US2379300A - Fluorescent lamp starter - Google Patents

Description

June- 26, 1945. c. H. HODGKENS FIsUOESCENT LAMP STARTER 2 Sheets-Sheet 1 Filed Feb. {1, 1942 INVENTOR '6'. HODGK/AS. BY 10%,, l .k 5

' ATTORNEY June 26, 1945. c. H. HODGKINS FLUORESCENT LAMP STARTER Filed Feb. 4, 1942 2 Sheets-Sheet 2 INVENTOR c'. H. HODGIfi/VS ATTORNEY tion.

" Patented June 26,

, Charles n Hodgkins, Fail-seal, cums,

Company, Conn., a corporation of Connecticut Application February 4, 1942, Serial No. 429,461

The Bryant Electric assignor to I Bridgeport,

, 11 Claims. (Cl. 2oo-122 I The present invention relates to thermal relays;

and more particularly to such relays for thestarting of electric dischargelamps of the fluorescent ype Lamps of the fluorescent type are now wellknown to the art and in order to operate such lamps from the customary domestic source of potential of about 115 volts, they are provided with filamentary electrodes which must first be heated to an electron-emitting temperature prior to application of a sufiiciently high starting voltage across the preheated electrodes.

To obtain this sequential operation, a relay is customarily employed which first connects the filamentary electrodes of the lamp in a series heating circuit to the source, and after the electrodeshave been heated to-electron-emitting temvention to provide a relay which may be em-v perature, the relay opens this series heating cir-,

cuit causing a high voltage surge from an inductance element necessarily disposed between the I source and one'of the electrodes of the lamp.

This high voltage. surge is usually sufliciently above line H voltage to cause a discharge between the preheatedlamp electrodes, and once started, the operating voltage of the lamp is below line voltage so that the discharge is readily sustained at the availabl'domestic potential of 115 volts. r

If for any reason the discharge isj not initiated on the first operation of the relay, it continues to perform its cycle of operation until the discharge is actually struck-between the electrodes and the lamp finally started. Thus there are several primary requisites for a starting relay for this purpose. .It must first maintain the series heating circuit closed for a period of time sumcient ,to bring the-filamentary lamp electrodes up. to full electronsemittingtemperature prior to interrupting this circuit with causation of the high voltage surge from the inductance element,'otherwise. the

filamentary .electrods will be stripped of their electron-emitting coating 'by the high voltage surge. Secondly, the relay must, as above noted, continue its cyclic operation provided the lamp start the lamp I to prevent the consumer from waiting in thedark for the lamp to give illumina- Relays of this type have heretofore had disadvantages resulting from their above noted requisites. One such disadvantage has been that a relay of diife'rent electrical characteristics has been required for practically each wattage fluorescent lamp because of the diiference in size 01; of Fig. =1, showing position at the instant of failsto start the first time, and its entire cycle of operation must occur as quickly as possible to rangement' for starting and operating'a fluoresso centlamp and showing-the; normal position of' the filamentary electrodes for the various wattage lamps and the voltage that must therefore be applied. In addition, the primary requisite for repetitious operation of the starting relay is itself a distinct'disa'dvantage under certain conditions.

For example, in the case of a failed fluorescent lamp the relay has heretofore continued its cycle of operation in a vain attempt to start the lamp in the same manner as though the lamp had merely failed. to start on the first few operations of the relay. This not onlygreatly affects the useful life of the relay itself, but causes flickering of. the failed lamp, which is a source of considerable a-nnoyanceto the user.

It is accordingly an object of thepresent in ployed for starting fluorescent lamps regardless of their particular wattage.

Another object of the present invention is the provision of a relay for the starting of fluorescent discharge lamps which automatically operates to effectively disconnect the lamp from the source whenever the lamp fails for any reason.

