JPS5936395B2 - emergency lighting circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an emergency lighting circuit, and its purpose is to provide an emergency lighting circuit that can maintain a constant total luminous flux even if an unlit discharge lamp occurs during emergency lighting. There is a lighting circuit to obtain.

Conventionally, in the case of an emergency lighting circuit as shown in FIG. 5, in normal times when AC power supply 3 is supplied, a plurality of discharge lamps 1a and Ib, for example, two discharge lamps 1a and Ib, are respectively provided in the AC lighting circuit. Connect to the ballasts Ba and 8b and light them in parallel.

Also, when a power outage occurs, the relay 4 is de-energized, contacts 5, 6, and T of the relay 4 are connected from the No side to the NC side, and the battery 9 to be charged, which is connected to the charging circuit A, is connected to the inverter circuit 2. At the same time, the discharge lamps 1a and Ib are connected in parallel to the secondary output winding of the output transformer 10 of the inverter circuit 2 via a ballast capacitor C1C2, so that the discharge lamps 1a and Ib are turned on in an emergency. However, in the case of such a conventional example, when one of the discharge lamps 1a and Ib becomes emissive or defective, the luminous flux during emergency lighting becomes 1/2 of the luminous flux when both lamps are turned on, and the brightness necessary in an emergency is not achieved. The problem was that the emergency lighting circuit could not function properly. In the figure, 11 is an inverter transistor, 12 is a glow tube, 13 is a charging transformer,
14 is a current limiting resistor, and D is a rectifier diode. The present invention has been provided in view of the above-mentioned drawbacks, and will be described in detail below with reference to one embodiment. FIGS. 1 and 2 are circuit diagrams of one embodiment, and show the relay 4 in the conventional circuit described above.
A series circuit of a capacitor Cs and a contact 16 of the reed switch 15 is inserted in parallel between the contacts 6 and T of the NC, and the reed switch 15 is connected to the glow tube 1 of the discharge lamp Ib.
One end of the filament to be connected to 2 and the inverter circuit 2
The output transformer 10 is inserted in series with one end of the secondary winding of the output transformer 10. Note that the capacitances of the capacitors C1C2 are set to equal values. In the normal case when the AC power supply 3 is supplied, the discharge lamps 1a and Ib are lit for commercial use by the ballasts Ba and 8b of the AC lighting circuit, as in the above-mentioned conventional example.

Next, when a power outage occurs and the discharge lamps 1a and Ib are connected to the inverter circuit 2, and at least one of the discharge lamps 1a and Ib lights up, the coil of the reed switch 15 is excited by the current supplied from the inverter circuit 2. Contact 16
becomes closed. If both discharge lamps 1a and Ib are lit normally when this is closed, capacitor Cs and contact 16
Since the potential difference between both ends of the series circuit is zero, no current flows through the series circuit, and the output voltage of the secondary side of the inverter circuit 2 is applied to each of the discharge lamps 1a and Ib, and the capacitor ClC2 The lamp current determined by will flow. Now, if one of the discharge lamps 1a and Ib, for example, the discharge lamp 1a
If it does not light up due to a defect, capacitor C3 and contact 1
A potential difference is generated between both ends of the series circuit with 6, and non-lighting is detected, and current flows through the series circuit.

Therefore, the ballast controller for the discharge lamp Ib. , death,
The capacity of U3 anosa is +C2.

At this time, from C, +C, C, = C2,! 2. ”: If the capacitance of capacitor C3 is set so that +C2 = 2C2, the ballast reactance will be halved and the lamp current flowing through discharge lamp Ib will be doubled, and the luminous flux, which is approximately proportional to the lamp current, will be 2. It will be doubled.

That is, even though the discharge lamps 1a are not lit, the luminous flux is maintained equal to the luminous flux when all the lamps are lit. FIGS. 3 and 4 show another embodiment of the present invention, in which inductances are wound around the same iron core, are wound with opposite polarities, and have the same absolute value of inductance. IT and l8 are respectively connected to the contact 6 and T(7) NC side of the relay 4 and the capacitor C in the conventional circuit described above.
, C2 are inserted in series.

Therefore, when both the discharge lamps 1a and 1b are normally lit during emergency lighting, the inductive components of the inductances 17 and 18 are mutually canceled, and the inductive components of the discharge lamps 1a and Ib are determined by the ballast capacitors C and C2. The lamp current flows. At this time, for example, if the discharge lamp 1a is not lit due to a defect, current will no longer flow through the discharge lamp 1a, and the inductance 18 will have an inductive component. Therefore, a lamp current limited by the capacitor C2 and the inductance 18 flows through the discharge lamp Ib. Here, let the value of inductance 18 or IT be L, and ωL =
- If Jbρ is set, the lamp current flowing through the discharge lamp Ib will be twice that of normal lighting, and the luminous flux will be reduced to The luminous flux will be maintained at the same level.

Since the present invention is configured as described above, even if one of the discharge lamps is not lit, the lamp current of the normal discharge lamp is automatically increased to maintain the luminous flux equal to that when all the lamps are lit. It has the effect of being able to perform its functions to its full potential in an emergency.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of one embodiment of the present invention, Fig. 2 is a circuit diagram of the main parts of the above, Fig. 3 is a circuit diagram of another embodiment of the invention, and Fig. 4 is a circuit diagram of the main parts of the same. FIG. 5 is a circuit diagram of a conventional example, and 1a and Ib are discharge lamps.

Claims (1)

[Claims] 1. A plurality of discharge lamps, an emergency lighting means for energizing the discharge lamps in an emergency, a malfunction detection means for detecting and outputting a malfunction state of the discharge lamp in an emergency, and an output of the malfunction detection means. An emergency lighting circuit comprising lamp current increasing means for increasing the lamp current of the discharge lamp so that the total luminous flux of the normally lit discharge lamp is approximately equal to the total luminous flux when all the lamps are lit.