

ALTERNATING CURRENT ARC LAMP.

' APPLICATION FILED MAR. 12, 1902.

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PATENTED MAR. 31, 1903'.

T. E. ADAMS. ALTERNATING CURRENT ARC LAMP.

APPLICATION FILED MAR. 12' 1902.

3 SHEETS-SHEET 3.

K0 MODEL.

UNITED STATES PATENT OFFICE.

THOMAS EDGAR ADAMS, OF CLEVELAND, OHIO.

ALTERNATIN G-CURRENT ARC-LAM P.

.IEECIFICATION forming part of Letters Patent No. 724,072, dated March 31, 1903.

. Application filed March 12, 1902. Serial No. 97,899. (No model.)

. To all whom it may concern:

Be it known that I, THOMAS EDGAR ADAMS, a resident of Cleveland, in the county of Ouyahoga and State of Ohio, have invented certain new and useful Improvements in Alternating-Current Electric-Arc Lamps; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as willenable others skilled in the art to which it appertains to make and use the same. H

Myinvention relates to an improvement in electric-arc lamps, and more particularly to the shunt type adapted for use in serie on alternating-current circuits. 7

One object of the invention isto produce a lamp of this type having electromagnetsinstead of solenoids, whereby less turns of wire are necessary on the spools to overcome the reluctance of the shorter air-gaps A further object is to utilize in 'analterhating-current shunt-series lamp a spool;

having other duties to perform, as a'weight to separate the carbons.

A further object is to so construct a lamp of the character above specified in which the shunt-circuit is the onlyeleotric path through the lamp at the starting thereof that a very slight rise above normal of the currentin the shunt will close a second or safety electric path through the lamp before either the carbon or cut-out paths are closed.

A further object is to so construct the regulating mechanism of a shunt-lamp that at starting a choke-coil will be made to operate to prevent excessive rising of the initial curl rent.

A further object is to so construct the regulating mechanism of a shunt-lamp. that a coarse-wire coil willbe promptly thrown in parallel with the shunt-coil when the initial current enters the lamp.

A further object is to so construct the regulating mechanism of a shunt-lamp that the shunt-magnet will promptly operate to close a switch and include a coarse-wire magnetcoil in parallel with said shunt-magnet.

A further object is to so arrange the parts of the regulating mechanism that a coarsewire magnet in the safety-path will hold said path closed after the shunt-spool has closed it until either the carbon or cut-out paths are closed.

closed either the coarse-wire magnet in the safety-circuit will act to close the other and hold both switches closed until the carbons are brought together or the current ceases.

A further object is to so construct a passage or duct in depending portion 31 of the inner-globe cover that air entering shall become expanded and interrupt a free current of air entering the inner or arc-inclosing globe.

A further object is to reduce to a minimum thefriction of the carbon in its guideways and at the same time to so arrange the clutch as to bind the carbon sufficiently to prevent vibration appearing in the arc.

. With these objects in view the invention consists in combinations and arrangements of features hereinafter descrihed,and pointed out in the claims.

In the accompanying drawings, Figure 1 is a view of a lamp embodying my improvements. Fig. 2 is a plan view with the cap removed. Figs. 3, 4, and 5 are enlarged views of the regulator mechanism. 8 are detail views illustrating the arc-inclosing-globe cover and carbon-guide Fig. 9 is a diagram of the circuits.

1 represents the lam p-casing, made, preferv ably, of sheet metal and provided at its upper end with'a ring2, having afiange 3 on its top. Thelower portion of the sheet-metal casing is made flaring and has secured therefin' a basin 4., preferably of cast metal, which constitutes the floor of ,the lamp. A reflector 5'is secured to the bottom of the basin .4 and also constitutes a cover for the outer globe 6, which latter is retained normally in The place by means of a suitable-holder.

basin or lamp-floor 4 and reflector 5 are provided with central openings to permit the passage of the upper carbon and portions of the clutch-operating devices, and at respective sides of said central openings arms or hangers 9 depend from the basin or lamp- Fig. 10 is a detail view of the inner-globe support.

