JPH0311835Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) This invention relates to a discharge lamp lighting device for sequentially lighting two or more rabbit-start type discharge lamps.

(Prior art) For example, to sequentially light two discharge lamps, one of the first and second discharge lamps connected in series, for example, a capacitor for sequential lighting in parallel to the first discharge lamp. It is known to connect and configure. With this configuration, when starting lighting, the first discharge lamp is short-circuited by the capacitor, so that the starting voltage is applied to the second discharge lamp via the capacitor, and this voltage is applied to the second discharge lamp through the capacitor. The application causes a slight discharge current to flow through the second discharge lamp. Then, a starting voltage is applied to the first discharge lamp via the second discharge lamp, and a slight discharge current begins to flow in the first discharge lamp as well.
After passing through such a state, both discharge lamps shift to a lighting state.

Such sequential lighting means is already well known, and it is also known that this slight discharge current becomes smaller as the restriking voltage of the discharge lamp becomes higher. On the other hand, power-saving discharge lamps have recently come into widespread use. However, this type of discharge lamp has a higher re-ignition voltage than a general discharge lamp at low temperatures. Therefore, for the above-mentioned reasons, the slight discharge current at the time of starting becomes small, and the discharge state becomes stable while remaining a slight discharge, resulting in a phenomenon that the lighting state does not change.

In order to prevent such a situation from occurring, the slight discharge current at the time of starting may be increased. As a means for this purpose, a method has been considered in which a capacitor with a large capacity is used as the capacitor for sequential lighting to reduce the impedance at the time of starting. However, such a method is not very desirable since it has a negative effect on the life of the discharge lamp, and also has the drawback of increasing the price.

(Problems to be solved by the invention) The purpose of this invention is to make it possible to increase the slight discharge current by simply changing the structure.

(Means for solving the problem) This idea prevents the pass core from being saturated by using a magnetic steel plate with high saturation magnetic flux density as the pass core through which the leakage magnetic flux of the leakage transformer that constitutes the ballast passes. It is characterized by

(Function) The path core of a normal leaky transformer of this type has a small cross-sectional area, so it is likely to be in a state of magnetic saturation. As a result, the leakage inductance is small, resulting in a large impedance at startup. However, in order to prevent the pass core from becoming saturated, we used a magnetic steel plate with a higher saturation magnetic flux density than conventional ones, such as a grain-oriented electrical steel plate, which increased the leakage inductance, which reduced the impedance at startup and caused a slight discharge current. will begin to increase.

(Example) This invention will be explained with reference to a diagram. Reference numerals 1 and 2 represent first and second discharge lamps, which are connected in series as shown in the diagram. Reference numeral 3 denotes a leakage transformer constituting a ballast, which is equipped with primary and secondary coils 4 and 5, and has a T-shaped core 6 and two T-shaped cores 7 to form a sun-shaped shape. It is composed of assembled iron cores 8 (see Fig. 2). 9 is a bridge gap formed on the center leg of the iron core 6; 10 is a bridge gap formed between both the coils 4 and 5 wound around the center leg;
This is the path score that exists between them. 11 is a phase advance capacitor, 12 is a noise prevention capacitor, and 13 is a sequential lighting capacitor, which are connected in parallel to one, for example, the first discharge lamp. A series circuit of both discharge lamps 1 and 2 is connected to an output end of a leakage transformer 3. 14 is a coil for heating the filament.

The above configuration is not particularly different from conventional devices of this kind, but according to this invention, a magnetic steel plate with a high saturation magnetic flux density, such as a grain-oriented electrical steel plate, is used as the pass core 10, and the pass core 10
Make sure that 0 does not become saturated. The path core of a normal leaky transformer 3 of this type has a narrow cross-sectional area and is likely to be magnetically saturated, but in order to prevent this from becoming saturated, this invention is constructed as described above.

In the above configuration, if the primary coil 4 is now connected to the lighting power source, the magnetic flux induced by the secondary coil 5 will be
0, passes through gap 15. As described above, in the past, the path core 10 was saturated by this magnetic flux. However, in the configuration shown in the figure, the saturation magnetic flux density of the path core 10 is set to be large, so the path core 10 will not be saturated.
Since the path core 10 is not saturated in this way, the leakage inductance becomes larger than when it is saturated. As a result, the impedance at the time of starting becomes small, so that the slight discharge current at this time increases sufficiently. Therefore, even when using a power-saving discharge lamp, the difficulty of starting at low temperatures can be easily solved.

In addition, as the grain-oriented electrical steel sheet used in this invention, one having a magnetic flux density of about 19,000 Gauss or more is suitable. Incidentally, the saturation magnetic flux density of the conventional one is approximately
It is about 17,000 Gauss.

(Effects of the invention) As detailed above, according to this invention, simply using a magnetic steel plate with a high saturation magnetic flux density as a pass core solves the difficulty of sequential starting due to a decrease in the slight discharge current during starting. This has the effect of easily avoiding the problem.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram showing an embodiment of this invention, Figure 2 is a circuit diagram showing an embodiment of this invention.
The figure is a cross-sectional view of the ballast. 1, 2...discharge lamp, 3...ballast, 4...primary coil, 5...secondary coil, 8...iron core, 10...
...pass score.

Claims (1)

[Scope of utility model registration request] A plurality of discharge lamps are connected in series to the output end of a leakage transformer constituting a ballast via a phase advancing capacitor, and a plurality of discharge lamps are connected in parallel to at least one of the discharge lamps for successive lighting. A discharge lamp sequential lighting device comprising a capacitor connected, wherein the pass core of the leakage transformer is made of a magnetic steel plate with a high saturation magnetic flux density so as not to be magnetically saturated when the discharge lamp is started. .