US2212427A

US2212427A - Electric discharge lamp circuit

Info

Publication number: US2212427A
Application number: US302379A
Authority: US
Inventors: Leo R Peters
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1939-11-01
Filing date: 1939-11-01
Publication date: 1940-08-20
Anticipated expiration: 1957-08-20

Description

Aug. 20, 1940. 1.. R. PETERS 2,212,427

ELECTRIC DISCHARGE LAMP CIRCUIT- Filed NOV. 1, 1939 Figl.

L6 20 a /7 fl! 1 I y l5 /4 I j /o "g;

Fig.7..

Inventor Leo F2. Peters,

H is Atborneg.

Patented Aug. 20, 1940 PATENT OFFICE".

2,212,427 ELEGTRIO DISCHARGE LAltIP CIRCUIT Leo R. Peters, East Cleveland, Ohio, assignor to General Electric Company, a corporation of New York Application November 1,1939, Serial No. 302,379

3 Claims.

My invention relates to gaseous electric discharge lamp devices generally, and more particularly to the starting and operation of such devices employing thermionic cathodes.

It is the practice to start lamps of the type referred to above by connecting them in series with an inductance or choke coil across the terminals of a suitable source of current, and to employ an automatically operable switch or relay 10 to short-circuit the discharge path of the lamp and connect its electrodes in series to heat them, the said switch being then opened to cause an inductive surge in the circuit to start the discharge between the electrodes. In one such circuit, similar to that shown in Patent 1,951,112, G. Wels, assigned to "the assignee-of the present invention, the switch is of a thermal (bimetallic) type, its contacts being normally closed and being opened to start the lamp by a heater element 20 connected in the lamp circuit. In another such circuit, the switch is of a magnetic vibrator type wherein the contacts are also normally closedand are opened by the vibrator coil or magnet which is connected in the lamp circuit. 'In both 25 of these circuits, the actuating element (heater or magnetic coil) of the switch is continuously in the lamp circuit during operation of the lamp to maintain the contacts in open position.

One of the objects of my invention is to pro- 30 vide in circuits of the type referredto above an improvement wherein the starting switch or relay is eliminated from the circuit upon starting of the lamp. Thus, the said switch or relay consumes no wasteful energy during operation of the 35 lamp. Moreover, in the case of the thermal relay,

since the bimetallic element is not heated during lamp operation, it is in proper position for im mediate restarting of the lamp, whereas in a circuit of the type disclosed in the above-mentioned 4o Wels patent, a short interval 02 time is required for the bimetallic element to cool before the lamp can be restarted. Further objects and advantages of my invention will appear from the following description of species thereof.

45 In the drawing, Fig. 1 is a diagrammatic representation of a circuit comprisingmy invention and employing a thermal switch or relay, and Fig. 2 is a similar representation of a circuit employing a magneticvibrator type of relay.

50 Referring to Fig. 1 of the drawing, I II represents a lamp which may be, for example, a low-pressure positive-column gaseous discharge device/ containing a filling of rare gas and/or metal vapor. Thermionic electrodes or cathodes I I-I I are cated at the ends of the lamp container, and are here indicated as coils of refractory metal wire, such as tungsten, coated with suitable electronemissive material, such as alkaline earth oxides. In place of the directly heated electrodes shown, indirectly heated electrodes may, of course, be 5 employed, such as those wherein the coils I I-'-I I serve as heaters for surrounding metal tubes coated with the electron-emissive material. The lamp I0 is connected across the terminals I2I2' of a suitable current source, such as a 115 Volt 10 or 220 volt, 60-cycle alternating current source, in series with an inductance or choke coil I3.

In accordance with my invention, a negative glow lamp I4 is connected in series with the actuating means. or heater coil I5 of a thermal bi- 1 metallic switch or relay I6 across the lamp ID in series with the electrodes Il-I I. The normally open contacts I 'II8 of switch I6 are connected, through the bimetallic element I9 and conductor 20, across the glow'lamp l4 and heater I5. The glow lamp I4 may be a simple neon lamp of a type used for indicator purposes.