Figs. 6, 7, and

floor 4. To the lower end of the hangers 9 a horizontally-disposed frame 10 is secured by means of screws 11, and each of these screws is provided with an eye for the attachment of a yoke 12, having a conical coiled spring 13 at its lower end for pressing the arc-inclosing globe 14 upwardly against its cover, as more fully hereinafter explained. The frame 10 is provided with a hollow boss 15, in which the upper end of an insulating-sleeve 16 is inserted, the lower end of said sleeve passing through a hole in the inner-globe cover 17, and the intermediate portion of the sleeve 16 is provided with a flange or collar 18, disposed between the frame 10 and cover 17. The upper end of a rod 19 is passed through the sleeve 16 and insulated thereby from the globe-cover; but said rod is electrically connected with the frame 10 by means of a rivet passing through the integral boss on the frame and through the said rod 19. The rod 19 depends to a point near the bottom of the inner globe 14, where it is provided with a holder 20 for the lower carbon 21 of the lamp. The frame 10 (with which the rod 19 is electrically connected) is itself electrically connected with one of the hangers 9, and the latter is electrically connected with the upper leaf 22 of a cut-out or short-eircuiting switch 23. The said upper leaf of the short-circuiting switch is connected with a binding-post 24 in the lamp-casing by means of a wire 25, and said binding-post is connected bya wire 26 with the negative terminal of the lamp.

The frame 10, hereinbefore referred to, also serves to support the inner-globe cover 17, for which purpose the said frame is made with a series of perforations for the passage of screws 27, which enter lugs 28 upon the globe-cover 17, said lugs serving to space the cover 17 a short distance below the frame 10. The screws 27 are insulated from the frame 10 by suitable washers 29, and the frame 10 is insulated from the globe-cover 17 by means of washers 30. The globe-cover 17 is provided at a point in \vardly removed from its periphery with a hollow depending annular portion 31, which enters the open upper end of the arc-inclosing globe, and the shoulder 32 at the upper end of said depending annular portion is ground smooth to form a seat for the upper end of the globe, the conical spring 13 at the lower end of the yoke 12 serving to press the upper edge of the globe firmly but yieldingly against said seat. globe-cover is provided with a large central opening 33, and around this opening the cover is made with a flange 34, which rises slightly above the top face of the cover and is preferably ground smooth to serve as a seat for a tubular cap 35. The cap 35 is provided with a ground seat 36, which rests upon the seat 34 on the cover 17, and located within the inner boundary of the seat 36 is an annular flange 37, which depends loosely into the opening 33 in the cover and provided in its exterior wall with a series of notches 38.

The top of the I series of lugs 39 project outwardly from the cap 35 and are disposed beneath the insulating-washers 30 for the purpose of limiting the upward movement ofsaid cap. The cap 35 is also provided with a lateral enlargement 40, which serves as a stop for the clutch, hereinafter referred to. The upper carbon 41 of the lamp passes downwardly through the cap 35, and the latter is provided interiorly with a series 0f annular grooves or ducts 42, so that air entering the same shall become expanded and interrupt a free current of air entering the arc-inclosing globe. Should the gas-pressure within the arc-inclosing globe become excessive, such pressure would cause the cap to rise a limited distance and permit the notches 38 to become ducts through which the gas can escape. As soon as the pressure is thus relieved the cap 35 will again become seated.

The hollow depending portion 31, above referred to, is made with a depression 99 to accommodate the supporting-rod of the lowercarbon holder, and the depression 99 also serves to interrupt the duct formed in the depending portion 31. An inlet 101 for cold air communicates with one end of the duct 100, and hot air can enter the globe from the other end of said duct through a port 102. Pins or rivets 103 are passed at intervals through the duct 100 and serve to obstruct said duct, forming it into several expansionchambers. The duct 100, composed of several expansion-chambers, being located in the portion 31, depending into the globe, will be in the hotter air or gas in the globe and will be more effectual than a duct in the cover per 86. Cold air entering the duct 100 will become expanded in the expansion-chambers composing said duct, and thus interrupt a free current of'air entering the arc-inclosing globe.

