JPS5916299A - High voltage sodium lamp unit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high-pressure sodium lamp device that combines a light-transmitting arc tube with an inductance ballast for lighting a high-pressure sodium lamp in which sodium and a rare gas for starting aid are sealed.

High-pressure sodium lamps are about twice as efficient as conventional high-pressure mercury lamps, and because of the warm and desirable color of the casing, they can be used not only for outdoor lighting but also for some indoor lighting such as in the factory gymnasium. Because of its applicability, it is attracting attention as an energy-saving light source that can replace high-pressure mercury lamps.

However, a practical problem with this high-pressure sodium lamp compared to a high-pressure mercury lamp is that its starting voltage is high. In other words, in order to maximize efficiency, high-pressure sodium lamps are usually filled with xenon as a rare gas for starting aid, which has low thermal conduction loss in the arc tube, and as a result, the starting voltage of the lamp is 180 V, which is the starting voltage of a high-pressure mercury lamp. The voltage is about 2KV or higher compared to the voltage below. Therefore, while high-pressure mercury lamps can be started with the 200'V AC power supply voltage itself and operated with a simple single-choke type ballast, high-pressure sodium lamps can be lit using a dedicated starting device that operates during normal starting. ballasts are used.

On the other hand, connect a bimetal switch in parallel to the arc tube,
Some high-pressure sodium lamps, which start the lamp by using the so-called kick voltage induced in the inductance ballast when the current is interrupted by a bimetallic switch, have also been put into practical use. Similarly, it can be lit with a single choke type ballast without a built-in starting device, but the kick voltage can sometimes become abnormally high, which can cause problems with the electrical insulation of the ballast and tube light circuit, especially when the lamp is defective. There is a problem with it being destroyed.

An object of the present invention is to provide a high-pressure sodium lamp device that can be safely lit with a choke-type ballast in the same way as with a mercury lamp.

The present inventor conducted a detailed study on a starting method that can safely and easily light a high-pressure sodium lamp. the result,
To suppress abnormally high kick voltage caused by thermally responsive switches such as Imetal switches (connected in parallel to the arc tube), it is possible to safely and easily It has been found that a high-pressure sodium lamp that can be started quickly is realized.The present invention will now be described in detail based on an embodiment shown in the drawings.

FIG. 1 shows the arc tube structure of the lamp used in the study of the present invention. 1 is a light-transmitting luminous tube made of a polycrystalline alumina ceramic tube or a single crystal alumina tube, and end caps 2 and 3 made of alumina ceramic are attached to both ends of the tube.
is sealed with ceramic cement, and the end cap 2゜3 has niobium tubes 4 and 5 as current introducing bodies.
are each sealed. At the tips of the niobium tubes 4, 6, electrodes 6, 7 made of tungsten coils filled with an electron emitting material are held. In addition to sodium, which is a luminescent substance, the arc tube 1 is filled with mercury, which acts as a buffer gas, and a rare gas to assist in starting. As a lamp, such an arc tube is held within an evacuated outer envelope.

The inventor first studied a system in which a series body of a resistor 9 and a bimetal switch 1o was connected in parallel to an arc tube 8, as shown in FIG. Here, the resistor 9 has a function as a heater that opens the bimetal switch 10 by heating, and also functions to limit the current value in lamp types in which the bimetal switch 1o requires a large interrupting current. Although this method itself is already known, as a result of studies conducted by the present inventors, it was observed that even if the interrupting current was limited by the resistor 9, an abnormally high kick voltage was generated in the inductance ballast 11. For example, when a high-pressure sodium lamp designed to be lit with a single-choke type ballast for a 400W high-pressure mercury lamp is started using the method shown in Figure 2, the interrupting rated current of the lamp is reduced to 0.8A by resistor 9. However, an abnormally high kick voltage of 7 to 11 KV occurred.

The inventor then studied a method for suppressing the abnormal voltage as described above, and as a result, as shown in FIG.
xide Non1inear Re5istor)
It has been found that it is effective to connect a surge absorber element 12 such as the following. However, since this element is not a negative resistance element like a normal Zener diode, the input voltage Vin is clipped with the output voltage Vout by the surge absorber element 12 as shown in FIG. The voltage can be limited to a voltage value below that specified by this element.

Based on the present invention, the distance between the electrodes is 83 mm with a pipe inner diameter of 7.4 mm.
Using an alumina arc tube with tube dimensions of rrun,
A 360W lamp was manufactured in which 4.5 Torr of sodium, 209 Torr of mercury, and 350 Torr of xenon were sealed in the tube. As shown in FIG. 6, inside the outer tube 16, a resistor 9 (defined as a steady-state interrupting current of 0.8 A) and a bimetal switch 1o are connected in series in parallel to the arc tube 8.

A ZNR element is connected as a surge absorber element 12 in parallel to the lighting inductance stabilizer 11 .

The ZNR element used has a varistor voltage (voltage between both terminals when 1 mA of DC is applied to the ZNR element, and the current begins to increase rapidly at a value higher than this varistor voltage) of 4 KV and an energy withstand capacity of 10 Joule. Furthermore, since the xenon filling pressure is high in this lamp, a starting auxiliary conductor 13 consisting of a molybdenum wire with a wire diameter of 7 mm to which one electrode potential is applied is attached to the outer wall of the tube along the entire length of the tube. In order to prevent the starting auxiliary conductor 13 from disappearing, the starting auxiliary conductor 13 is connected to the electrode via a bimetallic switch 14 which is opened by heat radiation from the arc tube after the lamp is lit.

The starting voltage of such a 5eoW high pressure sodium lamp is 3.
Since the kick voltage applied to the arc tube was limited to approximately 5.3 KV or less, the lamp was reliably started within six openings of the bimetallic switch 12. Furthermore, it has been confirmed that the safety of the ballast and tube light circuit can be sufficiently guaranteed even with the lamp's acing system.

Note that other surge absorber elements, such as SiC
The ZNR element showed the best results.

In addition, the lamp efficiency of such a 360W lamp is approximately 1351.
m/W and the lamp voltage and current are each 13
It was lit at 0■ and 3.3A.

As explained above, compared to conventional high-pressure sodium lamps, the present invention is easier to start and guarantees the safety of the ballast and lamp circuit. It is possible to provide a high-pressure sodium lamp device that has advantages such as being able to be safely lit at low temperatures.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of the arc tube of a high-pressure sodium lamp, Figure 2
The figure is a side view of a circuit for consideration of a lighting device using the same arc tube, Figure 3 is a circuit diagram of a high-pressure sodium lamp that is an embodiment of the present invention, Figure 4 is a diagram explaining the function of a surge absorber element, FIG. 6 is a circuit diagram of a high pressure sodium lamp which is another embodiment of the present invention. 1... Arc tube, 6, 7... Electrode, 10
... Bimetal switch, 11 ... Inductance stabilizer, 12 ... Surge absorber I. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 4: Figure 4 ----------

Claims (2)

[Claims] (1) A series body consisting of a resistor and a thermally responsive switch is connected in parallel to the arc tube of a high-pressure sodium lamp in which sodium and a rare gas for starting aid are sealed in the light-transmitting arc tube, and further A high-pressure sodium lamp device characterized in that a lighting inductance ballast and a diapsoba element are connected in parallel. (2) The high-pressure sodium lamp device according to claim (1), wherein the surge absorber element is comprised of a zinc oxide varistor element.