US2508337A - Starter for electric gaseous discharge device - Google Patents

Description

May 16, 1950 a. w. PEARCE STARTER FOR ELECTRIC GASEOUS DISCHARGE DEVICES Filed Aug. 15, 1946 I 2 Charge 3m earce mmvm 9 I BY ATTORNEY Patented May 16, 1950 UNIT D STATES: PATENT orrlos 2, 08,337 i y I s'raa'rsa roa ELECTRIC GASEOUS mscnaacs DEVICES George W. Pearce, Peabody, Mass mlgnor to T Sylvanla Electric Products Inc., Salem, Mass" a corporation of Massachusetta Application Alma: 13, has, Serial No. 600,242 2 Claims (Cl. 200-48) 1 invention relates to starters and more part ularly to starters for electric gaseous discharge devices such as fluorescent lamps.

An object of this invention is to provide a starter for electric gaseous discharge devices.

Another object' is to provide a starter for fluorescent lamps provided with filamentary electrodes.

A further object is to provide a starter for fluorescent lamps which will facilitate the initiation of the discharge across the lamp.

Further objects, advantages and features will be apparent from the following description when read in conjunction with the accompanying drawing in which: I

Figure l is an exploded view of the starter of my invention.

Figure 2 is a schematic drawing of the circuit thereof.

It has been the practice to provide fluorescent lamps with certain auxiliary equipment. One of these pieces of auxiliary equipment is a starter which operates to provide for the pre-heating of the filamentary electrodes of the lamp to electronemitting temperatures before the discharge across the lamp is initiated. Generally speaking these starters are usually of the glow or the thermal type. However, I have found that in many cases the electrode preheating period provided by many starters of the glow and thermal types is unnecessarily long. I have found that many fluorescent lamps may be started in a shorter period of time than many of the conventional glow and thermal starters will permit. The starter of my invention is considerably faster in its operation'thanthe conventional glow and thermal starters and thus enables one to start a fluorescent lamp in a shorter period of time.

The starter of my invention is a solenoidactuated one. It includes a current regulator of the glow lamp type adapted to pass enough ourrent to energize the solenoid and a cut-out which renders the starter inoperative after a reasonable number of attempts have been made to start the lamp and the lamp fails to light.

The starter of my invention comprises a body member I which may be moulded, for example, as shown in Figure 1, to provide for the seating therein of the several starter components. Compartrnents 2, 3 and! are provided in the body member I for the reception therein of a glow lamp 5, a solenoid 8 and a condenser 'I'respectively. The solenoid 6 is provided with an armature I. Seated above the solenoid t in the body member I and in register therewith is a pair of plates 2 and It. The adjacent faces of the plates l and II are each formed into a resilient spiral metal mesh II. Electrical contacts I 3 are centrally mounted on the resilient spiral metal meshes II. The top of plate It is provided with inwardly extending metal tabs I5, one end of each being connected to the periphery of the plate ,II, the other ends being free. A bimetallic cut-out member I6 is mounted on a shelf 26 provided therefor in the body member I directly above the plate It and normally engaged by the tabs I S thereon. A tab I1 is mounted in the bimetallic member It. When disposed and secured in the body member I the tab I'I extends through a slot I8 therefor in the body member. The body member I is also provided with a channel I! adapted to receive a base plate 20 to which base pins 2| are connected.

As mentioned above, the solenoid 6, the plates 9 and I0, and their resilient-spiral metal meshes II. and'the bimetallic cut-out member It are dis posed in the compartment 3. I have found it desirable to mount the plate 8 on top of the solenoid t which is supported on the shelf 23. The plate III is mounted on a shelf 24 so that it is normally insulated from and out of physical contact with the plate assembly 25. The bimetallic cut-out member I 6, which is mounted on shelf 26, is normally engaged by the metal tabs IS on top of plate I! but it is adapted, upon being excessively heated, to snap upwardly out of engagement withthe tabs I5.

Figure 2 shows the manner in which the several starter components are electrically connected. The starter may be employed in a conventional fluorescent lamp circuit, such as that shown in U.-S. Patent 2,195,115 for example, wherein a reactance coil is employed in the circuit to provide an inductive voltage surge to initiate a discharge across the lamp to start it and to ballast the lamp during operation. When a fluorescent lamp employing the starter of my invention is connected to a conventional -120 volt line, the glow lamp 8 will pass enough current to energize the solenoid 6. Energization of the solenoid 6 will actuate the armature 8 therein and cause the upper portion thereof to move upwardly through an aperture 22 in the solenoid 6 and engage the contact I 3 of plate 9. The contacts I2 on the adjacent faces of the plates 9 and It normally do not engage one another. However. the resilient wire mesh II permits the contact I! on plate 8 to be pushed upwardly by the armature 8 into engagement with the contact I3 on plate It, thereby closing the circuit through these contacts and causing current to flow through the lamp amass? electrodes, heating them to electron-emitting tures.