A clutch-ring 43 is located between the frame 10 and the lamp-floor, and this ring is so disposed as to tend to bind the upper carbon against its guides for the purpose of holding the carbon steady, and thus preventing the appearance of vibration in the are. It is important, however, that friction between the carbon and its guides shall be reduced to a minimum, so as not to interfere in the slightest in the proper movement of the carbon. I therefore provide within the lampcase a strut 44, against which the lifting-hook bears and against which it is pressed laterally by the lifting-rod, said rod tending to press the carbon laterally. The strut 44 comprises three

parts

44, 44 and 44 The part 44 is preferably of copper and is pivotally 'attached to the clutch-lifter, and the part 44 is preferably of steel and pointed at one end to have a pivotal bearing in a socket in the basin 4. The part 44 of the strut is made of mica or other insulating material and serves to connect the

metallic parts

44 and 44.

A slotted tube 46 is secured'centrally with in the lamp-casing and receives the upper carcelain clutch-ring 43.

bon t1 and its holder. A binding-post 47 is secured to the upper-carbon holder and projects out through the slot in the tube 46 for the reception of one end of a flexible conductor 48, the other end of which is attached to a binding-post 49 within the lamp-casing, and said binding-post is connected with the positive terminal of the lamp by means of a conductor 50.

The upper end of the carbon-guide 46 has secured thereto an air-pot 51, and the latter is provided on its top with a cylindrical extension 52, which receives a plunger depending from the cap 53 of the lamp-casing, and thus the upper end of the carbon-tube is held properly in place,

The clutch-ring 4.3, which, as before stated, is located between the lampfloor and the frame 10, which supports the inner-globe cover, is preferably made of porcelain and is held in a light frame 54, preferably of sheet metal. A clutch lifter 55, passing down-- wardly through the lamp-floor, is pivoted near its lower end to the frame 54 and is provided at its lower extremity with a hook or tooth 56 to engage the inner face of the por- The lifter being con nected with the clutch at the periphery of the latter, it is apparent that when said lifter is raised the clutch will not only grasp the carbon rod, but will also tend to press the lower portion of same laterally against the guide-roller, as before mentioned. Thelifter 55 ismade with a tubular portion through which a rod 57 passes, the lower end of said rod resting on the metal frame 54 of the clutch-ring 43 and the upper end of said rod being connected with the plunger in the airpot 51.

A frame 58 is mounted on the ring 3 at the upper end of the lamp-casing and comprises end plates 59, having lips 60 to engage the flange 3 of said ring, and U-shaped yokes 61 62, connecting said end plates at each end of the latter, one of said yokes depending into the lamp-casing and the other projecting upwardly into the cap 53. A brace 63 is secured at its ends to the plates 59 and between its ends to the depending yoke 61. The yokes 61 62 each consist of a series of iron plates secured together, and thus constitute laminated armatures for electromagnets 63 64, each having laminated cores projecting beyond the ends of the coils to form pole-pieces 65 66 to become disposed between the parallel arms of the respective yoke-armatures. The magnet 63 is wound with fine wire, and the magnet 64 is wound with coarse wire and connected up in thelamp-circuit, as explained farther on. The magnets are disposed horizontally parallel with each other and spaced apart by spring-metal plates 67, the ends of which are secured to the pole-pieces of the magnets, permitting perpendicular but resisting lateral displacement. This elasticity reduces noise and loosening of pa'rtsincident to use of alternating currents.

