JP2538291B2 - Ballast for discharge lamp - Google Patents

Description

TECHNICAL FIELD The present invention relates to a ballast for a discharge lamp having an improved winding structure.

[Conventional technology]

In the leakage transformer type ballast for discharge lamps,
As shown in FIG. 3, the primary coil 1 and the secondary coil 2
As shown in the circuit diagram of FIG. 4, a protective device 8 such as a thermal fuse or a thermal protector is added to the power supply side of the ballast as a means for protecting the coil from overheating. Alternatively, a low melting point insulated wire is used for the primary coil 1 and the secondary coil 2, and a protection means is used for cutting the circuit by melting when the coil becomes high temperature.

[Problems to be solved by the invention]

Among the above-mentioned conventional techniques, the method of adding a protection device requires that a protection device that is not directly related to the lighting of the discharge lamp be prepared separately, and the method of using the low melting point insulated wire is that the primary coil is blown out. However, since the secondary coil may remain as a kind of choke coil, the discharge lamp may remain lit in some cases, and there is a risk that the abnormal state may not be noticed.

According to the present invention, the primary coil and the secondary coil are melted at the same time at the time of abnormality without using a special protection device,
It is an object of the present invention to obtain a ballast for a discharge lamp capable of preventing smoke and ignition.

[Means for solving problems]

The purpose is to use a low-melting point insulated wire for the windings of the primary coil and the secondary coil, and to use a part of the secondary coil as described above.
This is achieved by winding on the next coil.

[Action]

In the ballast for a discharge lamp according to the present invention, a part of the secondary coil also made of the low melting point insulated wire is wound on the primary coil wound with the low melting point insulated wire.
When an abnormality occurs in the secondary coil and the current increases and the temperature becomes high, a part of the secondary coil wound on the primary coil also becomes high in temperature. Therefore, the primary coil and the secondary coil are different from each other. It blows out almost at the same time, and smoke and ignition of the ballast can be prevented.

〔Example〕

 Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view showing an embodiment of a discharge lamp ballast according to the present invention, and FIG. 2 is a circuit diagram of the above embodiment. In FIG. 1, the secondary coil 2 is divided into a secondary coil 3 on the primary coil 1 and a secondary coil 4 as a secondary winding.
The secondary coil 3 on the secondary coil 1 was wound around the primary bobbin 5 after winding the primary coil 1 with an insulator 7 having good thermal conductivity interposed therebetween. As a result, when the primary coil 1 becomes abnormal and its temperature rises, heat is also conducted to the secondary coil 3 wound on the upper side, and the coils 1 and 3 can be melted at almost the same time. Is.

Further, the secondary coil 3 on the primary side is positively wound as shown in FIG. 2, and the primary coil 1 is wound 760 times as shown in Table 1.
The secondary side secondary coil 3 is wound 42 times and the secondary side secondary coil 4 is wound 89 times.
If you wind it 6 times, As shown in Tables 2 and 3 below, the discharge lamp ballast of this embodiment has a tube current ratio higher than that of the conventional example. The ratio of the tube power to the tube power was about 3.4%, and the input power factor to the tube power was about 2.4%. It was possible to improve the electrical characteristics.

〔The invention's effect〕

As described above, the discharge lamp ballast according to the present invention is a discharge lamp ballast including a primary coil and a secondary coil,
Since a low melting point insulated wire is used for the primary coil and the secondary coil and a part of the secondary coil is wound on the primary coil, a protection device such as a temperature fuse is not required, and Since the secondary coil and the secondary coil can be melted and blown almost at the same time due to an abnormal temperature rise, smoke and ignition of the discharge lamp ballast can be prevented in advance.

[Brief description of drawings]

1 is a sectional view showing an embodiment of a discharge lamp ballast according to the present invention, FIG. 2 is a circuit diagram of the above embodiment, FIG. 3 is a sectional view showing a conventional discharge lamp ballast, and FIG. FIG. 1 is a circuit diagram showing the above conventional protection device. 1 ... Primary coil, 2, 4 ... Secondary coil, 3 ... Secondary coil on the primary coil.

Claims (1)

(57) [Claims] 1. A ballast for a discharge lamp comprising a primary coil and a secondary coil, wherein a low melting point insulated wire is used for the primary coil and the secondary coil, and a secondary wire is provided on the primary coil. A ballast for a discharge lamp characterized by winding a part of a coil.