JPH0351919Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a discharge lamp lighting device that lights an even number of discharge lamps using the high frequency output of a transistor inverter.

<Prior art> In a lighting device that uses a transformer in which the primary and secondary windings are coupled as a single-turn type oscillation transformer for such a transistor inverter, the discharge lamp is turned off by removing it to cut off the power supply. Electrical equipment standards laws require that a safety interlock switch be installed in the lamp socket. Therefore, in a lighting device in which, for example, two discharge lamps are connected in parallel to the secondary high-voltage winding of an oscillation transformer, if one of the discharge lamps is removed for the purpose of saving energy, the interlock switch will operate and the power will be cut off. The other discharge lamp also goes out.

<Problems to be solved by the invention> Therefore, by using an isolation transformer as an oscillation transformer and removing the interlock switch from the lamp socket, it is possible to remove one of the discharge lamps when it is not necessary to light all the lamps. It is possible to try to save electricity. However, for example, if one discharge lamp is removed from a device in which two discharge lamps are connected in parallel, the oscillation frequency of the inverter will decrease due to the decrease in the load on the oscillation transformer.
The impedance of the entire circuit decreases, and overcurrent flows through the remaining discharge lamp and circuit elements, which adversely affects the life of the discharge lamp and causes troubles such as damage to the circuit elements.

Therefore, the present invention aims to provide a discharge lamp lighting device that can reliably prevent overcurrent from flowing and reduce power consumption when one of the two discharge lamps is removed. This is an issue to be addressed.

<Means for Solving the Problems> In the present invention, as a technical means for achieving the above-mentioned problems, a discharge lamp lighting device is configured as follows. That is, in a discharge lamp lighting device that drives a transistor inverter by supplying direct current power obtained by rectifying commercial alternating current, and lights discharge lamps connected as a pair to the secondary high voltage winding of an oscillation transformer of this inverter, An insulation type transformer is used as the oscillation transformer, and two chiyoke coils are inserted and connected in series between the two discharge lamps and the secondary high voltage winding, respectively, and for mounting each of the discharge lamps. The lamp is equipped with two changeover switches that are turned on and off when the discharge lamp is connected to and removed from the socket, and the changeover switch turns off the discharge lamp when one discharge lamp is removed, and the changeover switch turns off the discharge lamp when one discharge lamp is removed. The above-mentioned connected coils are connected to each other so as to be switched from a low inductance including zero during steady lighting to a predetermined high inductance.

<Function> When one of the discharge lamps in a set is removed, the changeover switch of the mounting socket of this discharge lamp is turned off, and the switch coil connected in series to the other discharge lamp is switched off. The low inductance including zero during steady lighting is switched to a predetermined high inductance. Therefore, even if the oscillation frequency of the inverter decreases, the series inductance of the remaining discharge lamps increases, and the impedance of the circuit is maintained at approximately the same value as when two lamps are lit.
No overcurrent will flow through the discharge lamp or circuit elements.
Further, no current flows through the discharge circuit of the discharge lamp that has been removed, and the series inductance of the remaining discharge lamp increases, so that power consumption decreases as the discharge lamp is removed, resulting in power savings.

<Example> Hereinafter, preferred examples of the present invention will be described in detail with reference to the drawings.

In FIG. 1 showing an embodiment of the present invention, commercial AC from a commercial AC power source 1 is full-wave rectified by a full-wave rectifier circuit 2 and converted to DC power, and this DC power is transmitted through transistors 3 and 4 and a resistor. A transistor inverter is configured as an oscillation circuit by an electronic circuit 5 consisting of a capacitor, etc., and an isolated oscillation transformer 6 consisting of a primary winding 7, an auxiliary winding 8, and a secondary high voltage winding 9. The high frequency output of this inverter drives the oscillation transformer 6.
A pair of discharge lamps 14 and 15 connected in parallel to the secondary high-voltage winding 9 are turned on.

Between the secondary high-voltage winding 9 and each of the discharge lamps 14 and 15, a chiyoke coil 10 and 12 are inserted and connected in series, respectively. The inductance between the respective one-end taps S, V connected to the secondary side high-voltage winding 9 and the intermediate taps T, W of each of the choke coils 10 and 12 is set to the inductance during steady lighting. A changeover switch 1 is provided between each of the other end taps U and X connected to each discharge lamp 14 and 15, respectively, and each intermediate tap T and W.
1 and 13 are connected to each other. The respective changeover switches 11 and 13 are connected to the discharge lamp 1 on the side to which the corresponding switch coils 10 and 12 are not connected.
When 5 and 14 are removed, the switch is turned off. That is, as shown by the broken line in the figure, when one discharge lamp 14 is removed, the other changeover switch 1
3 is opened as shown, and when the other discharge lamp 15 is removed, one changeover switch 11 is opened as shown. Therefore, when both the discharge lamps 14 and 15 are installed in the mounting sockets as shown in the figure, both the changeover switches 11 and 13 are closed contrary to the state shown in the figure, and a part of each of the choke coils 10 and 12 is closed. However, for ease of explanation hereinafter, the changeover switches 11 and 13 are shown in opposite states.