- Another object of the present invention is the provision of a relay for starting fluorescent dis-1 will become obvious reference to the accompanying. drawings wherein:

Fig.1 is a front elevationalview of the prebut taken at to the latter;

I 1m 3 is a fragmentary sectional view taken in I theIineIH- -IIIo fF IgLI;

charge lamps which may be universally employed for starting such lamps regardless of their par- 7 ticular wattage and wherein the 'relay is .au'wmatically operable "to disconnect thelamp from the source of supply in the event the lamp has I failed. I w I Another'object ofthe present invention is the provision of a thermal relay for starting fluorescent discharge lamps which performs its sequentialoperation with fidelity and ical to manufacture;

still further objects of the present invention to thosefskilled in the art" by ferred form of starting relay for fluorescent lamps and showing the container therefor in section;

Fig. 2 is a fragmentary view similar to Fig. 4 is a schematic diagram of a circuit at}- the relay of the present invention before, or a second or so after, closure of the lamp energizing whichis econ'omrelay when employed with lamps of a wattage in excess of 30 watts;

Fig. 8 is a sectional view VIII-VIII of Fig. 1:

F1893 is an elevational .view

r the bimetallic element of the relay of Pig. 1;

( Fig. 10 is an elevational view of a modification which the starting relay of the present invention may take;

Fig. 1'1 is a side elevatlonal view of the modification shown in Fig. 10, and v v,

Fig. 12 isa sectional view taken on. the line xix-4m of mg. 10. ,i o

Referring now to the drawings in detail. the starting relay "of the present invention is shown takenon the line generallyatIintheseveralilguresandisho sc fv within a metallic or plastic casing I together with a radio frequency condenser I, both of which are connected in electrical parallel to a pair of contact terminals U and I adapted to engage a socket,

andsecuredtoaninsulatingclosuremember ll.-

The relay 117881! a base HOf suitable insulating material such as fiber, a phenolic condensation product, hard rubber, or the'iike,

and isv provided with a rectangular open '3 therein. A substantially U-shaped heat-responsive element II in the form of a bimetallic memher, having one leg thereof longer than the other,

issecuredalongthelongestl'egtoaneyelet or the like ll, which forms a pivoted support and,

fllamentron-emitting temperature prior to the initiation of a discharge between these electrodes. To this end one side of the electrode fl is mnnected by a conductor ll, inductance l2, and switch 88, to

one side of the domestic source of supply of .ap-

proximately 115 volts, and one side of the electrode 28 is likewise connected by a conductor 34 to the other side of this source. In order to complate a series heating circuit for these electrodes 28 and 2|, the remaining ends of eacheare connected together by the relay I which is secured to a suitable socket (not shown) so that the terminals I and 8 together with conductors II and Il complete the circuit.

Upon closure of the switch 33 a series heating circuit will be thus completed through inductance II, electrode ll, relay 5, and electrode it back to the source LI-LI, which may be a transformer or a domestic source of ll5-volts, as is well-known. in the art. Since this circuit arrangement per se is well-known, it is believed unnecessary to trace the circuit in its entirety, and consequently further description will be confined to the relay "8. The current passing through the relay 5 with the switch 83 closed wlil iiow from the contact terminal I and strap II to .the eyelet 20. Since one end of the resistance heater II is connected to this eyelet 20 by the conductor 12, current flows through this heater to heat collector it, .through normally closed contact II, the upper portion of the longest leg of heat-responsive element 13, and t ence through supporting eyelet I l and strap I to contact terminal I, thus subjecting the heater I! to full line voltage. 7 I

Inasmuch as the heater II is disposed longitudinally of the longest leg of the heat-responsive element It between its pivot I4 and the base of the U, thehea't generated by the application of the voltage from the source, which will be across electrical connection for the heat-responsive ele-.-

ment II, with this eyelet'il being connected to theoontactterminall byametallicstrap II and to one sideof the condenser 1 by a conductor It.

The free'end with a suitable contact I! normally engaging a metallic heat collector It in the form of a supporting strap having its mgularly disposed end i (Fig. 2) rigidly'secured to the base" H. A high ohmic resistance heating element I! is electrically and mechanically secured to the heat collector II and disposed longitudinally in juxtaposition' to the longest leg of the heat responslvc element II between its support It and the bottom of the U, with its other end electrically connected to an eyelet II by means of a conductor 22. This eyelet fl, like the eyelet ll, passes through'the base of therelay and is connected by a strap :orthelikelltothemmttemhialllhdw v of the longest leg of the U- shaped heat-responsive element II is provided iieetion of that portion, together with thebottomtheheater, hereinafter referred to as full line voltage, is rapidly transferred to the adjacent portion of the heat-responsive element ll. De-

