JPH0633398U - Discharge lamp lighting device - Google Patents

Abstract

(57) [Abstract] [Purpose] After detecting the slow leak phenomenon and interrupting the current flowing through the discharge lamp, the lamp of the discharge lamp that caused the slow leak is replaced with a new lamp tube for the first time. Electricity is supplied and discharge lamp current is passed. [Configuration] in the vicinity of the inductance element L _1, established a resettable thermal fuse SW ₁ having a normally open contact s _1,
Inductance elements L _1, with connected discharge lamp P with normally closed contacts s ₂ of the relay switch SW ₂ in series with the power source V, resettable thermal fuse SW normally open contacts s ₁ of ₁
And connected in series with the excitation winding L ₂ of the relay switch SW ₂ to the power supply V.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a discharge lamp lighting device, and relates to a technique for ensuring the safety of a discharge lamp lighting circuit until a lamp tube of a discharge lamp having a slow leak is replaced.

[0002]

[Prior art]

 In the discharge lamp lighting device, a phenomenon called "slow leak" occurs in which the gaseous metal in the lamp tube of the discharge lamp suddenly or gradually escapes to decrease the lamp voltage, which causes the impedance to decrease. At this time, the lamp current increases and the inductance element in the ballast excessively heats up, increasing the stress of the inductance.

In order to prevent this, a method of increasing the heat capacity of the inductance element can be considered, but if the heat capacity of the inductance element is increased, the ballast must be designed in a large size, which is not practical. Therefore, as a countermeasure against this, a resettable thermal fuse is conventionally used. FIG. 4 is an electric circuit diagram showing a conventional example of a discharge lamp lighting device using a resettable thermal fuse. 4, in the vicinity of the inductance element L _1, established a resettable thermal fuse SW ₁ having a normally closed contact s _1, the inductance element L _1, connected in series with the discharge lamp P to the power supply V with normally closed contact s ₁ is doing. To explain the operation of this circuit, a slow leak occurs in the discharge lamp P and the current in the inductance element L ₁ increases, which causes the inductance element L ₁ to abnormally generate heat and raise its temperature, and the temperature is set. When the threshold value is exceeded, the normally closed contact s ₁ is opened and the current from the power supply V 1 to the discharge lamp P is cut off. When the circuit is de-energized, the inductance element L ₁ is gradually cooled, and when the temperature thereof drops below the threshold value, the normally closed contact point s ₁ returns to the old position and closes. Electric power is supplied to the discharge lamp P. In addition, in FIG. 4, a portion surrounded by a dotted line shows the discharge lamp fixture H.

[0004]

[Problems to be solved by the device]

However, with such a slow leak prevention measure using the resettable thermal fuse SW ₁ , a slow leak is caused even after the abnormal heat generation of the inductance element L ₁ is detected and the current flowing to the discharge lamp P is cut off. If the discharge lamp P is left as it is without being replaced, the normally closed contact s ₁ is automatically closed when the inductance element L ₁ cools and its temperature drops below the threshold value, and the power is turned on again. A current will flow from V to the discharge lamp P via the inductance element L ₁ and the normally closed contact s ₁ . Since such an operation is repeated thereafter, the discharge lamp P repeats an unnatural blinking state and accelerates the deterioration of the inductance element L ₁ and other circuit elements. There is a problem that the whole life is shortened.

In view of such a problem, the present invention detects a slow leak phenomenon and shuts off the current flowing through the discharge lamp, and then replaces the lamp tube of the discharge lamp in which the slow leak has occurred with a new lamp tube. In this case, the first purpose is to supply the power from the power supply and to allow the discharge lamp current to flow so that the normal lighting operation is performed.

[0006]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the discharge lamp lighting device of the present invention is a discharge lamp lighting device comprising an AC power supply, an inductance element for limiting the current of the discharge lamp, and the discharge lamp, and the It is provided with a first switching means for opening and closing by detecting that the current continues to flow for a certain period of time or more, and is opened by the opening or closing operation of the first switching means, and manually closed. The second switching means is connected in series to the power source together with the discharge lamp.

[0007]

[Action]

 The operation of this device will be described. When an overcurrent for a certain period of time or more flows in the discharge lamp that has caused a slow leak, this overcurrent is detected and the first switching means is operated to open / close, and this operation causes the second switching circuit to open or close the circuit. After replacing the lamp of the discharge lamp that caused the slow leak with a new switching means, manually close it to close the discharge lamp in a normal state.

[0008]

【Example】

An embodiment of the present invention will be specifically described below with reference to the drawings. FIG. 1 is an electric circuit diagram showing a first embodiment of a discharge lamp lighting device of the present invention. In FIG. 1, the same circuit components as those of the electric circuit diagram of FIG. 4 showing the conventional example are designated by the same reference numerals for description. It is similar to the electric circuit diagram of FIG. 4 in that a resettable thermal fuse SW ₁ having a contact s ₁ is installed near the inductance element L ₁ , but in FIG. 4, the contact s ₁ is a normally closed type. In FIG. 1, the contact s ₁ is a normally open type, and when the contact s _{1 of} FIG. 1 is once closed, it has a function of opening the circuit only when a reset button (not shown) is operated. ing.

