Trouble maintenance of emergency lights for fire-fighting equipment

Failure maintenance of emergency lights for fire-fighting equipment. Fire-fighting equipment emergency lights can solve the problem of temporary power outages. Therefore, many households in urban and rural areas have fire-fighting equipment emergency lights to prepare for power outages. Of course, due to various reasons, emergency lights for fire-fighting equipment will inevitably fail during use. This article takes a 11W domestic fire-fighting equipment emergency light as an example to analyze common failures and maintenance methods of fire-fighting equipment emergency lights for reference.

  malfunction repair

　　 1. The emergency light of fire fighting equipment does not light up after turning on switch SA1

　　 Disconnect SA1, use a multimeter at DC 1A gear (if this gear is not available, 500mA gear can also be used for speed measurement) and at both ends of SA1, the current should be about 500-V 600mA under normal conditions. Note that the switch SA2 should be in the "lit" position at this time. If the current is normal, it means that SA1 is damaged and needs to be replaced: if there is no current, check the windings L4 and L5 of T2. Use a multimeter to measure the ohm range to determine: Finally, weld the VT to test whether the performance is good. When you need to replace it, you can use the β value in Medium power tube above 120. If there is still no current, use a multimeter to check whether the resistances R2 and R3 are changed or open, and whether VD7. C2 is short-circuited. After the above-mentioned overhaul and treatment, turn on the switch SA1, and the lamp tube should be able to light up normally.

　　 2. The mains power supply is normal but the indicator light is off

　　 This failure is mostly caused by the damage of the light-emitting diode. You can solder the VD5 and use a multimeter to judge whether it is in good condition. The resistance value of current limiting resistor R1 becomes larger or open circuit will also cause VD5 to not light up.

　　 3. When the mains power fails, the indicator light is still on

　　 The failure is caused by the deterioration or breakdown of the reverse characteristics of VD6. Just replace an IN4004 rectifier diode, the fault can be eliminated.

　　4. After the power failure, the brightness of the lamp will decrease immediately after normal operation

　　 This indicates that the battery may be faulty. Because this circuit has no protective measures to prevent battery over-discharge, if the mains power outage is too long and the battery is over-discharged to a terminal voltage of 10V, failing to disconnect SA1 will cause the battery to over-discharge and cause its plate to be damaged prematurely.