10 Problems that Can Cause Led Driver Failure (Part 3)
Mar. 24, 2020
5. The test results are different with different loads
Non waterproof LED driver with LED lamp test, it is normal, with electronic load test, the result is likely to be abnormal. Usually this happens for the following reasons:
(1) the output instantaneous voltage or power of the driver is beyond the working range of the electronic load meter. (especially in CV mode, the maximum test power should not exceed 70% of the maximum load power, otherwise the load may overpower during loading, resulting in the drive not working properly or loading.)
(2) the characteristics of the electronic load meter used are not suitable for measuring constant current source, and the load voltage tap position jumps, resulting in the driver not working normally or loading.
(3) because the input of the electronic load meter will have a large capacitor in it, the test is equivalent to connecting a large capacitor in the output of the driver, which may cause instability in the current sampling of the driver.
Because the LED driver is designed to meet the working characteristics of LED lamps, the closest to the actual and real application of the test method should be to use LED beads as load, ammeter and voltmeter series to test.
Non Waterproof Led Driver
6. Outdoor LED driver may be damaged due to the following common conditions:
· connect AC to the DC output of the drive, resulting in the failure of the drive;
· connect AC to input or output of DC/DC drive, resulting in drive failure;
· connect the constant current output end with the dimmer, resulting in the failure of the actuator;
· connect the phase line to the ground line, resulting in no output of the driver and live enclosure;
7. Wrong phase connection
Generally, outdoor engineering applications are three-phase four-wire system. Taking the national standard as an example, the rated working voltage between each phase line and the zero line is 220Vac, and the voltage between the phase line and the phase line is 380Vac. If the construction worker connects the driver input end to two phase lines, the product will fail due to excessive input voltage of LED driver after energizing.
Because of the difference in the input resistance, when one driver is charged to start, the internal resistance decreases and the voltage may be mostly applied to the other driver, resulting in its over-voltage damage and failure. Therefore, it is recommended that the same distribution branch, switch or circuit breaker to break together, can not only disconnect the zero line.Do not put distribution fuse on the zero line, the line to avoid the zero line bad contact.
8. The fluctuation range of the power grid exceeds a reasonable range
When the distribution line of the same transformer power grid branch is too long and there are large power equipment in the branch, when the large equipment starts and stops, the power grid voltage will fluctuate violently, even causing the power grid instability. When the instantaneous voltage of the grid exceeds 310Vac, it is possible to damage the driver (even with the lightning protection device is not effective, because the lightning protection device is to deal with a few tens of us-level pulse spikes, and the power grid fluctuations may reach tens of mS, or even hundreds of mS). Therefore, the street lighting branch power grid has a large power machinery to pay special attention to, it is best to monitor the fluctuation of the power grid, or a separate power transformer power supply.
9. The line trips frequently
Too many lights on the same road lead to overload of the load on one phase of the electricity and uneven power distribution between the phases, resulting in frequent trip lines.
10. Drive heat dissipation
When the actuator is installed in a non-ventilated environment, the actuator shell should be in contact with the lamp shell as far as possible. If conditions permit, the contact surface between the shell and the lamp shell should be coated with thermal adhesive or thermal pad to improve the heat dissipation performance of the actuator, so as to ensure the life and reliability of the actuator.
To sum up, there are many details of LED driver in practical application that need to be paid attention to, and many problems need to be analyzed and adjusted in advance to avoid unnecessary failure and loss!