A bar 68 is secured at its ends to the under faces of the respective plates 67 at points nearer the fine than the coarse wire magnet, and the intermediate portion of this bar is bent laterally toward the coarse-wire magnet 64. At each end the under face of the bar 68 is made-with V-shaped grooves 69 for the reception of knife-edges 70, secured to the end plates 59 of the frame 58, and thus the spring-plates 67 and bar 68 constitute a lever carrying the magnets and is pivotally supported upon the knife-edges on frame 58, so that the coarsewire magnet Will overbalance thefine-wire magnet. In order to prevent longitudinal displacement of the trunnion-bar 68 and the magnets, screws 71 are inserted in said bar and engage the ends of the knife-edge plates 70. The bar 68 is held properly on the knifeedges, and the parts carried by said bar are retained in place by means of thumb-pieces 72, pivoted to the frame 58 and adapted to overhang the trunnion-bar. Blocks 73 are secured to the pole-pieces of the fine-wire magnet, and to these blocks a yoke 74 is pivotally connected. A red 75, having weights 75 thereon, is attached to (and preferably insulated from) the yoke 74, and the lower end of said rod is provided with a hook 76, which engages the clutch-lifter.

The carbons are included in a circuit traced in the diagram by the conductors 5O 48 77 25 26, and the fine-wire magnet is included in a shunt-circuit traced on the diagram by the conductors 50 78 79 80 81 26. The carbons are normally separated when no current is passing, so that when current enters the lamp the great resistance of the carbon-circuit will cause the current to traverse the shunt-circuit and energize the fine-wire magnet 63,

with the result of tipping the frame 58 on its knife-edge bearings against the weight of the coarse-wire magnet, and thus lower the clutch.- lifter and clutch until the latter engages the enlargement on the frame 10 over the innerglobe cover, and thus cause the clutch-ring to be tilted, so as to permit the upper carbon to feed freely through itand fall into contact with the lower carbon. As soon as this occurs the resistance of the carbon circuit will be decreased below that of theshunt-circuit, and hence the fine-wire magnetwill decrease in strength and the weight of the coarse-wire magnet will act to tilt the frame 58, raise the fine-wire magnet, and through the rod 75, lifter 55, and clutch-ring 4:3 establish the arc. While the carbons in the lamps of the shunt type on an alternating-current constantotential circuitare apart at starting, the pressure has to force enough current through the shunt of all the lamps to start them. The resistance of the shunts in series keeps the current down until as the carbons come together and the resistance is diminished the current rises, and the last lamp to get its carbons together is apt to have its shunt burned up. To avoid such a result as this, I providea safety device,which will now be ex IIC . magnetic parts.

