Title:
Time relay for fluorescent lamps
United States Patent 2286800


Abstract:
The present invention relates to gaseous electric discharge lamps particularly of the positive column cold-hot electrode type and has special reference to starting and operating circuits for such lamps. Lamps of this general type are now well known to the art and in order for such lamps to...



Inventors:
Gustin, Daniel S.
Application Number:
US32689240A
Publication Date:
06/16/1942
Filing Date:
03/30/1940
Assignee:
WESTINGHOUSE ELECTRIC & MFG CO
Primary Class:
International Classes:
H05B41/10
View Patent Images:



Description:

The present invention relates to gaseous electric discharge lamps particularly of the positive column cold-hot electrode type and has special reference to starting and operating circuits for such lamps.

Lamps of this general type are now well known to the art and in order for such lamps to be operated from the usual source of commercial potential of 115-230 volts, it is customary to employ an inductance element which, upon the occurrence of certain conditions, causes a high voltage surge to be impressed across the electrodes of the lamp to initiate a discharge, after which the operating voltage decreases to a value sufficient to be sustained by the voltage of the commercial source.

It has also been proposed in the prior art to provide a choke which supplies the high voltage surge and which limits the operating current with the choke opening and closing a pair of contact members upon the flow of electrical energy through the choke. Such contacts, however, have heretofore been operative in the atmosphere and, being affected by atmospheric conditions, cause very erratic operation of the switch as well as deterioration of the contact members.

It is accordingly the primary object of the .esent invention to provide a starting and operating circuit for a gaseous discharge lamp wherein an inductance element is employed which causes movement of a pair of contact members upon the flow of electrical energy therethrough and which inductance element is in no way affected by atmospheric conditions...

Another object of the present invention is the provision of a starting and operating circuit for a gaseous discharge lamp wherein an integral inductance and switching device having a pair of magnetizable contacts enclosed within an evacuated container is utilized for initially connecting the inductance element to the source and in electrical parallel with the discharge lamp, which contacts are opened upon the flow of electrical energy through the winding of the inductance to cause a high voltage surge to be impressed' across the electrodes of. the discharge lamp and the winding of the inductance element to be in series relationship wi'h the lamp and source.

Another object of the present invention is the provision of a unitary switch and inductance element wherein a pair of magnetizable contacts are enclosed within an evacuated container and which serve as a core for an inductance winding bsrrounding the evacuated container with the contacts being movable upon the flow of electrical energy through the winding of the inductance element.

Still further objects of the present invention will become obvious to those skilled in the art by reference to the accompanying drawing wherein: Fig. 1 is a diagrammatic illustration of a starting and operating circuit for a gaseous discharge lamp in accordance with the present invention, and Fig. 2 is a cross-sectional view of the novel inductance element of the present invention as used in the circuit shown in Fig. 1.

Referring now to the drawing in detail, there is shown in Fig. 1 a gaseous electric discharge lamp 5 which after evacuation is provided with an ionizable medium, such as a few drops of mercury, together with a rare gas such as argon, neon, or helium to facilitate starting. Disposed at each end of the lamp 5 are electrodes 6 and 7 which are of the type commonly referred to in the art as the cold-hot type. In other words, the electrodes are of suitable metal which when heated produces a copious flow of electrons, or they may be.of the activated type wherein the metal is coated 'with a material which emits a Scopious flow of electrons..

- As is well known, electrodes of this type are not heated from an exterior source, but are heat') ed solely by the heat generated by the discharge.

The electrode 7 is connected by a conductor 8 to one side L-I of a suitable source of supply of the usual commercial potential of 115-230 volts. In a sirhilar manner the electrode 6 is '" connected by means of a conductor 9 and the winding. 0 of an inductance element 12 and an additional inductance or resis'or 13 to the opposite side of the commercial source of supply L-2.

As shown more clearly in Fig. 2, the inductance 41) 12 is provided with a core comprising an evacuated container 14 which is provided with a pair of normally closed refractory metal contacts 15 and 16 supported by magnetizable metal s'rips 17 and 18, such for example as iron. Thus the '5 contacts 15 and 16 are hermetically sealed from the atmosphere so that dlimatic conditions in no way impair the operation of the contacts; and inasmuch as the container is evacuated, arcing between the contacts is substantially eliminated. By reference again to Fig. 1, it will be noted that the contact terminal 15 is connected by means of a conductor 19 to the conductor 9 and thus to the electrode 6 and one end of the winding 10 of the inductance element 12. Similarly the contact terminal 16 is connected by means of a conductor 20 to the conductor 8 and thus to the remaining electrode 7 of the lamp 5 and one side of the source of supply L--.