Next, the aforementioned changeover switches 11 and 13 will be explained with reference to FIG. These changeover switches 11, 13
The movable piece 21 and the fixed piece 22 are arranged oppositely with the contact portions provided at the tips of each piece facing each other, and the movable piece 21 is made of an elastic metal such as phosphor bronze. Normally, the shape is slightly curved upward in the figure, but as shown in the figure, the discharge lamp 1
4 and 15 are attached to the mounting socket, the discharge lamps 14 and 15 press the fixed piece 22 side, and both contact portions come into contact with each other in an electrically conductive state as shown in the figure. When the discharge lamps 14 and 15 are removed, the movable piece 21 returns to its original state and the contact portions are separated. Each of the changeover switches 11 and 13 can be built into one of a pair of mounting sockets to which the discharge lamps 14 and 15 are respectively mounted. That is, the isolated oscillation transformer 6
By using this, it is possible to use the existing interlock switch, which is no longer necessary. Note that both terminals Y and Z of the changeover switches 11 and 13 are connected to each of the switch coils 1 in FIG.
Of course, the other ends of the pins 0 and 12 are connected to the taps U and X.

Next, the operation of the above embodiment will be explained. When both the discharge lamps 12 and 15 are attached together, the changeover switches 11 and 13 are both closed and a part of each of the switch coils 10 and 12 is short-circuited, and each switch coil 10 and 12 is Each discharge lamp 14, as the inductance during steady lighting between taps S, V at one end and taps U, X at the middle, respectively.
15 in series. Therefore, each discharge lamp 1
The discharge currents of Nos. 4 and 15 are maintained at the rated values.

For the purpose of saving electricity, for example, one of the discharge lamps 1
4, the inductance of the stationary coil 12 connected in series to the other remaining discharge lamp 15 increases to a value between the taps V and X, which is larger than that during steady lighting due to the opening of the changeover switch 13. Therefore, even if the oscillation frequency of the inverter decreases due to a decrease in the load on the oscillation transformer 6, the series inductance of the other discharge lamp 15 increases, so that the impedance of the circuit itself remains approximately at the same value. Therefore, the current in the discharge circuit of the discharge lamp 15 can be maintained at approximately the rated value. Further, no current flows through the discharge circuit of one discharge lamp 14, and the series inductance of the other discharge lamp 15 increases, so that power consumption decreases as the discharge lamp 14 is removed.

FIG. 3 shows another embodiment of the present invention, and in this figure, the same or equivalent parts as in FIG. And, corresponding to each discharge lamp 14, 15, it is divided into an insulated oscillation transformer 6 having windings 7 to 9 and an insulated oscillation transformer 6a having windings 7a to 9a,
A discharge lamp 1 is individually connected to each secondary high voltage winding 9, 9a.
4 and 15, and a discharge circuit including these coils 10 and 12. Since the discharge circuits of the discharge lamps 14 and 15 are thus independent, if the oscillation transformers 6 and 6a are of the leakage flux type, there is no need to provide the chiyoke coils 10 and 12 in each discharge circuit. Therefore, the changeover switches 11 and 13, which are closed when the discharge lamps 14 and 15 are installed, short-circuit the entirety of each of the switchover coils 10 and 12, respectively, and the changeover switches 11 and 13, which are opened when the discharge lamps 14 and 15 are removed, short-circuit each of the switchover coils 10 and 12, respectively. , 12 are all interposed and connected to the discharge circuit,
It is possible to obtain the same effects as in the above embodiment.

Note that the number of discharge lamps 14 and 15 is not limited to two, and an even number of two discharge lamps can be lit as a set.

<Effects of the invention> As described above, according to the discharge lamp lighting device of the invention, when one of the discharge lamps in a set of two is removed as necessary, the switch that is automatically switched by the removal Overcurrent can be reliably prevented to protect remaining discharge lamps and circuit elements, and power consumption can be reduced by the amount of removed discharge lamps. Moreover, it has the advantage that it can be achieved with a simple configuration that uses an existing interlock switch.

[Brief explanation of the drawing]

Fig. 1 is an electrical circuit diagram of one embodiment of the present invention;
The figure is a side view of the changeover switch, and FIG. 3 is an electric circuit diagram of another embodiment of the present invention. 1...Commercial AC power supply, 6, 6a...Isolated oscillation transformer, 9, 9a...Secondary side high voltage winding, 10,
12... Chiyoke coil, 11, 13... Changeover switch, 14, 15... Discharge lamp.

Claims (1)

[Scope of utility model registration request] In a discharge lamp lighting device that drives a transistor inverter by supplying DC power obtained by rectifying commercial AC, and lights discharge lamps connected as a pair to the secondary high-voltage winding of the oscillation transformer of this inverter, an isolated type A transformer is used as the oscillation transformer, and two chiyoke coils are inserted and connected in series between the two discharge lamps and the secondary high-voltage winding, respectively, and are connected to the mounting sockets of each of the discharge lamps. and two changeover switches that are turned on and off by attaching and detaching the discharge lamp, and the changeover switch turns off the discharge lamp when one discharge lamp is removed, and connects both the York coils and the changeover switches to the other discharge lamp. A discharge lamp lighting device characterized in that the chiyoke coils are interconnected and connected so as to switch from a low inductance including zero during steady lighting to a predetermined high inductance.