plained. A diagonally-disposed lever 82 is pivoted between its ends to the fulcrum-bar 68 under one of the spring-plates and provided at its respective ends with laminated armatures S3 84, the armature 83 being in position to be actuated by one of the pole-pieces of the fine-Wire magnet and the armature 84 being so disposed as to be actuated by one of the pole-pieces of the coarse-wire magnet. A contact-point 85 is secured to but insulated from one of the spring-plates, and another contact-point 86 is secured to and insulated from the lever 82, these parts thus constituting a switch, (shown at 87 in the diagram Fig. 9.) The lower end of the switch -lever 82 is heaver than the upper, and therefore the contacts 85 86 are normally separated when no current is passing through the lamp. The contact-point 85 is connected by the wire 80 with one terminal of the fine-wire magnet and by wires 81 26 with the negative terminal of the lamp. The contact-point 86 of the switch 87 is connected by conductors SS 89 90 with one terminal of the coarse-wire magnet 64, and the other terminal of this magnet is connected with the conductors 78 79 by a wire 91. From this construction and arrangement of parts and circuits it will be readily seen that initially-viz., when no current is passing through the lamp-the coarse wire magnet will bein an open circuit in parallel with the shunt-circuit, which includes the fine-Wire coil, and this multiple-arc circuit, including the coarse-wire magnet, may be conveniently termed a utility or safety path or circuit through the lamp. When current first enters the lamp, it will traverse the shunt-circuit, as before explained, and energizing the fine-wire magnet will cause the latter to actuate the lever of switch 87 and immediately close the utility or safety circuit and thus throw the coarse-wire magnetin parallel with the fine-wire magnet. It Will be remembered that my lamp is constructed and intended for use principally with an alternating current, the changes necessary for constant-potential direct current being merely to wind the shunt of finer wire to prevent overheating and obtain economy. Neither is it necessary, though permissible,tolaminate the When the coarse-wire magnet is included in parallel with the fine-wire magnet on an alternating circuit, it will not short-circuit the latter, but the coarse-wire magnet will cooperate with its armature to set up a counter electromotive force in its coil, and thus produce an effective choke-coil, and at the same time it will move in unison with the shunt-coil to feed the carbon or failing in that to cut out the lamp. The lever of the safetyswitch 87 has small inertia and a very short distance to travel and its movements are not interfered with by an air-pot nor subject to change of a spring. Therefore it acts practically instantaneously when current enters the lamp to throw the coarse-wire magnet in parallel with the shunt-magnet, and by the teams choking elfect of said magnet the sudden rise of current when the carbons of the various lamps of the series are brought into contact will be choked su'lficiently to materially assist any regulator that may be in series with these lamps and to prevent the burning out of the shunt-coil of the lamp whose carbons are the last to come together. It is also apparent that the multiple effect of the coarsewire magnet will prevent undue heating of the shunt-coil of each lamp of the series. The coarse-wire magnet is thrown in so quickly by the switch 87 and its choking eifect so prompt that the initial current rise in the system is not excessive in any case. The features of the utility path or circuit are of great advantage in the practical operation of the system. -The regulator is permitted thereby to work with a very light dash-pot, and usually no dash-pot at all is necessary. The combined quick effect of lamp and regulator spools prevents enormous strain to all insulation, and when the operator closes the circuit the system starts smoothly and without apparent shock.

n order to provide an automatic cut-out in case of the breaking of either carbon or the sticking or non-feeding of the upper carbon, the devices now to be described are employed. Contact-springs 92 93 are attached to the respective spring-plates 67 at the ends of the coarse-wire magnet-spool 64, and contactarms 94 95 are secured to (but insulated from) theupperarmature-yoke62. Thecontact-arms 94 95 are connected with each other bya wire 96, and they are connected with the negative terminal of the lamp by the

wires

97 and 26. The contact-springs 92 93 are connected with each other by the conductor 89 and with the lever of the safety-switch 87 by the Wire 88. The two pairs of contacts 92 94 and 93 95 therefore constitute two cut-out switches arranged in parallel with each other. Now should the resistance of the carbon-circuit abnormally increase on account of the breaking of a carbon or the refusal of the upper carbon to feed a sufficient amount of current would flow through the shunt-magnet to cause it to move down to the full extent of its throw, and thus cause the contacts 92 94 to come together, or should the increase in strength of shunt be spasmodic the safety or utility path would be closed and the coarse-wire magnet would then act to assist the shunt or independently feed the carbon or cut out the lamp. The meeting of the contacts 92 94 will serve to partially shortcircuit or cut out the fine-Wire shunt-magnet, but the coarse-wire magnet will still be in circuit and sufficiently strong to bend the spring-plates and to bring the other cut-out contacts 93 95 together and hold all the said cut-out contacts together to short-circuit the shunt-coil until the carbon is caused to feed or the current ceases to flow through the lamp. Should contacts 93 95 be the first to come together, contacts 92 94 would be closed afterward with certainty, because the coarsewire magnet has abundant strength to bend spring supporting-plates. The lamp is therefore well guarded with cut -onts, for even starting with no carbons in the lamp the safety-circuit closing immediately permits the lamp to come to cut-out position easily, the safety-switch 87 closing no matter where the coarse-wire spool is in relation to the cutout contacts. When shunt closes the safety path, the coarse wire will feed the carbon or cut out the lamp, assisting the shunt or doing it independently.

The entire lamp can be cut out or shortcircuited by means of the switch 23, one leaf of this switch being connected with the positive terminal of the lamp by wires 98 50 and with the negative terminal of the lamp by wires 25 26.