Due to the circuit arrangement thus described, it mwill be noted that two parallel circuits are thus formed, one circuit extending from the source of supply L-I through the conductors 8 and 20, the contacts 16 and 15, conductors 19 and 9, inductance winding 10, and an additional inductance or resistor 13 bafk to the opposite Sside of the source of supply L-2, while the other circuit extends from the sour. L-I- through ';he conductor 8 to the electrode, 7 of the lamp and thence from the electrode 6 through the conductor 9, inductance 12 and resistor 13 back to the opposite side of the source of supply L-2.

Thus the effect of operation of the contacts 15 and 16 is to short-circuit the lamp 5.

Accordingly, upon closure of a suitable switch (not shown) current will flow through the first circuit above described since the contact terminals 15 and 16 are initially closed. However, inasmuch as the resistance of the lamp 5 is initially exceptionally high and it is in effect short-circuited', no current flows through the parallel circuit including the lamp 5. When the current flows through the winding 10 of the inductance element 12, the magnetic flux generated thereby causes opening of the magnetizable contacts 15 and 16.

This interruption of the circuit causes a high voltage surge from the winding 10 of the inductance element 12 which is impressed between the electrodes 6 and 7, and since this voltage is substantially higher than that available from the source L-I, L-2, the resistance of the lamp 5 is broken down and a discharge will be initiated between the electrodes 6 and 7. This discharge accordingly ionizes the gas within the lamp 5 and the heat generated by the discharge heats the electrodes 6 and 7 to a temperature sufficient to produce a copious flow of electrodes which sustains the discharge.

During continuance.of the discharge, the inductance element 12 together with the additional inductance or resistor 13 serves to limit current supplied to the lamp 5. Also, as the current continually flows through the winding 10 of the inductance during operation of the lamp 5, the magnetic flux generated thereby maintains the contact terminals 15 and 16 in an open position.

Thus the inductance 12 is connected in a series circuit with the lamp 5 and upon opening of the contacts 15 and 16, the short-circuit condition of the lamp 5, which initially exists, is eliminated for the purposes of starting the lamp 5.

It thus becomes obvious to those skilled in the art that a starting and operating circuit for a gaseous discharge lamp is herein provided wherein an integral inductance and switching, device is provided having contacts which form the switch enclosed within an evacuated container so as to be shielded from the atmosphere and are thus unaffected by climatic conditions.

Moreover, the evacuated container for the contact terminals forms a core for the inductance element, the winding of which surrounds the vitreous envelope.

Although one specific embodiment of the present invention has been shown and described; other modifications thereof may be made without departing from the spirit and scope of the appended claims.

I claim: 1. The combination of a gaseous electric discharge lamp provided with electrodes therein between which a discharge occurs upon the application of electrical energy thereto, a source of electrical energy for energizing said lamp, and an inductance element having its winding connected to said source and to one of the electrodes of said.lamp, said inductance being wound upon a core constituting a pair of normally closed magnetizable contacts enclosed in an evacuated container, one of which is connected to one end of the winding of said inductance for initially short-circuiting said lamp and operable upon the flow of current through said inductance to eliminate the short-circuit condition of said lamp and to cause a high voltage starting surge to be supplied by said inductance to said lamp and said contacts to be maintained in an open position during operation of said lamp by the flow of current through said inductance.

2. A starting and operating circuit for a gaseous electric discharge lamp provided with electrodes which support. a discharge when heated conmprising a source of electrical energy for energizing said lamp, an inductance element having its winding connected to said source and one of the electrodes of said lamp, and said inductance element being wound upon a core constituting an evacuated container provided with a pair of normally closed magnetizable contacts shielded from the atmosphere, one of which is connected to one end of said inductance winding for initially short-circuiting said lamp and operable. upon current flow through said inductance to eliminate the short-circuit condition of said lamp and to simultaneously cause a high voltage starting surge to be supplied by said inductance to said lamp and said contacts to be maintained in an open position during operation of said lamp by current flow through said inductance.

3. The combination with a gaseous electric discharge lamp provided with electrodes which support a discharge when heated, of a starting circuit for said lamp comprising an inductance element provided with a winding having one of its ends connected to a source of electrical energy and being wound upon a core constituting an evacuated container provided with a pair of normally closed magnetizable contacts therein shielded from the atmosphere, one of said contacts being connected to the other end of the inductance winding and to one of the electrodes of said lamp and the other of said contacts being connected to said source and to the other electrode of said lamp whereby said contacts initially effect a short-circuit of said lamp; an operating circuit for said discharge lamp comprising the electrodes of the latter, the inductance winding and said source; and said inductance being operable upon the flow of current through said 60 winding to cause separation of said contacts and elimination of the short-circuit of said lamp with an attendant voltage surge from said inductance across the electrodes of said lamp and the energization of said operating circuit. DANIEL S. GUSTIN.