of the U, occurs, in the direction of the base H with the bottom of the U passing inwardly of the rectangular slot I! provided forthat purpose. Deflection in the direction of the base Ii will socordingly cause the shortest leg of the heat-retheremainingsideoftheconden-serlhyccon-- (motor as (no. a contact as is electrically .andmechanicallysecuredbytheeyeletllsoas to benormally i w edinspacedrelationtoa contact Ilrigidlysecured totheshortest leg of the heat-responsive element It so that these two contacts will engage each other as hereinafter Referring now'more particularly to Fig.1, the

operationoftherelaylwillbedeseribedincon neetlon with itsintended purpose of starting a fluorescent lamp l'l. the'lampll is th filamentary electrodcsfiandllwhiehnmstbeheatedtoelecvAsrshown-in this fi ure;

Bio:- anyreasonthe dischargoisnotinitiated' sponsive element to move away from the base until contact II engages contact 2!, in the mannot shown in Fig. 5.

This enga ement of the contacts 2 and II occurs very rapidly, requiring only a very few seconds,. with the result that a low resistance heating circuit is provided for the lamp electrodes fl and 20, allowing them to be heated quickly to maximum electron-emitting temperature, since .the heater II is short-circuited by the engaget-circuitment of the contacts II and I. Shot ing of the resistance heater It results in no further generation of heat so that the heat-responsive element ll cools suillciently to'cause it to return to its normal position with attendant separation of the contacts It and 2|. Separation of the latter accordingly causes a high 'voltsge surge from the inductance element 82 which is impressed across thepreheamd lamp electrode Ilyand ",thus striking the are with then being in theposition as shown in I'll.

1m the'flrst operation offthe relay. I, thegheatsr Is is liainimmediately hibiscus tofullline voltage, withthe result that it will repeat it cycleof operation a number of times until the discharge is initiated.

Once the lamp -2'I is started, the heater. I9 is then subjected only to -lamp voltage, and on lower wattage lamps the size of the heater "and area or the heat-responsive element ll are so designed that insui'iieient heat is generated at lamp voltage to materially aflect the heat-responsive element [3 or to cause closure of the contacts is and a during operation of the lamp. 10

For higher wattage lamps which necessarily require a higher lamp voltage, suflioient heat-would unavoidably be generated to cause closure of thecontacts 34 and It in the absence of provision ,to the contrary. Accordingly; in order to universally adapt the present relay .to all commercial wrtisage lamps, the. heat collector ll and contact I are provided. I

In the case of higher wattage lamps where the heater is subiect to a voltage approximating line voltage during operation oi the lamp, the heat generated bythe heater I! will be carried to the heat collector II; and since the latter is disposed adjacent the upper portion of the-longest, leg oi the U-shaped'heat-responsive element It which is'in the electrical'ci'rcult, this portion will be and into the rectangular opening 42. Again, this deflected by the heat toward the base u, thus opening the contacts I! and I8 before the contacts 2 5 and It can close, as shown by the" position of the relay in Fig. 'l. Inasmuch as this com pletely disconnects the heater I9 from the source,

there will be a continual opening and closing of the contacts I1 and I! as the heat-responsive eiducting material, such as silver or copper, and is of such-shape and proportion that 'it';will permit a number 01 operations of. the relay 5 before thermally "locking" the relay in an open circuit condition, as well as permitting closure of the contacts 25 and 26, in the case of higher wattage lamps before causing continual opening and closing of the contacts l1 and 18. Moreover, the

thermal mass of the heat collector l8 should -be' heat will again be transmitted to'the U-shaped I heat-responsive element 43 with attendant deflection of the leg adjacent the heater, and the bottom of the U in the direction of tire base 4| will cause movement of the other leg or'the U away from the base 41 until the contact 46 carried by the free end thereof engages the stationary contact 45 carried by the eyelet 40, as previously described relativeto the preferred modification of Fig. 1. The heater 49 isv thus shortement responds toheating and cooling, due to intermittent current flow through the heaterjll.

