US1379560A - Protective device for incandescent lamps - Google Patents

Description

C. A. B. HALVORSON, In, PROTECTlVE DEVICE FORTNCANDESCENT LAMPS.

APPLICATION Huu' ocr. 26,1916.

PatentedMay 24 1921i.

25 IT) vencor:

Cromwell $1.13. Hal VOTSOT) J17,

His ttomeg.

warren stares HUSETTS, ASSIGNOR 1'0 GENERAL ELECTRIC COMEANY, A CORPORATION 03 NEVJ YQRK.

PROTECTIVE DEVICE FOR INCANDESCENT LAMIPS.

awrence.

Application filed October 26, 1916.

To all whom it may concern:

Be it known that T, CRoMwELL A. B. HAL- VORSON, J11, a citizen of the United States, residing at Lynn, county of Essex, State of lllassachusetts, have invented certain new and useful Improvements in Protective Devices for Incandescent Lamps, of which the following is a specification.

My present invention relates to protective devices and cut-outs for incandescent lamps, and more particularly for use with such lamps when operated on direct current series circuits.

When incandescent lamps are operated on series circuits, in case the filament of one lamp on the circuit burns out or becomes broken or for any reason duringthe operation of the lamp there is a tendency for an arc to rorm which may assume such proportions as to cause the lamp to explode, or in case the lamp is burned with the tip downward it may move along the leading-in wires and cause fusing oi' the lamp socket. As soon as the arc becomes extinguished, unless the lamp is short-circuited, the continuity of the circuit is broken and all of the lamps on the circuit become dead.

The object of my invention is to overcome the above difficulties and provide a device whereby the continuity of the circuit will not be broken when the filament of any lamp on the circuit becomes broken for any reason. A further object of my invention is to provide a device which will offer protection to the lamp from abnormal conditions occurring in the circuit to which it is connected.

In carrying my invention into effect I provide one of my improved devices for each lamp on the circuit. The device in its general characteristics comprises a coil which is in series with the lamp and a second coil which is in shunt to the lamp. A resistance is also provided which is in shunt to the lamp when the lamp is not burning. W hen the current starts to flow in the circuit the series coil operates a contact to open-circuit the resistance so that the main current will all flow through the lamp except for a small amount carried by the shunt coil. In case the filament of the lamp becomes broken the momentary rise in voltage across the lamp is suilicient to cause the shunt coil to operate and close a contact which throws the resistance in shunt to the lamp and allows the main current to flow through the resistance.

Specification of Letters Fatent.

Patented May 24:, 1921. Serial no. 127,812.

ds soon as this occurs the potential across the lamp 1s decreased and any are which may be Iormed in the lamp is extinguished. as soon as the current through the lamp is interrup ed the contact operated by the series coil again closes the circuit throu h the shunt resistance. b

The features of my invention which I consider novel are polntedout with particun the appended claims, the invention itseir, however, both as to its mode of operatlon and organization will best be understood by reference to the following description taken in connection with the accompanying drawing in which Figure l is a view partly in section and partly in elevat on of one or my devices; Fig. 2 is a plan view of the same; F 3 is an elevation of thpOltlOl'l or the device as seen from line XXpr" Fig. l; Fig. l is a plan view of a portion of the device as seen along the line TY of Fig. l; and 5 is a diagram showmg the method oi connecting my device to a lamp.

{as shown in the drawing my device comprises a series coil 1 and a shunt coil 2 supported by a frame-work 3. The core d of the series coil carries at its lower end a contact member 5. l v hen the lamp is not in operation the contact 5 rests upon a stationary contact member 6 which is supported from the frame-work 3 by means of a bracket 7 fastened to the frame-work b means of the screws 8. The contact 6 is held directly by a clamp 9 which is supported from the bracket '7 but insulated therefrom by means of the insulating members The core ll of the shunt coil 2 acts upon the pivoted armature 12 which carries the contact member 13. A resistance 1% has one erminal connected to the lamp terminal 15 and the other terminal is connected to the stationary contact member 6 by means of binding post 16 which is fastened to the clamp 9 The normal position of the different parts when the lamp is not in operation is indicated diagrammatically in Fig. 5. It will be seen that there are two paths through the device through which current from the line conductors 17 and 17 may flow. One of these paths is through the lamp 18 and the series coil 1, the other through resistance 14, contact members 6 and contact member 5. There is in addition a shunt path through the shunt C011 2.

, to cause this coil to operate and attract its.

When current starts to flow through the line conductors 17, 17, the current will divide, part of it going through the lamp and series coil, part through the resistance 14: and a very small amount through the shunt coil 2. Thereupon the series coil 1 will operate and cause contact members 5' and 6 to separate, thereby cutting out resistance 141 and causing the main current to flow through the lamp. The shunt coil 2 is so proportioned and its core 11 so adjusted that it will not attract the armature 12 unless the potential across the coil is somewhat greater than the normal operating voltage of thelamp. It now the filament of the lamp should become ruptured there would be a momentary rise in voltage across the lamp terminals and across coil 2 suificient armature, thus causing contact 13 to close upon contact 6 again connecting the resistance in shunt to the lamp. As soon as this happens the potential across the lamp will fall, the value of resistance 14: being much less than the normal resistance of the lamp. Thus any arc which might form in the lamp will at once be extinguished and the current through the lamp interrupted. As a result core 41 will be released allowing contacts 5 and 6 to come together and thus furnish a path for current through the resistance, at the same time that armature 12 is released by reason of the drop in voltage at the terminals of coil 2.

