JPH01211896A - High-pressure sodium lamp - Google Patents

Abstract

PURPOSE:To reduce the refiring voltage and prevent flickering and quenching when lighting with a constant-power type ballast by connecting a resistor in series to a luminous tube incorporated in an unsaturation type high-pressure sodium lamp. CONSTITUTION:A luminous tube 2 made of translucent alumina or the like is provided in an unsaturation type high-pressure sodium lamp 1, a small quantity of sodium amalgam to be completely evaporated at the time of the lighting action and inert gas are sealed in it, electrode support tubes 3 made of niobium are fixed to both ends of it. A resistor 4 made of a W filament is connected between one of support tubes 3 and one of lead wires 5 along the luminous tube 2, the resistance value of this resistor 4 is selected to a value corresponding to the power consumption at the time of lighting. One of the lead wires 5 of the lamp 1 is connected to the secondary side 11a of a leakage transformer 11 via a capacitor 12, the other is connected to the primary winding connected to a power source 13. The Q value of a resonant circuit is reduced by the increased loss caused by the resistor 4, the rising of a current is accelerated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a high-pressure sodium lamp that is operated using a constant power ballast that prevents flickering and fading phenomena.

[Conventional technology]

Generally, in a discharge lamp lighting circuit, a constant power type ballast, in which a nonlinear inductance such as a leakage transformer and a capacitor are connected in series to form a resonant circuit, has constant power characteristics against fluctuations in power supply voltage. It is used for such things. However, high-pressure sodium lamps with high brightness have the characteristic that the lamp voltage increases as the input power increases, so stable lighting is achieved using the constant power type ballast, which has the characteristic that the lamp power increases with the lamp voltage. I couldn't make him do it.

By the way, in recent years, so-called unsaturated high-pressure sodium lamps have been proposed, which contain a small amount of sodium and mercury and cause all of the sodium and mercury to evaporate while the lamp is lit.
This unsaturated type high-pressure sodium lamp can be stably lit even with the above-mentioned constant power type ballast.

[Problem to be solved by the invention]

However, when a constant power ballast is used to light the above-mentioned unsaturated high pressure sodium lamp, since the arc tube is elongated, ions inevitably disappear quickly in the discharge space. Due to the circuit characteristics of the C resonant circuit, the rise of the lamp current is slow, so the restriking voltage at the time of starting becomes high, and there is no margin between it and the discharge sustaining voltage. As a result, depending on the design of the constant power ballast, the lamp may flicker or go out.

This phenomenon occurs especially when the ballast is designed so that the discharge sustaining voltage during lighting is close to the restriking voltage, but even a slight distortion of the power supply voltage waveform can cause this phenomenon to become even more pronounced. There is.

The present invention was made in order to solve the above-mentioned problems in high-pressure sodium lamps lit using conventional constant-power ballasts, and it is an object of the present invention to provide a high-pressure sodium lamp that does not flicker or go out. With the goal.

[Means and effects for solving the problems] In order to solve the above problems, the present invention provides lighting using a constant power type ballast in which an inductive controller and a capacitive controller are connected in series to an AC power source. A high-pressure sodium lamp is constructed by connecting a resistor in series with an arc tube.

In a high-pressure sodium lamp configured in this way,
Due to the increase in loss due to the resistor connected in series with the arc tube, the Q value of the resonant circuit in the constant power ballast consisting of an inductive controller and a capacitive controller decreases, and the peak value of the lamp current waveform decreases. However, the current rises faster, the current stop period becomes shorter, and the restriking voltage decreases. Therefore, the difference between the discharge sustaining voltage and the restriking voltage becomes large, which makes it difficult for flickering and fading phenomena to occur, and stable lighting can be achieved.

〔Example〕

Examples will be described below. FIG. 1 is a schematic diagram of an embodiment of an unsaturated high-pressure sodium lamp according to the present invention. In FIG. It is made of synthetic alumina, etc.

The interior of the arc tube 2 is filled with sodium amalgam, inert gas, etc., to the extent that it completely evaporates during lighting operation, and electrode support tubes 3.3 made of niobium are fixed to both ends of the tube. 4 is a resistor made of tungsten filament,
It has a resistance value such that the power consumption when the lamp is lit is 20 W, and is connected between one electrode support tube 3 and one leader wire 5. The resistor 4 and the arc tube 2 are enclosed in an outer bulb 6 to constitute an unsaturated high pressure sodium lamp 1.

Unsaturated high pressure sodium lamp constructed in this way
As shown in FIG. 2, the lamp is lit by being connected to a lighting circuit equipped with a constant power ballast consisting of an inductive controller and a capacitive controller. That is, the leaky transformer 11
Connect the lamp 1 to the secondary side of the
The power supply 13 connected to the primary side is turned on and the secondary voltage of the leaky transformer 11 is applied via the capacitor 12 to start the lamp l. After starting, the secondary coil ll of the leaky transformer 11
The current is limited by the inductance of a and the capacitive impedance of the capacitor 12 to continue lighting.

