US2479372A - Starter on low-pressure fluorescent tubular lamps - Google Patents

Description

Aug. 16, 1949. KNQBEL 2,479,372

STARTER ON LOW-PRESSURE FLUORESCENT TUBULAR LAMPS Filed Feb. 21, 1947 2 Sheets-Sheet 1 FIG.

m Emma:

F. KNOBEL 2,479,372

STARTER ON LOW-PRESSURE FLUORESCENT TUBULAR LAMPS Aug. 16, 1949.

2 Sheets-Sheet 2 Filed Feb. 21; 1947 Patented Aug. 16, 1949 UNITED STARTER ON LOW-PRESSURE FLUORES- CENT TUBULAR LAMPS Fritz Knobel, Ennenda, Switzerland Application February 21, 1947, Serial No. 729,960 In Switzerland March 2, 1946 2 Claims. (01. 315-100) My present invention relates to improvements in starters for low-pressure tubular lamps with series reactors or chokes, comprising a breakcontactor connected in series with the choke and biased by a hot wire so as to break upon passage of current and to cause, in combination with a condenser connected between the two electrodes, an automatic arcing of the fluorescent tube. The objects of my improvements are first to dispense with the resistor used in prior art for actuating the starting contactor, which resistor reduces the starting potential and thus impairs the starting operation, second to reduce the mass of the heating wire so as to render the starter readily responsive with a view of speeding up the starting,

operation, and third to substantially simplify the tube construction and the operative wiring by eliminating the heating of the electrodes and by using only a two-wire tube connection.

I attain these and related objects by the starter and the Wiring schemes, shown by way of example, in the accompanying drawing, in which Fig. 1 is an elevation of the starter, with cover removed,

Fig. 2 a top plan view of Fig. 1,

Fig. 3 a wiring scheme of a starter on a fluorescent tube with heated electrodes, and

Fig. 4 a wiring scheme of a starter on a fluorescent tube with cold electrodes,

Fig. 5 a modified wiring scheme of a starter on a fluorescent tube with heated electrodes,

Fig. 6 an elevation of a starter modified relative to that shown in Fig. 1, and

Figs. 7 and 8 are cross-sections on lines VII- VII and VIII-VIII respectively of Fig. 6.

The starter according to Figs. 1 and 2 comprises a housing I of insulating material, in which all the parts are mounted. The two parts 2, 3 of the break-contactor shown are riveted, together with the appurtenant connecting lugs 4, 5 into housing i. so that part 2 is electrically connected with lug 4, and part 3 with lug 5. Further, two studs 6, l are riveted to junction lugs 8, 9 to form an electrical connection. A bush [0 is pivoted on stud I, and connected to an actuating arm I I. One end of a heating wire I2 is wound on bush Ill, and the other end secured to stud 6. Heating wire I2 is kept stretched by a tension spring l3 engaging arm H, and an insulating cap 14 carried on actuating arm II is situated in its position of rest at a certain distance from the movable contact portion 3 of the break contactor.

In the wiring diagram according to Fig. 3, one of the two terminals l5, l6, namely terminal 15,

Jr: is connected with junction lug 8 of heating wire l2, while a circuit is completed from the other junction lug 9 of heating wire l2 over thermofuse ll, reactor coil 18, terminal l3, heating electrode 20 of the fluorescent tube 2i, terminal 22, junction lug 5, break- contactor 3, 2, junction lug 4, terminal 23, the other heating electrode 24 01' tube 2|, terminal 25, and the second reactor coil 26 to the other terminal IS, a starting condenser 21 being interposed between the terminals l9 and 25, which at the same time serves for radio dehumming.

When engaging the starter, the electrodes 20, 24, are heated at once, and heating wire I2 is expanded, thus turning actuating arm H in direction of the arrow shown in Fig. 1. Actuating arm H, after covering a certain non-operative path, breaks contactor 2, 3 by virtue of insulating cap 14 biasing contactor portion 3, thus breaking the circuit, and heating wire l2 rapidly cools off again. The break-contactor is again closed, and such alternation is continued, until the fluorescent tube has been started. Current, now, flows continuously from network terminal I5 over lug 8, heating Wire [2, lug 9, thermo-fuse ll, coil l8, terminal l9, electrode 2|], through tube 2|, electrode 24, terminal 25 and coil 26 to network terminal l6. Thus a current flows continuously through the heating wire l2, and break contactor 2, 3 is held broken.