Having fully described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. The combination in an arc-lamp, of a pivoted lever, a clutch, an electromagnet having a fixed core mounted on one end of said lever and included in a shunt-circuit, a fixed armature for said magnet a weight on the other end of said lever, and a mechanical connection between said shunt-magnet and clutch.

2. The combination in an arc-lamp, of a lever pivoted between its ends, a clutch, a finewire magnet having a fixed core on one end of said lever and included in a shunt-circuit, a mechanical connection between said shuntmagnet and clutch to feed the upper carbon down, a coarse-wire magnet on the other end of said lever to overbalance the finewire magnet when the carbons come together, fixed armatures for said magnets and a shuntcircuit including said coarse-wire magnet.

3. An'alternating-current electric-arc lamp comprising carbons, a clutch, two circuits shunting the carbons and in parallel with each other, a fine-wire magnet included in one of said shunt-circuits and connected with the clutch and a choke-coil included in the other shunt-circuit.

4. The combination in an alternating-current electric-arc lamp, of a shunt-magnet, a choke-coil in aninitially-open parallel circuit and means for closing the circuit of the chokecoil.

5. The combination in an alternating-current arc-lamp, of a shunt regulator-magnet, and a choke-coil in a parallel circuit controlled by said shunt-magnet.

6. The combination in an alternating-current arc-lamp of a shunt regulator-magnet, a choke-coil in parallel with said magnet, an initially-open switch in series with the chokecoil and means for closing said switch.

7. The combination in an alternating-current arc-lamp, of a shunt regulator-magnet, a choke-coil, a switch, a circuit in parallel with the shunt including said choke coil and switch, and an armature on said switch actuated by a pole-piece of the shunt-magnet to close said switch.

8. The combination in an alternating-current arc-lamp of a shunt regulator-magnet, and a choke-coil in parallel with and under the control of the sh nut-magnet.

9. The combination in an alternating-current arc-lamp, of two circuits which shunt the carbons, a fine-wire regulator-magnet in one of said circuits and a coarse-wire magnet in the other, an armature for each of said magnets, and devices cooperating with said magnets for regulating and controlling the operation of the lamp.

10. The combination in an alternating-current arc-lamp, of two circuits which shunt the carbons, said circuits arranged in parallel with each other, a regulator-magnetin one of said circuits and a coarse-wire magnet inthe other, armatures for said magnets, and devices cooperating with said magnets for regulating and controlling the operation of the lamp.

11. The combination in an alternating-cur rent arc-lamp, of two circuits which shunt the carbons, one of which is initially open, a regulator-magnet in the other circuit, a chokecoil in the initially-open circuit, and means for closing said open circuit.

12. The combination in an alternating-current arc-lamp, of two circuits arranged in parallel with each other and both shunting the carbons, of a regulator-magnet in one of said circuits, a choke-coil and a switch in the other, and means actuated by the regulatormagnet for closing said switch.

13. The combination in an alternating-current arc-lamp, of a high-resistance magnet and a low-resistance magnet arranged in parallel with each other and both in shunt with the carbons, armatures for said magnets, and devices cooperating with said magnets for controlling the operation of the lamp.

14. The combination in an alternating-current arc-lamp, of a high-resistance regulatormagnet shunting the carbons, a low-resistance magnet in parallel with the high-resistance magnet and also shunting the carbons, and a switch in series with the low-resistance magnet and arranged to be actuated by both to close the circuit of said low-resistance magnet.

15. The combination in an alternating-current arc-lamp, of an electromagnet in a circuit shunting the carbons, a choke-coil in parallel with said magnet, a switch in series with the choke-coil, and an armature on said switch in position to be actuated by the shuntmagnet to close the circuit including the choke-coil.

16. In an alternating-current arc-lamp, the combination with a lever pivotally supported between its ends, of a high-resistance magnet on one end of said lever and included in a shunt-circuit, a low-resistance magnet on the other end of said lever and included in parallel with the shunt-magnet, armatures for said magnets, a switch carried by said lever and included in series with thelow-resistance magnet and means for closing said switch when the shunt-magnet is energized.

