JPS6310640Y2 - - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a discharge lamp lighting device.

Conventionally, a single-turn leakage transformer has been used as a phase-advanced, high-power-factor ballast, but this ballast is a single-turn type with a primary winding and a secondary winding connected in series. Therefore, the voltage across the series circuit of the primary winding and the secondary winding is applied to both ends of the discharge lamp, but this method has disadvantages such as the high secondary voltage, which shortens the life of the discharge lamp. In order to compensate for this drawback, the secondary voltage was adjusted by reducing the number of turns in the secondary winding, but the reduction in the number of turns reduced the inductance component in the lighting circuit, causing flickering at low temperatures. There is a problem that the lamp current waveform deteriorates. Therefore, what has been proposed in the past is the circuit configuration shown in Figure 1, in which the secondary winding S of the ballast 1 is
It is connected to approximately the center point N of the next winding P. The ballast 1 has one end of the primary winding P connected to an AC power supply 3 via a thermal protector 2, and further has a preheating winding h ₂ with the ground end of the primary winding P and one end commonly connected.
is connected to one filament f ₂ of the discharge lamp 4, and one end of the secondary winding S is connected to the other filament f ₁ via a parallel circuit of a phase advance capacitor 5 and a discharge resistor 6, and the other A preheating winding h ₁ is connected to the filament f ₁ . Note that 7 is a capacitor for noise prevention.

By the way, in this discharge lamp lighting device, by taking out the secondary winding S of the ballast 1 from the center point N of the primary winding P, it is possible to eliminate the reduction in inductance component when optimizing the secondary voltage. However, as the winding process became more mechanized, it became a serious manufacturing problem to extract the tap from the center point N of the primary winding P of the ballast 1. Immediately stopping the rotation of the winding machine in the middle of winding and processing the lead wire for the intermediate tap requires the structure of the winding machine to become complicated, and also requires human intervention in the process, which is intended to be automated. Not only that, but productivity also dropped significantly.

This invention was created in view of the above-mentioned drawbacks.
The purpose of this is to make use of the same circuit advantages as the circuit shown in Figure 1, eliminate the drawbacks in the winding process, and create a discharge lamp that is safe and highly reliable in the event of trouble. To provide lighting devices.

The present invention will be explained below using examples. FIG. 2 shows a circuit of an embodiment, in which a primary winding P of a ballast 1 consisting of a leakage transformer is connected to an AC power supply 3 via a thermal protector 2, and the primary winding P and A series circuit of a capacitor 8 and a capacitor 9 having the same capacitance is connected in parallel to the series circuit with the thermal protector 2. One end of the secondary winding S of the ballast 1 is connected to the connection point N' between both capacitors 8 and 9, and the other end is connected to one filament f ₁ of the discharge lamp 1. Ballast 1 has a preheating winding h ₁ ,
_h2 are connected to filaments _f1 and _f2 , respectively, and the ground end of the primary winding P is connected to one end of filament _f2 . 10 is a discharge resistance of the capacitor 9.

Now, assuming that the AC power supply 3 is turned on and the discharge lamp 4 is not lit up, the connection point between the capacitors 8 and 9
A voltage of 1/2 of the power supply voltage is applied to N'. That is, a voltage similar to the voltage at the center point N of the circuit of FIG. 1 is generated in the secondary winding S. And this voltage and the primary winding P
The voltages are added together and applied to the discharge lamp 4, and the discharge lamp 4 is started and lit.

After the discharge lamp 4 is turned on, the current flowing through the capacitor 8 is the vector sum of the current flowing through the secondary winding S to the discharge lamp 4 and the current flowing toward the capacitor 9, and is different from the current flowing through the capacitor 9. Therefore, measures have been taken to differentiate the capacitors 8 and 9 in terms of withstand voltage. Further, the capacitor 8 has a protection device or a protection function that opens in an abnormal state.