Although the line to which the lamp circuit is connected will normally be a 60 cycle A. C. line, the armature Swill-not be drawn upwardly within the solenoid 120 times due to inertia of the arma ture, the .diilerence in spring tension of the meshes H, and the tendency of the contacts I! to stay closed. The contacts 13 will not Just touch each other and break away quickly. When the armature 8 moves upwardly within the solenoid 6 the upper end thereof will engage the contact it of plate 2 before its upward stroke is completed. As it continues its upward movement it will push the contact ii of plate 9 upwardly. The contact i3 of plate 9 will move upwardly with the application of very little force thereto because the resilient wire mesh II to which it is connected will readily distend. The upward stroke of the armature 8 is not completedwhen the contacts is on plates 9 and I engage one another. As the armature continues its stroke, the resilient wire mesh H to which a contact I! is connected is urged upwardly. Thus the closed contacts 13 move upwardly together and are held in positive engagement until the armature completes its stroke.

when the armature 8 drops down after its stroke has been completed the contacts i3 will tend to stay closed during the time the resilient wire meshes ii on plates 9 and I0 return to their normal positions. While these contacts are closed, pro-heating current will flow in the lamp vtuated. when the defective lamp is replaced the cut-out it may be reset by pushing down on the tab l1.

Theglowlamptisprovidedwithapairofelectrodes and a filling. of an inert gas therein. The glow lamp is designed to pass enough current upon the application of a 110-120 volt line thereto to energize the solenoid 0 and actuate the armature 8 but not enough current to energize the solenoid alter the fluorescent lamp lights.

The several elements of the starter assembly may be connected in accordance with the circuit Yof Figure 2, by metal strapping, and a sleeve of paper tubing may be slipped over the body member I with an end thereof eng in the shoulder 27. The sleeve may be cemented to the body member I. Alternatively the body member I may be provided with grooves through which wires may be run to connect the several starter pa -t with the other contact upon energization of said electrodes. Normally the contacts will be closed long enough to permit the lamp electrodes to be heated to electron-emitting temperatures and when the contacts open the inductive surge from the reactance coil will initiate a discharge across the lamp.

It has been found highly advantageous to have the resilient metal meshes H under difierent tensions because it aids in preventing the starter from operating in synchronism with the 60 cycle current orin such a way that the contacts will always break at other than near peak cycle voltage. The starter operates more satisfactorily when it operates at less than 60 cycles per second because it provides a longer electrode preheating period and enables one to insure the breaking of the contacts at or near peak voltage.

If the lamp fails to start, the armature 6 will continue to operate, causing the above-described cycle of operation to be repeated until the lamp starts. If the lamp fails to light after a reasonable time and after several cycles of operation of the starter, the starter cut-out Ii will be actuated automatically. Actuation of the cut-out i8 disconnects the starter from the circuit thus protecting it from further unnecessary operation.

As mentioned above, the cut-out I8 is made of bi-metal. The tabs I 5 on the plate ll normally engage the cut-out i6 and close the'circuit therethrough. Repeated attempts of the starter to cause the lamp to light will heat the bimetallic cut-out it enough to distort it sufllciently to cause it to snap away from its normal contactwith the tabs IS on the plate l0, thus breaking the circuit therethrough. The tab I! which is mounted in the cut-out i6 and which extends through the aperture [8 in the body member I will be pushed upwardly when the cut-out'is acsolenoid.

2. A magnetic switch comprising: a solenoid; an armature disposed therein; a metal plate secured adjacent the end of said solenoid, said plate having a resilient substantially spiral metal mesh on a face thereof. and an electrical contact centrally mounted on said mesh; a second metal plate disposed above and in register with and insulated from said first metal plate, said second plate having a resilient substantially spiral metal mesh on the face thereof adjacent the first metal plate, an electrical contact centrally mounted on said mesh and in register with the electrical contact on the first mentioned mesh, said armature moving one of said electrical contacts into engagement with the other contact upon energization of said solenoid, and a pair of metal tabs mounted on the periphery of one of said plates and extending inwardly across the top ,face thereof, and a bimetallic plate disposed above and in register with said tab-bearing plate and normally engaged by the tabs thereon to complete a circuit through said contacts and said bimetal plate.

' GEORGE W. PEARCE.

nur'nasncss crrnn The following references are of record in the file 01' this patent:

UNITED STATES PATENTS Cohen Oct. 19, 1948

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