When the, circuitis closed, current flows from terminal I2 through the choke I3, electrode ll, switch heater I5,glow lamp I4, and electrode II to terminal l2. The resistance heater l5 heats up the bimetallic strip I9 and causes contacts I'I-I8 to close and thereby short-circuit the resistance I 5 and glow lamp I4, permitting suflicient current to pass through the electrodes IIII' to heat them up. The shunted heater I5 then cools down and the contacts II--I8 open, causing a surge in the circuit which starts the discharge between the electrodes IIII. The minimum glow voltage of lamp I4 is such that the voltage across its terminals is insufiicient to cause it to glow when the lamp I0 is operating so that it is out of the circuit. For example, where the source I2-I2 is a 115-volt alternating current line and the lamp I0 is one of the low-pressure fluorescent type recently made commercially available having an operating voltage of about 65 volts, the glow lamp I4 may be one having a minimum glow voltage of about 7'7 volts. For

higher voltage lamps I0 operating from a 220 volt line, the glow lamp I4 may have a minimum glow voltage of about 160 volts. That is, the glow lamp I4 is designed to operate and pass current at line voltages to permit the switch IE to shunt it, thus causing heating of electrodes lI--II and a surge which starts lamp I0, the voltage across said lamp I0, after starting, be-

ing insufficient to actuate the glow lamp circuit.

The Fig. 2 circuit is similar to that shown in Fig. 1 except that the switch or relay 2| shown saidv lamp l0, after starting, being insufficient to actuate the glow lamp vibrator circuit.

The circuits described above may be operated from a source of direct current, if desired. In that case only one of the electrodes I l or I! need be heated for starting. For example, the electrode (anode) ll may, in, that event, have a single lead-in wire connected to both the terminal I2 and the glow lamp l4, and a series ballast resistance may be added to, orsubstituted for, the

choke coil I3.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In combination, a gaseous electric discharge lamp device containing at least one thermionic cathode and a cooperating electrode, and a starting and operating circuit therefor comprising an inductance, means connecting one end of said thermionic cathode and said cooperating electrode across the terminals of a current source in series with said inductance, a glow discharge device connected across the opposite end of said thermionic cathode and said electrode, a relay comprising actuating means connected in series with said glow discharge device across said discharge lamp device and normally open contacts connected in a shunt circuit across said actuating means and said glow discharge device, the said 2. In combination, a gaseous electric discharge lamp device containing at least one thermionic cathode and a cooperating electrode, and a starting and operating circuit therefor comprising an inductance, means connecting one end of said thermionic cathode and said cooperating electrodeacros s the terminals of a current source in series with said inductance, a glow discharge device connected across the opposite end of said thermionic cathode and said electrode, a relay comprising a magnetic coil and normally open contacts actuated thereby, saidmagnetic coilbeing in series with said glow discharge device across said discharge lamp device, and said contacts being connected in ,a shunt circuit acrosssaid magnetic coil and said glow discharge device, the said glow discharge device being operative upon closing of the circuit across said current source to cause said relay to be actuated but being inoperative upon the starting of said discharge lamp device.

3. In combination, a gaseous electric discharge lamp device containing at least one thermionic cathode and a cooperating electrode, and a starting and operating circuit therefor comprising an inductance, means connecting one end of said thermionic cathode and said cooperating electrode across the terminals of a current source in series with said inductance, a glow discharge device connected across the opposite end of said thermionic cathode and said electrode, a relay comprising a resistance heater and normally open contacts including a bimetallic element actuated by said heater, the said resistance heater being in series with said glow' discharge device across said discharge lamp device, and said consaid resistance heater and said glow discharge device, the said glow discharge device being operative'upon closing of 'the circuit across said current source to cause said relay to be actuated but being inoperative upon starting of said discharge lamp device.

LEO R. PETERS.