Test method of LED power supply for bad situation
In the process of using LED switching power supply, users find that the power supply does not work properly, but the power supply is found to be good after returning it to the factory for testing. This situation usually occurs due to the following reasons.
1.Short-circuit protection of LED power supply. When the LED lamp short-circuit, the LED power supply will enter the short-circuit protection state, the LED lamp will not light.After the elimination of the short circuit, the power supply 220V input disconnected from the electricity, after an interval of 2 minutes to connect, LED power can resume work. LED light short circuit may be a short circuit on the engineering line, or it may be a short circuit inside the LED light. The former is easier to troubleshoot, the latter is more secretive, but the general multimeter test can be detected. Short circuits sometimes show an atypical state, for example, sometimes they will short circuit and sometimes they will not. Or if the waterproof insulation is not done well, it will short circuit when it rains, and will not short circuit when it dries (so there will be more short circuit protection when it rains). For example: when it rains the light has a short circuit, due to the power supply 220V input is not disconnected and restarted after 2 minutes, the power supply can be able to resume working state, the light can’t be bright. When the rain dries up, there is no short circuit, but replace a new LED power supply, the light is normally on, it will be mistaken that the original LED power supply is bad.
2.Overload protection of LED power supply. When the power of the LED lamp exceeds the normal output power of the LED power supply, the LED power supply will be in a state of protection, the LED lamp will appear flicker or dimmed brightness. Sometimes customers replace a LED power supply of the same, the load can be restored to normal. This is because the overload protection of the LED power supply is set to a range of values, can not do the same for each one. For example, 600W LED power supply, its protection value is between 605W-620W, if the LED lamp is 610W, then the protection value in the 605W power supply will protect, the protection value in the 620W power supply will not protect. It is worth noting that some LED lights with the working time consumed by the power will gradually increase, there will be no overload at the beginning, after a while there will be an overload situation.
3.Over-temperature protection of LED power supply. In order to prevent the LED power supply due to high temperature damage or fire combustion, LED power supply will be equipped with over-temperature protection device. When the LED power supply in the over-temperature protection state, the LED power supply will stop working, when the temperature drops, the power supply will resume working again.
4.LED power supply used for a long time, terminals and wire barge interface is prone to poor contact or oxidation, these may lead to power supply can not provide normal electricity to the load, thus causing the illusion of power damage.
5.Input voltage is too low. Power supply input voltage has a range value, such as 180~250V, when the voltage is lower than 180V, LED power supply can not work properly, LED lights will flicker or not bright.
6.The connection line between LED power supply and LED lights is too long, too thin, at this time if the LED power supply output is 12V24V, after the loss of the line to reach the LED lights may only be left 10V-20V. LED lights because they do not get enough voltage, there will flicker or not bright.
7.When the load is a capacitive load (such as LED lights with capacitors on the board), it may cause the LED power supply to fail to start normally and the lights will flicker. This is because the current required by such loads at the moment of power-on is much larger than the current required for normal operation as indicated, and even exceeds the maximum output power of the power supply, causing the power supply to fail to start normally. So this kind of load configuration power supply, the power of the selected LED power supply should leave enough margin (according to past experience, the power of the power supply should be more than 1.4 times for this kind of load).
8.The positive and negative polarity of LED power supply’s output and the positive and negative polarity of the light connected to the reverse, the light will not bright.
To sum up, to determine whether a power supply is damaged, we can not just look at the LED power supply with the load can work properly, the key or directly to test the LED power supply. The simpler way is to change the LED power supply to a different place to test whether it can work properly.