US2343262A - Electric discharge lamp starting device - Google Patents

Description

H. J. M CARTHY ELECTRIC DISCHARGE LAMP STARTING DEVICE March 7,1944.

2 Sheets-Sheet 1 Filed Nov. 1, 1941 A mtl Fig. 4.

Henry JMO (iv-fl INVENTOR. BY 6 ATTORNEY March 7, 1944.

H. J. M CARTHY ELECTRIC DISCHARGE LAMP STARTING DEVICE Filed Nov. 1, 1941 2 Sheets Sheet 2 Fig. 2

Fig 5 AT-ro my oi'therelayoi icui-ei.

Patented Mar. 7,1944

y 2,343,262 ELECTRIC mscmmen LAMP srmrmc I nrzvrca Danvers, Products ire J. McCarthy, s rania Electric Application November 1. 1941, .Serial No.

3 Claims.

This invention relates to electrical circuit reing the electrode pie-heating period or electric gaseous discharge lamps.

An object of this invention is to provide a fluorescent lamp starter switch which will not only operate to provide a pre-determined heating Figure 1 invention;

2 is a schematic dia ram or the circuit Figure 3 is a schematic of another of other-alternate circuit.

In the operation or electric gaseous discharge tain, the relay trode pre-hea ing round the thermal relay shown in my co-pending application Serial Number 335,968, filed May 18,

consists of a therm'alreshown in the co-pending My present invention lay of the general type is a projection of the relay of my lays and more particularly to relays i'or rezulaty of these regard, I have thro NT OFFICE Mass. assignmto Inc., a corporation nine down the relay support I.

ting the conduction of heat from I find it more thermo-plastle anda final coat of thermo-settinz In some cases,

it may be convenient to be advantageous. v A high resistance contact 45, such as nickel, lic strip 12 so tha sistance contact same reason, the low resistance contact I! on from the contact i3 take place at about the breaks away from the or an electric discharge device is accomplished by connecting a resistance rod. a contact oi high contact resistance, and a bimetallic strip with the relay as above-described. The wire 4 which connects the wire rod l with the lead-in wire 1 coming up from the base pin l has the resistance rod l9 mounted thereon. The bimetallic strip 20 is fixed at one end on the wire 4 and runs along the longitudinal axis of the resistance rod l9 and adjacent thereto to a point beyond an end of said rod. The contact of high contact resistance, such as carbon,

2! is attached to this free end oi the bimetal 20 by the supporting clip 22 and when the circuitthrough the relay is unenergized this contact 2i is closed with the wire 4.

In Figure 2, the lead-in wire 29 iromone end of the electrode 23 is connected to one end of the power line from which the apparatus is operated. An end of the other filament 24 is connected through a suitable ballast impedance, such as an inductance coil 32 to the other end of the power line by the lead-in wire 30. The other ends of the electrodes 23 and 24 are connected together by the lines 33 and 31 respectively through the relay,

when the line voltage is'placed across the circuit terminals 29 and 40, the electrodes 23 and 24 of the lamp 26 will immediately start to heat. The heat conducted to the bimetallic strip I! of high contact resistance will heat it suillciently to cause the bimetallic strip to break away from the contact. rate resistance and a low resistance contact may well be used instead of carbon or other ,high, resistance contact, for in either case, heat will 2 which supports the resistance c A sepaend of the bimetallic strip begcnerated to actuate the armature 20'. This timed that it will normally same moment that the electrodes have been sufilciently heated to support the discharge across the lamp. Since there is about one-half line voltage across the resistance rod during the operation of the lamp, the heat,

conducted to the bimetallicstrip by the rod will cause the strip to take a position,,during the actual operation of the lamp, at a point about half way between its normally closed position, with the high resistance contact 13 and the low' resistance contact 18. Thus there is no danger of the strip l2 cooling to a temperature where it would re-establish its contact with the high resistance contact and thus renew the starting operation.

If the current should be thrown oil, and immei diately thrown on again without sufllcient time: elapsing to allow the strip l2 to cool, or if, for any reason, the arc failed to strike when the strip i2 broke away from the high resistance contact l3, the full line voltage would be across the resistance l and the strip l2 would be heated and continue to be deflected further away from breaking away is so the current passing namely, intermittent glowing at the electrodes. To overcome this I have arranged the elements as shown in Figure i so that after the relay has completed several cycles oi operation in attempting to start the lamp, the relay will be cut out from the lamp and will no longer try to start it.

Under ordinary starting conditions, when the lamp starts after the first or second electrode pro-heating interval, the resistance rod I! will not pass much current, it being shorted out and through the high resistance contact 2i and the bimetal 20. However, when the lamp arc fails to strike after several preheating intervals ior the electrodes thereof have been provided therefor by the bimetal i2 and its associated high resistance and low resistance contacts, the high resistance contact 2! and the bimetal 20 will have passed current long enough to cause the bimetal 20 to become distorted sufilciently to cause the contact 2! attached at the free end thereof to break from its normally closed association with the wire 4. When this takes place, the current through the resistance rod I! will be enough to keep the bimetal 20 sufiicientiy distorted to keep the high resistance contact 2! on the free end thereof open with respect to the wire 4.