When the unsaturated high pressure sodium lamp according to the present invention was lit with a lighting circuit using such a constant power ballast,
No flickering or fading phenomena occurred at all. Furthermore, the above phenomenon did not occur even when the power supply voltage was varied by about ±10% or the power supply voltage waveform was distorted and the light was turned on under conditions where flickering was likely to occur.

When the lamp voltage (l) at lamp startup was measured, a waveform as shown by the solid line in FIG. 3 was obtained. Furthermore, in order to compare with the lamp voltage Vj of the lamp according to the present invention, the lamp voltage vl' of a conventional unsaturated high-pressure sodium lamp without a resistor connected was measured, and the waveform shown by the dotted line in FIG. 3 was also obtained. It was done. As can be seen from this waveform diagram, it was confirmed that the restriking voltage was reduced in the lamp according to the present invention.

Furthermore, when the relationship between the lamp voltage Vt and the discharge sustaining voltage V was measured, a waveform as shown in FIG. 4 was obtained in the lamp according to the present invention in which a resistor was connected in series to the arc tube. - In the conventional lamp to which the Mannobu antibody is not connected, waveforms Vl', V,' as shown in FIG. 4 +81 were obtained. As can be seen from these waveform diagrams, in the case of the lamp according to the present invention with a resistor connected, the restriking voltage portion of the lamp voltage Vj decreases, so the difference from the discharge sustaining voltage ■ becomes large. I understand. This proves that orders that cause flickering or fading phenomena are prevented.

Next, we created lamps by connecting resistors that consumed power at various ratios to the rated wattage to the arc tubes of unsaturated high-pressure sodium lamps with various rated wattages, and investigated the conditions under which the flickering phenomenon occurred. As a result of the measurement, the results shown in Table 1 were obtained.

Table 1: In the measurement experiment, 10 lamps were created for each case. If flickering occurred in more than half of the lamps, an is indicated with an O mark.

The presence or absence of flickering was determined visually and by observing light waveforms.

As can be seen from Table 1, flickering does not occur at all in lamps connected to a resistor that consumes 10% or more of power relative to the rated wattage of the lamp. However, increasing the power consumption of the resistors connected in series reduces efficiency. It is necessary to suppress the decrease in efficiency to 25% or less. Therefore, it is appropriate for the resistor connected in series to the arc tube to have a resistance value that consumes about 10% to 13% of the power of the lamp's rated wattage. This makes it possible to effectively prevent the flicker phenomenon without significantly reducing efficiency.

The above measurement experiment was conducted on lamps with a 150W rating and a 220W rating, and the appropriate range of resistors was illustrated based on that. However, the flickering phenomenon is more likely to occur in lamps with a low wattage rating, and with a high lamp rating, such as a 360W lamp. The flicker phenomenon occurs only slightly in lamps such as this, so in such a high watt rated lamp, it is possible to sufficiently prevent the flicker phenomenon even with a resistor whose resistance power consumption is on the order of a few percent.

Conventionally, high-pressure mercury lamps and metal halide lamps have been known to have a resistor made of tungsten filament connected in series with the arc tube. This is used as a safety device to prevent this, and is completely different in character from the series-connected resistor in the lamp according to the present invention. Incidentally, in high-pressure sodium lamps, not only is the emission of ultraviolet light from the arc tube negligible, but in the event that the outer bulb is damaged, the niobium that forms the electrode support tube of the arc tube may be oxidized. Since the lamp goes out in a short time, there is no need for external protection means such as a resistor connected in series.

(Effects of the Invention) As described above based on the embodiments, according to the present invention, a high-pressure sodium lamp is constructed by connecting a resistor in series with an arc tube, so that it is lit using a constant power type ballast. In this case, the restriking voltage can be lowered, and stable lighting can be achieved without flickering or fading phenomena.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing an embodiment of a high-pressure sodium lamp according to the present invention, FIG. 2 is a diagram showing an example of the configuration of a lighting circuit using a constant power ballast, and FIG. Go to Figure 4, a diagram showing the lamp voltage waveform. [81 is a diagram showing a lamp voltage waveform and a discharge sustaining voltage waveform. In the figure, ■ is an unsaturated high-pressure sodium lamp, 2 is an arc tube, 3 is an electrode support tube, 4 is a resistor, and 6 is an outer sphere.

Claims (1)

[Claims] 1. A high-pressure sodium lamp that is lit using a constant power ballast with an inductive controller and a capacitive controller connected in series to an AC power source, and is characterized by a resistor connected in series with the arc tube. High pressure sodium lamp.