17. In an alternating-current arc-lamp, the combination with a lever pivoted between its ends, of a fine-wire magnet on one end of said lever, a coarse-wire magnet on the other end of said lever, armatures for said magnets, a circuit shunting the carbons and including the fine-wire magnet, a circuit in parallel with said fine-wire shunt-magnet and including the coarse-wire magnet, a switch in said parallel circuit, means cooperating with the shunt-magnet for closing said switch, and means cooperating with the coarse-wire magnet for keeping said switch closed.

18. In an alternating-current arc-lamp, the combination with a lever pivoted between its ends and a clutch connected with one end of said lever, fine-wire magnet on the end of the lever with which the clutch is connected and included in a circuit shunting the carbons, a choke-coil on the other end of the lever and normally overbalancing the fine-wire coil said choke included in parallel with the finewire coil.

19. In an alternating-current arc-lamp, the combination with a pivoted lever-and a clutch connected with one end thereof, of a shuntcoil on the end of the lever with which the clutch is connected, a choke-coil on the other end of the lever, said choke-coil normally overbalancing the shunt-coil and included in parallel therewith, a switch carried by said lever and included in series with the chokecoil, and means actuated by the shunt-magnet for closing said switch.

20. In an alternating-current arc-lamp the combination with a lever pivoted between its ends and a clutch connected with one end of said lever, of a fine-wire magnet on the end of the lever with which the clutch is connected and included in a circuit shunting the carbons, a coarse-wire magnet on the other end of saidlever and mechanically overbalancing the fine-wire magnet, said coarse-wire magnet included in parallel with the fine-wire magnet, armatures for said magnets, a switchlever pivoted between its ends to said pivoted lever and carrying a contact-point, another contact-point carried by the pivoted lever, said contact-points included in series with the coarse-wire magnet, and an armature on each end of said lever adapted to be actuated by the respective magnets.

21. In an alternating-current arc-lamp, the

combination with a fine-wire regulator-mag not included in a circuit shunting the carbons, a coarse-wire magnet included in parallel with the fine-wire magnet, a switch included in series with the coarse-wire magnet and comprising a pivoted lever and codperating contacts, said lever weighted at one end to maintain the contacts normally separated, and armatures at respective ends of said switch-lever to be actuated by the re spective magnets.

22. In an arc-lamp, the combination with a lever pivoted between its ends, of a regula- .tormagnet secured to one end of the lever included in a circuit shunting the carbons, a clutch connected with said lever, a weight at the other end of the lever and a cut-out switch normally open at the weighted end of the lever.

23. In an alternating-current arc-lamp, the combination with a pivoted lever, of a regulator-magnet carried by one end thereof, a clutch connected therewith, an armature for said magnet, a coarse-wire magnet carried by the other end of the lever and included parallel with the regulator-magnet, an armature for the coarse-wire magnet and a cut-out switch cooperating with the end of the lever carrying the coarse-wire magnet for shortcircuiting the regulator-magnet.

24. In an alternating-current arc-lamp, the combination with a pivoted lever and a clutch connected therewith, of a fine-wire magnet carried by one end of said lever and included in a circuit shunting the carbons, a coarsewire magnet carried by the other end of the lever and mechanically overbalancing the fine-wire magnet, said coarse-wire magnet included in parallel with the fine-wire magnet, two switches for short-circuiting the finewire magnet arranged in parallel with each other, one of said switches adapted to be closed by the fine-wire magnet and the other closed and both maintained closed by the action of the coarse-wire magnet after the fine- .wire magnet has been short-circuited.