Next, the operation of the safety function of the discharge lamp lighting device of the present invention will be explained. The thermal protector 2 turns off when the device overheats, but even if you turn it on and off now, the capacitors 8 and 9 will still be turned off.
is connected to the AC power supply 3 side rather than the thermal protector 2, so there is no risk of the contacts being welded by the current rushing into the capacitors 8 and 9. When the thermal protector 2 is turned off due to an abnormality in the device, depending on the type of load and power supply voltage, the AC power supply 3, capacitor 8, secondary winding S, discharge lamp 4, and AC power supply 3 may be turned off. The discharge lamp 4 continues to light in a closed circuit, and not only cannot overheating be completely prevented, but also may cause ignition and smoke if the secondary winding S is abnormal. However, the temperature around the capacitors 8 and 9 housed in the same case (not shown) also rises, causing deterioration and destruction of the capacitors 8 and 9, and at this time, the capacitor 8 opens due to its protective device or function. As a result, the aforementioned closed circuit can also be broken.

Furthermore, if an abnormality occurs in the capacitors 8 and 9 first and the capacitor 8 opens before the thermal protector 2 is turned off, the circuit configuration will be as shown in Figure 3, and the voltage applied to the discharge lamp 4 before lighting will be is only the voltage generated in the secondary winding S, and even if the discharge lamp 3 were to light up with that voltage, the output would be reduced by the amount that the secondary voltage had become lower, and not only would it operate on the safe side, but the circuit would Even if an abnormality occurs, the thermal protector 2 operates in the same way as a normal discharge lamp lighting device, thereby helping to detect the abnormality. If the thermal protector 2' is inserted in the position indicated by the broken line in FIG. 2, the lighting of the discharge lamp 4 due to the closed circuit formed when the thermal protector 2 is turned off can be prevented, making it a complete safety measure. Incidentally, since the noise prevention capacitor 7 is connected to the capacitors 8 and 9 with large capacitance on the power supply side, trouble is unlikely to occur even if it is not particularly used.

This invention is a ballast consisting of a leakage transformer.
The secondary winding is connected to an AC power supply via a thermal protector, and a series circuit of two capacitors of approximately equal capacitance is connected in parallel to the series circuit of the thermal protector and the primary winding. Connect one end of the winding to the connection point of both capacitors above,
Since a discharge lamp is connected between the other end of this secondary winding and the ground end of the primary winding, an intermediate tap is provided in the primary winding, and the secondary winding is connected to this intermediate tap. The same effect as a conventional ballast with one end connected can be obtained without providing an intermediate tap on the primary winding of the ballast, and since there is no need to provide an intermediate tap, the winding can be automated and the This has the advantage of eliminating the need for personnel to take out the tap lead wires and improving productivity.Furthermore, since the thermal protector is not connected to the charging path of the capacitor, there is no risk of contact welding due to inrush current. First, it has the advantage of not impairing its own function.

In addition, by using a capacitor that opens in the event of an abnormality in the capacitor that connects one end to the non-grounded end of the primary winding and the same polarity side of the AC power supply, a thermal protector can be used in the event of an abnormality in the capacitor or stabilizer. Even if an abnormality occurs again in the closed circuit caused by the insertion position of the thermal protector after the thermal protector is turned off, the circuit can be interrupted by opening the capacitor, and the secondary winding can be connected to the circuit in parallel with the primary winding. By connecting it, a circuit can be configured on the safe side to reduce the output.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of a conventional example, Fig. 2 is a circuit diagram of an embodiment of the present invention, and Fig. 3 is a circuit diagram for explaining the operation of the same. is an AC power supply, 4 is a discharge lamp, P is a primary winding,
S is a secondary winding.

Claims (1)

[Claims for Utility Model Registration] (1) The primary winding of a ballast consisting of a leakage transformer is connected to an AC power source via a thermal protector, and a series circuit of two capacitors with approximately equal capacitance is connected to the thermal Connect in parallel to the series circuit of the protector and the primary winding, connect one end of the secondary winding of the ballast to the connection point of both capacitors, and connect the other end of this secondary winding to the connection point of the primary winding. A discharge lamp lighting device consisting of a discharge lamp connected between both ends and a grounded end. (2) A capacitor that opens in the event of an abnormality is used as a capacitor whose one end is connected to the non-grounded end of the primary winding of the ballast described in claim 1 of the utility model registration claim and the same polarity side of the AC power source.