The starter described, in contra-distinction to starters of prior art comprising glow relays or bi-metal contactors, possesses the advantage that no resistor connected parallel to the fluorescent tube is provided for actuating the starting con-' tactor, which resistor reduces the starting potential and thus impairs starting. Further, the mass of the heating wire used is so small that the starter responds very quickly, and starting therefore, takes place rapidly.

In the wiring diagram according to Fig. 4, a fluorescent tube 28 with cold electrodes 29, 30 is used, which is connected to the terminals 3|, 32. Further, a choke or reactor coil 33 is provided for. When switching on this starter, a ircuit is completed from network terminal l5 over hot wire I 2, thermo-fuse ll, choke coil 33, and break-contactor 3, '2 to network terminal I-B. Contactor 3, 2 thus is alternatingly made and broken, as in the first example, until an arc strikes along tube 28 by the action of the starting condenser 21 upon which a continuous flow of current takes place from network terminal l5 over hot wire [2, thermo-fuse ll, choke coil 33, terminal 32, electrode 30, tube 28, electrode 29, and terminal 3| to network terminal l6; and break- contactor 2, 3 is held broken.

The example according to Fig. 4, as will be ape preciated, substantially simplifies the tube construction and the wiring scheme, in that heating the electrodes may be dispensed with and only a two-wire connectipn. is required for the tube.

The example according to Fig. 5 difiers from that shown in Fig. 3 in that only one reactor 34 is provided for, and that heating wire I2 is con this is a point of particular interestoncand the Heating wire I2 thus may be made sufiis.

same starter may be used for all types of tubes .or instruments having different current ratings, an adaption only being necessary insofar as the number of turns between the end of reactor 34 and the -tapping for the heating wire is chosen such'that the-voltage'arising on the heating wire at-ratd current correspond to the requirements Iorea'chtype-of instrument.

' Thefstarter accordingto Figs.- 6-8 differs from thatshown in Fig, '1 in that the two studs 6, 1 supporting heating wire-l2 are-mounted by means of a metaltransverserail 35. Stud 6 is riveted we rail ffiinnlx'whereas lug- 8 is secured to housing l 'by-a-rivet 35; An extension 31 of heating wire-121s passed through housing I and soldered to ,lug 8. Stud 1, however, at the same time serves ionconnectingrail 35' tohousing I, passing throughtheilatterand being-riveted to lug 9. An insulating-ring .38 is disposed between stud 7 and rail '35; By such-arrangement of a metal transverse rail,- fh'eating wire: l2 becomes 7 independent bran-expansion of' housing I which expansion maybe considerable for a Bakelite housing for eiia-mple' d Whatfclaim and-desire tosecure by Letters Patentis: V I

'1: w A low-pressure fluorescent tube starter comprising an insulating housing, a break-contactor mountedin-the-latter, two studs, a metallic rail secured inthesaid-housing by one of the said 7 '4 studs for independent expansion, a pair of lugs for electrical connection mounted outside the said housing and secured to said studs respectively, a washer insulating one of the said studs from said rail, a bush rotatable on one of the said studs, a heat-responsive wire disposed between the saidstuds and having one end secured to said bush, a spring-loaded arm Secured to said bush, and an insulating cap mounted on the free end of said arm; the whole in such combination that the said contactor is broken through the swinging action-of thesaid arm after the said Wire has been heated, so that the current will pass through the fluorescent-tube.

2. A starting device for a low-pressure fluorescent tube including-a pair of tube electrodes, comprising-in combination an insulating hous ing,.-.ajbreak-oontactor mounted in the latter and connected in series with said electrodes, two studs, a metallic rail secured in the said housing by one of the said studs for independent expansion; a pair of-lugs for electrical connection mounted outside; the said housing and secured 'to-said' studs respectively, a washer il'lS'll? lating onepf the said studs from said rail, a bush rotatable-on one of-the said studs, a heat-responslve wire disposed between the said. studs and havingeone endsecured to said bush, a springloaded arm securedto said bush, an insulating cap mounted on-the :freeend of said arm, a single, choke in circuit for said electrodes and means for connecting one terminal of said heat responsive Wire to difierent intermediate points on said choke for the purpose ofadapting one and the wint r Starter to tubes ofdiiierent current ratings.

' FRITZ KNOBEL. I

REFERENCES? CITED The -f o ow .n r referen es. are of re rd in the file of this. patent:

g STATES- PATENTS Number Yost sin in -U.- .sv-e- 0 1942

Images