However,- in the case of allwattage lamps, should it fail to start on the first separation of contacts 25 and, the heater II will again be, subject tofull line voltage with repetitious operation of the relay as above noted. I

-Inaddition to the relay 0! the present invention being universally adapted for all commercial wattage-lamps, it i also operative to "lock-out the discharge lamp should it fail, due to deactivation of the electrodes oBsimilar cause. In an instance of this kind the relay 9 will periormitsl cycle of operation a number oi times corresponding to a predetermined period or time, as before -mentloned, and during each attempt to start the lamp 21, the resistanceheater is will be subjected to full line (as distinguished from a high lamp voltage as'in of high wattage lamps) with the heat generatedthereby being accumulative. The temperature of heat collector l! accordingly will finally reach a value that will;

and making of the heat; ing circuit by opening and closing or the contacts cause a cyclic breaking Fl and I9. Durin time is insuiiicient to permitheating of the lower portion of the U-slvaped bimetallic-element I! to Consequently. attempted starts of the lamp will be eliminated since it will be "locked-out" due to the inability oi the contacts 2| and 16 to close again, with the relay I remaining in the position the cyclic operation, the closedclrcuit '{shown in Fig. 7. The current flowing through the ballast or inductance 32 will be reduced to the circuited and upon cooling of the heat-responsive element 43, the contacts 45 and-46 separate to causethe high voltage surge with initiation of the discharge between the lamp electrodes.

After. starting of the lamp, the heater 49 will again be subjected only 'to lamp voltage at which insufficient heat. is generated by heater 49 to cause closure of 'contac 45 and. Should the lamp fail to start on thegflrst operation of the relay 5, it willcontinue its cyclic operation several times until the discharge is finally initiated in the H lamp. In the event, however, that the lamp has failed due to deactivation of the electrodes'or similar cause, the heater 49 will be subjected to full line voltage each time the contact separate. As in the previous embodiment, a heat c0lleo-' 0- tor 49 is provided whichin the modification of Figs. 10, 11, and 12 partially surrounds'and intimately contacts the heater 49 and is so shaped and arranged tratanother portion I0 is disposed in juxtaposition tothe' leg of the U carrying the contact-48. The heat generated by repeatedly subjecting theheater 49 to full line voltage is again accumulatively transmitted to the heat I collector 48 which accordingly flows to the portion 99, causing the leg of the u-shaped bimetallic element carrying the contact 46't0 be heated and to deflect toward the base 4|, thus preventing e closure of the contacts 49 and 46 and "lockingt e point where. contacts I! and 29 will close.

value which flows through the heater l9 dur--' ing the closedv portion or the cycling of the heater circuit, thus preventing detrimental effect to the inductance, as well as to the relay I itseli by *overheatingjor a prolonged; period or time.

'To accomplish the operation as above noted, the heat collector II must be'oi' good heat conout the defective lamp, thereby eliminating attempted starts with annoying lamp flicker. The

current in the ballast 32 is also again reduced to that value which flows "through high ohmic rer-istanoe heater 49. thus protecting the ballast agrinst detrimental or destructive current. Upon replacement of the failed lamp, the relay 5 again returns to its normal position ready for its cyclic operation.

It thus becomes obviou lamps of the fluorescent type is herein provided which is simple and economical to manufacture.

,Moreover, such relayis universally operable to to those skilled m' the art that a thermal relay for starting discharge start fluorescent lam s or all commercial watt ages and in addition "looks out a railed lamp so as to eliminate annoying flicker oi the lamp,

and needless repetitious operation of the relay.-."

Upon replacement oi the failed lamp, however, I the relay automatically returns to its normal position and operation. r 7

Although severallembodiments oi the present invention have been shown and'descrlbed, it is to-be understood that still iurther modifications may be made without departing from the spirit and scope of the appended claims. 1

I claim:

l. A thermal relay ior controlling an electric circuit comprising a base, heat-responsive means carried by said base, an electric heater disposed in nest transfer relation tosaid heat-responsive means, means operable in response to heating of said heat-responsive meansby said heater upon the application or approximatelyline voltag to the latter to close the circuit and short-circuit i said heater, and means in heat transfer relation with said heater and said heat-responsive means for accumulating heat therein upon the application approximately line voltage to said heater for a predetermined time and operable to prevent said heat-responsive means from causing circuit closing operation oi said flat-mentioned means and to cause said heat-responsive means toretain said flrst-mentioned means in arropen cirso proximately line voltage to the latter to close the circuit and short-circuit said'heater, circuit-opening means associated with said heat-responsive means and normally included in the circuit, and means in 'heat transfer relation with saldheater .and said heat-responsive means !or accumulating heat therein upon the application oi approximatelygline voltage to said heater ror a prede- \termined time and operable to cause said heatresponsive means to operate said circuit-opening means with attendant interruption oiithe circuit thus preventing said heat-responsive means from 5 operating said circuit'closing means with shortcircuiting of said heater. v