25. In an alternating-current arc-lamp, the combination with a pivoted lever, of a shuntregulator magnet carried by one end of the lever, a fixed armature therefor, a coarsewire magnet carried by the other end of the lever and included in parallel with the shuntmagnet, an armature for the coarse-wire magnet, contact-arms attached to the lever and connected in series with said parallel circuit, and contact-arms attached to the armature of the coarse-wire magnet and included in with each other and in series with the lampterminals, said contact-arms cooperating to form two cut-out switches in parallel for short-circuiting the shunt-regulator magnet.

26. In an arc-lamp, the combination with the cover of the inner globe havinga central hole therein, of a tubular cap entering said hole and resting on the cover, said cap having external notches where it enters the hole in the cap.

27. In an arc-lamp, the combination with the cover of the inner globe having a central hole therein, of a tubular cap entering said hole and resting upon the cover, the portion of the cap entering said hole having external notches therein, and the interior of said cap having annular grooves.

28. In an arc-lamp, the combination with a clutch for theupper carbon, guides for the latter, and a clutch-lifter connected with the clutch, of means connected with said lifter for reducing friction of the carbon in its guides.

29. In an arc-lamp, the combination with the carbon, of aguide for the carbon, a clutch engaging the carbon and a device tending to press it against said guide, and means connected with said device for reducing friction of the carbon against its guide.

30. In an alternatingcurrent electricarc lamp,the combination with a spring-lever pivotallysupported between its ends, of magnets secured to the ends ofsaid spring-lever, armatures forsaid magnets,a clutch connected with said lever and two electric circuits arranged in parallel and including respectively said magnets.

31. In an arc-lamp, the combination with a spring-lever pivoted between its ends and a regulator-magnet carried by one end of said spring-lever and a clutch connected with said lever, of a weight on the other end of said spring-lever, and a cut-out switch comprising a stationary contact, and a contact carried by the weighted end of the lever.

32. In an arc-lamp, the combination with a spring-lever pivotally supported between its ends and a fine-wire regulator-magnetcarried by one end of said spring-lever, of a coarsewire magnet secured to the other end of said spring-leverand included in a circuit in parallel with the fine-wire magnet, a clutch connected with said lever and a cut-out switch comprising two sets of contacts, one set of said contacts secured to a stationary support and the other set attached to the end of the spring-lever to which the coarse-wire magnet is secured.

33. In an arc-lamp, the combination with a guide for the upper carbon, and a clutch tending to press the carbon toward said guide, of a truss for reducing friction of the carbon against its guide.

34. In an arc-lamp, the combination with a casing, a clutch and a clutch-lifter, of a truss pivoted at one end to the clutch-lifter and at the other end to the casing.

35. In an arc-lamp, the combination with a casing, a clutch and a clutch-lifter, of a truss pivoted at one end to the clutch-lifter and at the other end to the casing, said truss comprising two metallic end sections and an intermediate section of insulating material.

36. In an arc-lamp, the combination with a regulator-magnet, and a coarse-wire magnet included in parallel shunt-circuits, of an elastic support for the coarsewire magnet, a clutch connected with the regulator-magnet and a cut-out switch comprising two sets of contacts,one set carried by a fixed support and the other set carried by the coarse-wire magnet for cutting out the regulator-magnet.

37. The combination in an arc-lamp, of a lever, knife-edge pivotal supports for the lever, a clutch, an electromagnet having a fixed core mounted on one end of said lever and included in a shunt-circuit, a fixed armature for said magnet, a weight on the other end of said lever and a mechanical connection between said shunt-magnet and clutch.

38. In an electric-arc lamp,the combination.

with a globe and a cover, of a device supported by the cover and projecting down into the globe, said device having a hot-air duo therein.

39. In an electric-arc lamp,the combination with'the' globe and the cover therefor, of a device supported by the cover and depending down into the globe, said depending device having a hot-air duct therein composed of a series of communicating expansion-chambers, one end of said duct open to the external air and the other end opening into the globe.

In testimony whereof I have signed this specification in the presence of two subscribing witnesses.

THOMAS EDGAR ADAMS.

Witnesses:

JOHN D. ERTEL, O. J. CRABLE.