If you want to use the emergency fire lighting for a long time, you should maintain it on time in the daily use process, and learn to eliminate the failure of the lighting. Today, we will introduce the common failure causes and treatment methods of the emergency fire lighting.
1. The main power supply is normal, but the indicator is not on.
The fault is mainly caused by the damage of LED. It can be welded. You can use a multimeter to judge whether it is in good condition. The greater the current limiting resistance R1 or the open circuit resistance, the less bright it will be.
2. When the power supply is cut off, the indicator light is still on.
The fault is caused by deterioration or breakdown of the reverse characteristic. The fault can be eliminated by replacing an IN4004 rectifier diode.
3. After the power is cut off, the brightness of the lamp will decline after a period of normal operation.
This indicates that the battery may be faulty. Because there are no protective measures for the circuit to prevent battery load, if the power supply is cut off for a long time, the battery cannot be disconnected. When the terminal voltage of the battery discharges 10v, the battery will discharge and its pole plate will be damaged prematurely. A better solution to battery over discharge is to establish a protection circuit. The circuit is relatively simple. In the process of emergency lighting, when the terminal voltage of the battery is lower than 10V, VD will be cut off, relay KA will be released, and the load circuit of the battery will be cut off to avoid over discharge and shorten the service life of the battery. KA can select domestic JRX-13F high sensitivity relay, with pull in current of 8mA and pull in voltage of 6V. The voltage stabilizing value of the voltage stabilizing diode is 5V.
4. Emergency lighting lamp circuit failure
Switch function SA2 emergency lamp circuit: when SA1 is off, SA2 is placed at the "start" position, L1T2 of voltage oscillation transformer on winding is applied to one end of filament tube of lamp through SA2 and ground power supply (battery), and L3 of voltage on winding is applied to the other end of filament tube. After preheating for about 3 seconds, turn switch SA2 to the "ON" position. At this time, the high-frequency pulse voltage induced on L2 winding acts on both ends of the lamp, and the lamp turns on.
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