3. A thermal relay for starting fluorescent a lamps of various wattages from secures of electricalenergy comprising a base, a heat-responsive element secured to said base, an electric heater disposed adjacent said heat-responsive element for transmitting heat to the latter upon the flow of current through said heatencircuit-cloaing of said heat-responsive element by said heater upon the application or full line voltage to said lamp and to said heater, to close the circuit to said .lamp and short-circuit said heater and operable toopen upon starting of said lamp and- 65 cooling ofsaid heat-responsive element; and circult-opening means associated with said heat-responsive element 'and normally included inthe circuit with said lamp and said heater, and operable to cyclically open andclose said circuit upon '70 continued heatins or said heat-responsive element,

by the application oi lamp voltage to said heater 1 when such voltage approximates line voltage with higher wattage lamps, to said circuit and prevent said heat-responsive element from- 7 10 means until said lamp is means in heat transfer relation with said heater operating said circuit-closing means and shortcircuiting said heater.

.4. A thermal relay ior starting fluorescent lamps of various wattages from a source or electrical energy comprising a base, a heat-responsive element secured to said base, an electric heater disposed adiacent said heat-responsive element for transmitting heat to the latter upon the flow or current through said heater, circuit-closing normally operable in responseto healing or said heat-responsive element by said heater upon the application or full line voltage to said lamp and to said heater, to close the circuit to said lamp and short-circuit said heater and operis able to open upon starting or said lamp and cooling oi said heat-responsive element: circuitopening means associated with said heat-responsive element and normally included in the circuit with said heater, and means in heat transier relation with said heater and said heat-responsive element ioraccumulating heat therein upon con-- application of lamp voltage to said heater when such voltage approximates line voltage with higher. wattage lamps and operable to cause said said heat-responsive element to operate said circuit-opening means with attendant interruption of the circuit to prevent said heat-responsive element irom operating said circuit-closing means with shortrcircuiting of said heater.

5. A thermal relay for starting a fluorescent lamp from a source of commercial voltage comprising a base, a heat responsive element secured to said base, an electric heater disposed adjacent said heat-responsive element for generating sum-- as cient heat only upon the application or full line voltage thereto to cause deflection oi said heatresponsive element and incapable of -generating suflicient heat to materially afl'ect said heat-responsive element at a voltage below approximately full line voltage, a pair oi normally open contacts operable, to engage each other and short-circuit said heater upon the initial heating or said heat-responsive element by said heater in response to the application of full line voltage thereto, and heat-collecting means in heat transfer relation with said heater for accumulating heat therein upon repeated line voltage to said heater for a predetermined period or time and operable to render said heatresponsivs element inoperative to close and opersaid lamp for generating suflicient heat only upon means normally operable in response to heating 00 element, a pair 01' normally open contacts cyclically operable to engage each other and short-circuit said heater upon the initial heating oi said heat-' responsive element by said heater in response to the application of full line voltage thereto and to open upon cooling 0! said heat-responsive element started, -arid heats-collecting for accumulating heat therein uponrepeated application oi full line voltage to said heater ior a predetermined period or time and operable to to close and operable to maintain said contacts in an open Position application or full 3 asrasoo '1. A thermal relay for starting a fluorescent lamp from a'source of commercial voltage comprising a base, a heat-responsive element secured to said base, an electric heater disposed adjacent said heat-responsive element for generating sufllcient heat upon the application or full line voltage thereto to cause deflection of aid heat-responsive element, a pair of normally open contacts operable to engage each other and short-circuit said heater upon the application of normal line voltage to said heater and initial heating of said heat-responsive element, a pair of closed contacts for normally connecting said heater to said source, and means operable upon the application of line voltage to said heater beyond a predetermined period of time to cause said pair or closed contacts to open and disconnect said heater from said source to prevent said heater from operating said heat-responsive element with attendant closure of said normally open contacts. I