,cut-out' has come into operation, will, be about the same as'lamp voltage, thus causing the free i2 to assume a position about half way'hetwecn the high resistance contactfl3 andathelow resistance contact it. Thus,

not' only-will the operation of the relay in pro- "viding a succession of filament preheating interbe arrested, but, what is also of' great importance, the. several elements of the relay will not be subjected to excessive voltages due to the abnormal condition of a failed lamp. In this way, the life of the relay is prolonged considerably. The several delicately, adjusted parts are not called upon to withstand an overiailed lamp conditions. Although I have shown a of my invention in Figure 1, it must be understood, however, that some of the elements contained therein may be changed in certain rethrough the resistance ted the high resistance contact l3 until it struck the low resistance contact of the lamp electrodes. If the lamp arc fails to strike when the bimetallic strip i2, now cooling,

low resistancecontact i6,

i6, thus short-circuiting the resistance rod i and starting the pre-heating tact 21 may the free end of bimetal will be obtained for in however, it. should be tension with'which the ,the carbon ooritact 2i or the tension with which spects without departing from the spirit of the invention. For example, the high resistance conbe fixed to the wire 4 instead of to 20 and the same result I either case, the bimetal will become distorted sufficiently under abnormal lamp conditions to cause it to break the circuit 'therethrough and allow the current to flow iii. In either case, made certain that the bimetal i9 is closed to thecarbon contact .l' is closed with the wire 4 is greater than theitension with which the car- 'bon contact l3. lS 1C10S6d with the armature l2.

This is necessary to insure cutout from operating-under the prevention of the I normal lamp and relay operating conditions. Another embodiment of this-cut-out without departing from the spirit of the invention would be the location of the contact of high contact resistance 2| above the resistance rod i9 instead of belov it as shown in Figure 1. In this case the tension between specific embodiment insure relatively quick operation of the cut-out under failed lamp conditions for when the contact is located in this position it doesn't become fheated as quickly as in the position illustrated in Figure 1.

Figure 3 shows another embodiment of my invention different from Figure 2 only in the dottedline-enclosed cut-out unit. This cut-out can be utilized with various forms of starting relays whether they be thermal or glow. A glow relay, for example, is shown in my United States Patent 2,277,708, issued March 31, 1942, on an application filed March 18, 1940. In this figure, the resistance i9 is connected in parallel with the imput terminals 35 and 36 oi the relay 31, and the contact 2| in this case need not necessarily be of high resistance.

again permit said repetitive starting attempts: said second switch including a contact and a thermally responsive switching arm arranged to remain in closed relation with each other with the switching arm unmoved during a plurality of said repetitive starting attempts, and to thereafter separate to break a lead to said repetitive switch and terminate the operation thereof, and a heating element, in operative relation with said switching arm to automatically cause said separation, and in shunt with a series arrangement comprising said thermal arm, said contact,

a and said repetitive switch.

The cut-out assembly may be mounted on the wire 4 or on the corresponding wire 5 or the other side of the relay without departing from the spirit of the invention. The schematic diagram of the relay as shown in Figure 2 illustrates this construction, while the construction of Figure 1 is schematically illustrated in Figure 4.

What I claim is:

i. In combination with an electric discharge lamp and operating circuit therefor, a starting unit including: a switch, for relatively fast repetitive operation in a series of attempts to start said" lamp, comprising heating means and, a thermally responsive switch member in such arrangement that repetitive full energiaations of said heating means consistently and continually cause said switch member to close said switch in like repetition; and a second switch, separate. distinct, and spaced from said repetitive switch,

, for relatively slow operation to automatically terminate said repetitive operation oi said repetitive switch and thereafter, upon deenergization of said circuit, to automatically reset itsel! to.

2. A starting unit for an electric gaseous discharge device, said unit comprising: a plate-like base of insulating material; a panel-like upright of insulating material mounted on said base; 'a pair of contact pins extending from one side oi said base; a pair of lead-in wires, each connected to one of said contact pins and extending from the other side of said base; a switch assembly mounted on said upright in connection with said lead-in wires and including a heater element, a thermally responsive member mounted in heat-receiving relationship with said heating element, and a contact assembly including a supporting arm and a contact member, with said thermal member in normally closed relation with said contact member; and a second switch assembly connected with said first named switch assembly and one of said lead-in wires and including heating means and a hook-like thermally responsive member arranged to short circuit said last named heating means when sufllciently heated thereby.

3. The combination of claim 1, and resistance means in series with, and in proximity to. the thermally responsive switching arm to heat the same on passage of current therethrough.

J. MCCARTHY.

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