[0009] Then, the normally open contacts s ₁ of the return type thermal fuse S W ₁ of the first switching means 1, connect the excitation winding L ₂ of the relay switch SW ₂ as the second switching means connection with connected in series to a power source V, and constantly closed type contact point s ₂ of the relay switch SW ₂ that opens and closes the intermittent current flowing through the excitation winding L _2, to the power supply V in series with the discharge lamp L Te To do. Note that, in FIG. 1, a portion surrounded by a dotted line shows the discharge lamp fixture H, as in FIG. 4.

The operating state of the first embodiment will be described. Normally, the contact s ₁ is open and the contact s ₂ is closed. Here, a slow leak phenomenon occurs in the discharge lamp P, the current of the inductance element L ₁ increases, and as a result, the inductance element L ₁ abnormally generates heat and its temperature rises, the heat causes the recovery type thermal fuse SW ₁ to operate. The contact s ₁ is in a closed state, and therefore an exciting current flows through the exciting winding L ₂ of the relay switch SW ₂ , so that the contact s ₂ is opened and the discharge lamp P is de-energized. Then, after replacing the lamp tube of the discharge lamp P that caused the slow leak with a new lamp tube, the reset button (not shown) attached to the relay switch SW ₂ is manually operated to re-open the contact s ₂ . It makes a circuit.

FIG. 2 is an electric circuit diagram showing a second embodiment of the discharge lamp lighting device of the present invention. In FIG. 2, the same circuit components as those of the electric circuit diagram of FIG. 4 showing the conventional example are designated by the same reference numerals for description. Transformer T, full wave rectifier D, operational amplifier O and DC power supply V _cc This constitutes an overcurrent detection circuit as the first switching means. DC operation type relay switch SW as second switching means₃Contact point s₃ Is a normally closed type, and the inductance element L₁And contact s₃Receiving the input current from the power supply V via the secondary winding n of the transformer T₂The voltage generated at is full-wave rectified by the full-wave rectifier D, smoothed by the capacitor C, and then input to the non-inverting terminal (− side) of the operational amplifier O. When the input current exceeds a preset threshold value, each circuit constant in the electric circuit is determined so that the output terminal a of the operational amplifier O becomes "high" level.

At the same time that the output terminal a of the operational amplifier O becomes “high” level, the timer M is triggered and the output terminal b of the timer M converts from “low” level to “high” level. The timer M keeps the "high" level for a certain period of time (taken longer than the time required for the starting current to start flowing after the power is turned on and the current value becomes below the threshold value), and the time After that, the level becomes "low". An inverter I is connected to the next stage of the timer M to invert the output from the timer M. Then, the signals at the output end a of the operational amplifier O and the output end c of the inverter I are input to the AND circuit A.

In this way, the output end a of the operational amplifier O is set to the “high” level even though the output end b of the timer M is set to the “low” level. Means that an overcurrent continues to flow in the primary winding n ₁ of the AND circuit A. In this case, the output terminal d of the AND circuit A is at the “high” level, and in other cases, the AND circuit A 1 The output terminal d is at "low" level. Then, if the output terminal d of the AND circuit A is "high" level, since the excitation current to the excitation winding L ₃ of the relay switch SW ₃ is Ru flow, since the contact s ₃ interrupt the energization of open circuit to the discharge lamp P is there.

The contact s ₃ of the relay switch SW ₃ is a normally closed type, and when it is once opened, it has the function of being closed for the first time when a reset button (not shown) is manually pressed to operate. It has a DC operation type mechanism. In the above description of the second embodiment, FIG. 3 shows an output characteristic diagram of the output end a of the operational amplifier O, the output end b of the timer M, the output end c of the inverter I, and the output end d of the AND circuit A with respect to time t. ing.

[0015]

[Effect of device]

 This invention is constructed as described above and has the following effects. That is, the lamp current flowing in the discharge lamp that caused the slow leak is automatically cut off by the first switching means, the lamp tube of the discharge lamp is newly replaced, and then the second switching means is manually operated. For the first time, the discharge lamp current again flows into the lamp tube of the new discharge lamp to bring it into a normal lighting state, and it is possible to reduce the deterioration of circuit elements such as inductance elements and design the entire device in a compact size. Moreover, there is an advantage that an interlayer short circuit accident of the inductance element can be prevented.

[Brief description of drawings]

FIG. 1 is an electric circuit diagram showing a first embodiment of a discharge lamp lighting device of the present invention.

FIG. 2 is an electric circuit diagram showing a second embodiment of the discharge lamp lighting device of the present invention.

FIG. 3 is an output characteristic diagram of the output terminal of the operational amplifier, the output terminal of the timer, the output terminal of the inverter, and the output terminal of the AND circuit with respect to time in the electric circuit diagram of the second embodiment.

FIG. 4 is an electric circuit diagram showing an example of a conventional discharge lamp lighting device using a resettable thermal fuse.

[Explanation of symbols]

SW ₁ reset type thermal fuse (first switching means) L ₁ inductance element s ₁ contact SW ₂ relay switch (first switching means) L ₂ excitation winding s ₂ contact P discharge lamp

Claims (1)

[Scope of utility model registration request] 1. A discharge lamp lighting device comprising an AC power supply, an inductance element for limiting the current of the discharge lamp, and a discharge lamp, wherein it is detected that an overcurrent continuously flows into the discharge lamp for a certain period of time or more. And a first switching means for opening and closing the second switching means, which is opened by the opening or closing operation of the first switching means and is manually closed by the discharge lamp in series with the power supply. A discharge lamp lighting device characterized by being connected.