8. A thermal relay for starting a fluorescent lamp from a source of commercial voltage com- Drl lng a base, a heat-responsive element secured to said base, an electric heater disposed adjacent said heat-responsive element for generating sutflcient heat only upon the application of approximately full line voltage thereto to cause deflection of said heat-responsive element, a pair of normally open contacts operable to engage each other and short-circuit said heater upon the initiai heating of said heat-responsive element by said heater in response to the application approximately lull line voltage thereto, a pair of closed contacts -lor ndrmally connecting said heater to said source, and heat-collecting'means operable upon continued application of approximately line voltage to said heater beyond a predetermined period of time to heat said heat-responsive element and cause said normally closed contacts to open and disconnect said heater from said source to prevent said heater irom operating said heat-responsive element with attendant closure of said normally open contacts.

9. A thermal relay for starting a fluorescent lamp comprising a base, a bimetallic element carried by said base, an electric heater disposed in juxtaposition to a portion or said bimetallic ele- .ment and operable upon the initial application of approximately full line voltage thereto to cause deflection oi the adjacent portion of said bimetallic element in one direction, and the remaining portion thereof in another direction, a contact carried by one end of said bimetallic element and engageable by said base for closing a circuit to said lamp and for short-circuiting said heater, and a heat collector in heat transfer relation with said heater and the portion or said bimetallic element remote from saidlieater for accumulating heat therein upon continued application of approximately full line voltage to said heater and operable to cause deflection of the portion of said bimetallic element remote from said heater in the same direction as the portion adjacent thereto to prevent engagement oi said contacts with attendant closure of said circuit and shortcirculting or said heater.

10. A thermal relay for starting a fluorescent lamp comprising a base, a U-shaped bimetallic element carried bysaidbase, an electric heater disposed in juxtaposition to one leg of said U- 5 shaped bimetallic element and operable upon the initial application of approximately full line voltage thereto to cause deflection of the adjacent portion of said bimetallic element in the direction of said base with attendant deflection of the leg thereof remote from said heater away from said base, a contact carriediby the endof the leg of said U-shaped bimetallic element remote from said heater and engageable with a stationary contact terminal carried by said base for closing [5 a circuit to said lamp and for short-circuiting said heater, and a heat collector in heat transfer relation with said heater and the leg of said U-shaped bimetallic element remote from said heater and accumulating heat therein upon continued application of iull line voltage to said heater and operable to cause deflection or the leg of said U-shaped bimetallic element remote from said heater in the same direction as the portion adjacent thereto to prevent engagement of said contacts with attendant closure of said circuit and 'sho'rt-circuiting of said heater.

11. A thermal relay for startinga fluorescent lamp comprising a base, a U-shaped bimetallic element carried by said base, an electric heater disposed in juxtaposition to one leg of said U- shaped bimetallic element and operable upon the application or approximately full line voltage thereto to cause deflection or the portion of said bimetallic element in the directionof said base with attendant deflection or the leg thereof remote from said heater .away from said base, a spaced contact carried by the .end of the leg of said U'-shaped bimetallic element remote from said heater and engageable with a stationary 4 contact terminal carried by said base upon deflection of the leg or said U-shaped bimetallic element for closing a circuit to "said lamp and for short-circuiting said heater, a contact carried by the end of the leg of said U-shaped bimetallic "element adjacent said heater and normally engaging a stationary contact carried .by said base,

7 and a heat collector in heat transfer relation with said heater andthe portion of said U-shaped bimetallic element carrying the normally closed a contact for accumulating heat therein upon continued application of approximately full line voltage to said heater and operable to cause deflection of that portion of said U-shaped bimetallic element adjacent said heat collector to cause disengagement of the normally closed contact carried thereby from the stationary contact carried by said base to interrupt the circuit to said heater to prevent the latter from heating said.

U-shaped bimetallic element to a temperature suflicient to cause engagement of the spaced contact carried by the leg thereof remote from said heater with the adjacent stationary contact carried by said base with attendant closure-of said 6? circuit and short-circuiting of said heater.

CHARLES H. HODGKINS.

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