In order to render the device suitable for operation with lamps having different voltage ratings, I have provided a special means for adjusting the core of the shunt coil 2 whereby the device may be quickly adapted to be used with lamps of different voltages. The upper end of the core 2 is provided with screw threads and is held in place by means of a nut 19 which is furnished with an indicating pointer 20. The initial adjustment of the device may be carried out by means of the nut 19 and also by means of the screw stop 21 by which the position of the armature 12 may be determined. f the adjustment is made so that the device operates properly with lamps of normal operating voltage it may be so arranged that the pointer 20 is turned for example to the scale marking 22, then if the particular lamp which is to be used with the device happens to have a voltage rating slightly above or below the normal operating voltage, by turning the nut 19 to the right or left toward scale markings 23 or 24:, the device may be quickly adjusted so that its operation will be correct for the particular lamp which is to be used. When the proper adjustment has once been made the core may be held in position by tightening the thumb nut 25; It will of course be understood that the scale markings 22, 23 and 2 1 may be given any convenient designation to enable the one who changes the lamps to readily tell at a glance the exact point to which the pointer 20 should be moved, it being assumed that the lamp which is placed'in the fixture is marked with its proper voltage rating.

If for any reason there should be a rise in current in the circuit above the normal operating current the voltage across the shunt coil will rise and cause it to close the contact 13 upon contact 6, thus allowing the main current to flow through the resistance and thus protect the lamp from burning out.

While I have illustrated a single embodiment of my invention, it will be apparent that many modifications in the structural details as well as in the exact method of connection, may be made without departing from the scope o1 my invention as set forth in the'appended claims.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. The combination with an incandescent lamp of a coil in series therewith, a coil in shunt to said lamp and said series coil, a resistance, a movable contact member operated by each of said coils and a stationary contact member which cooperates with both of the movable contact members to throw the resistance in shunt to the lamp and the series coil, the parts being so arranged and proportioned that in the normal operation of the lamp both movable contact members will be out of contact with the stationary contact member, when the lamp is open circuited the member operated by the series coil will be in contact with the stationary member and when the voltage across the lamp rises above a predetermined value the member operated by the shunt coil will be in contact with the stationary member.

2. The combination with an incandescent lamp of a coil in series therewith, a coil in shunt to the lamp and the series coil, a movable contact member operated by each of said coils, and a resistance the parts being so arranged and proportioned that when the lamp is not in operation the resistance will be in shunt with the lamp and the series coil, when current starts to flow in the lamp the resistance wil be open circuited by the contact member operated by the series coil, and whenthe voltage across the lamp rises above a predetermined value the resistance will be thrown in shunt with the larfip and the series coil by the contact member operated by the shunt coil.

3. The combination with an incandescent lamp of a coil in series therewith, a coil in shunt to the lamp and'the'series coil, a resistance and contact members controlled by said coils, the parts being so proportioned and arranged that when the lamp is'not in operation the resistance will be in shunt to the lamp and the series coil during the normal operation of the lamp the resistance will be open circuited and when the voltage across the lamp exceeds a predetermined value the resistance will be thrown in shunt with the lamp and the series coil.

4. A protective device for incandescent lamps comprising a coil adapted to be connected in series with a lamp, a coil adapted to be connected in shunt to the lamp and the series coil, a resistance, a movable contact member operated by each of said coils, and a stationary contact member which cooperates with both of said movable contact members the parts being so arranged and proportioned that when the series coil alone is energized both movable members will be out of contact with the stationary member, when the shunt coil alone is energized both movable members will be in contact with the stationary member, and when both coils are energized the movable member controlled by the shunt coil will be in contact with the stationary member, and the other movable member will be out of contact with the stationary member, and when either movable member is in contact with the stationary member the resistance will be in shunt to the shunt coil.

5. A protective device for incandescent lamps comprising a coil adapted to be connected in series with a lamp, a coil adapted to be connected in shunt to the lamp and the series coil, a. resistance adapted to be connected in shunt to the lamp and series coil, a movable contact member operated by each of said coils, and a stationary contact member which cooperates with both of said movable contact members the parts being so arranged and proportioned that when the series coil alone is energized both movable members will be out of contact with the stationary member, when the shunt coil alone is energized both movable members will be in contact with the stationary member, and

' when both coils are energized the movable member controlled by the shunt coil will be in contact with the stationary member, and the other movable member will be out or" contact with the stationary member, and when either movable member is in contact with the stationary member the resistance will be in shunt to the shunt coil, the shunt coil being so proportioned that it will be operatively energized only when the Voltage applied thereto exceeds a predetermined desired amount and being provided with means for adjusting it to operate at the desired voltage.

6. lhe combination with an incandescent lamp of a coil in series therewith, a coil in shunt to the lamp and the series coil, a movable contact member operated by each of said coils, a stationary contact member and a resistance, the parts being so arranged and proportioned that in the normal operation of the lamp both movable contact members will be out of contact with the stationary contact member and the resistance open circuited, when the lamp is open circuited the member operated by the series coil will be in contact with the stationary member and the resistance in circuit and when the voltage across the lamp rises above a predetermined value the member operated by the shunt coil will be in contact with the stationary member and the resistance in circuit.

7. The combination with an incandescent lamp of a coil in series therewith, a coil in shunt to the lamp and the series coil, a movable contact member operated by each of said coils, a stationary contact member and a resistance having one terminal connected to said stationary contact member and the other terminal connected to a lamp terminal, said movable contact members being connected to a terminal of the series coil, the parts being so arranged and proportioned that in the normal operation of the lamp both movable contact members will be out of contact with the stationary contact member, when the lamp is open circuited the member operated by the series coil will be in contact with the stationary member and when the voltage across the lamp rises above a predetermined value the member operated by the shunt coil will be in contact with the stationary member.

In witness whereof, I have hereunto set my hand this 24th day of October, 1916.

CROMWELL A. B. HALVORSON, Jr.

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