How to test the quality of LED drivers
How do we judge the quality of a drive after buying it? The following methods can help us test the LED driver's performance, safety, and protection mechanism.
1. Appearance judgment
Looking at the new LED driver we just received, we can check whether there are any gaps in the appearance and whether the workmanship is rough. If possible, we can burn it with fire without damaging its appearance to see if it is a safe flame-retardant plastic casing.
Wiring inspection: When there is no sign of any appearance, we check that the terminals and connecting wires are not loose, broken or fallen off.
2. Power on test
Without equipment:
Connection test: Find an LED light that meets the rated output of the driver and connect it to the output end of the driver. Ensure the wiring is correct (the positive and negative poles cannot be reversed) and then turn on the power and observe whether the LED lights up normally. If the light is on and stable, the driver is capable of providing basic current output.
With equipment:
Use an adjustable power supply to input different voltage values, from the lowest rated voltage to the highest rated voltage, and observe the startup and stability of the driver. Ensure that the driver should maintain stable output over the entire input voltage range without transitions or power outages.
Output current and voltage testing
Under different load conditions, measure whether the output voltage (constant voltage driver) or current (constant current driver) is stable and within the allowable error range of the nominal value. If the output current or voltage should comply with the driver's nominal value, the fluctuation range should be kept within ±5%.
3. Temperature test
Run the driver in a sealed space for a period of time, use a thermocouple or infrared thermometer to monitor its temperature rise, and check whether it is within the rated temperature range. The temperature should not exceed the manufacturer's recommended maximum temperature and the case temperature remains within a safe range.
If you don't have a thermometer, you can gently touch the surface of the drive to feel its temperature. If the temperature is moderate and not hot, the heat dissipation is good; but if the temperature is too high, there may be a heat dissipation or circuit problem. (Do not touch the overheated drive for a long time to avoid burns).
4. Dimming performance test
If the driver supports dimming function, you can connect the driver to a compatible dimmer to verify whether the driver's dimming function (0-10V, PWM, TRIAC, DALI, etc.) is normal. Test the driver's output stability and response speed under different dimming signal inputs, and observe whether the brightness of the LED light changes smoothly. If the brightness is too sudden or cannot be adjusted to the minimum brightness, the dimming performance of the driver may be poor.
If there are multiple dimming settings, you can test the smoothness of the brightness change step by step to ensure that there are no obvious gaps in the dimming process.
The normal dimming process should be smooth and flicker-free, and should not produce stroboscopic or intermittent phenomena under low brightness conditions.
5. Stroboscopic detection
Simple strobe detection can use the mobile phone camera to detect strobe. Turn on your phone's camera and get close to the LED light to observe the lighting on the screen. If you see obvious flickering or ripples, the driver may have a flickering problem; on the contrary, if the light is stable without ripples, the driver output is relatively stable.
Turn down the light intensity by visual inspection (if the dimming function is available), and visually inspect the light at low brightness. If flickering is detectable, the drive may not be suitable for flicker-sensitive locations.
Use a flicker tester to detect the flicker of the light source output by the driver at different brightnesses, especially the flicker performance at low brightness and dimming. Ideally, the driver output should be "flicker-free" or have a very low flicker index to ensure lighting comfort and quality.
6. Power factor test
To determine the power utilization of the drive and ensure that it meets the power factor (PF) standard, we can use a power factor meter to measure the power factor of the drive. Different regions have specific requirements for the power factor of LED drivers (such as above 0.9), especially in commercial applications. If the power factor of the drive meets the standard requirements, the reactive power consumption in the power grid can be reduced.
7. Protection test
Purpose: To ensure that the driver's protection function is activated under abnormal conditions to prevent damage to the driver and LED lamps.
step:
Overvoltage test: You can increase the input voltage appropriately to check whether the driver can automatically protect.
Overcurrent test: Increase the load current at the load end to see if the built-in protection of the driver is triggered.
Short circuit test: Instantaneously short-circuit the output terminal to observe whether the protection mechanism will be triggered and normal operation will resume.
If under the test conditions of overvoltage, overcurrent and short circuit, the driver should be able to automatically cut off power to protect the lamp, and can still resume work after the fault is eliminated, it means that the driver's built-in protection meets the standards and is of good quality.
8. Load testing
Try connecting LED lamps with different powers to the driver (but do not exceed the rated load of the driver) and observe the lighting conditions and brightness stability of the lamps. If the LED light can still work normally and stably after replacing the load, it means that the load capacity of the driver is good.
Use multiple LED lamps in parallel to observe whether the brightness of the lamps is consistent. If there is an obvious brightness difference, it may be that the driver's output current is not stable enough.
9. Durability test
When near full load, run the drive continuously for several to dozens of hours to observe whether it works stably and whether there is overheating, flickering, frequent extinguishing, etc. This tests the drive's stability and reliability after long-term use. If the drive can still remain stable after a long period of continuous operation, and the temperature changes remain within a reasonable range, and there are no abnormal fluctuations or damage, it means that the drive is of high quality.
Through the above tests, we can comprehensively judge the overall performance and safety of the LED driver.
