Sign & Digital Graphics

November '18

Issue link: https://nbm.uberflip.com/i/1041011

Contents of this Issue

Navigation

Page 21 of 72

S I G N & D I G I T A L G R A P H I C S • November 2018 • 17 "A sign maker can buy an IP68 power supply that has built-in features that make it weatherproof," says Bluhm. "Otherwise they can use a UL-approved power supply box and install the units inside." However, Blevons warns that if some type of enclosure is used, sign makers should be cautious. "You must keep in mind that the heat generated by the driver internally must be dissipated as I have seen poorly designed fixtures that do not provide a means of removing this heat and will greatly reduce the life of the driver," he says. Overcoming Failure Finally, we can talk about what to do in case of emergency. How do you over- come obstacles? What should you do to improve the performance of your driver and LED sign? When do you know it's time to make replacements? There are a number of precautions to take including, "Testing the primary and secondary wires with a volt meter for output is the most common method for trouble shooting power supplies," offers Bluhm. In a similar fashion, Hovey points to the input voltage indicator that is present on The France Atlas Power Series. "It will be green when everything is work- ing and red if it is overloaded," he says. "If it is flashing, there is a serious prob- lem in the LED string. With the power turned off, disconnect the LEDs from the power supply. Turn the power back on and check the indicator again. If it is green, there is a problem with the LED string. If it is still flashing or red, then the power supply has an internal problem." When using products that have no indicators, sign makers can still evaluate the configuration for problems. "If there is no indicator, find the last L E D module in the string and mea- sure the DC voltage after that module," instructs Hovey. "It should be above 10 VDC. If it is lower, turn the power off and disconnect the LEDs from the power supply. Turn the power back on and mea- sure the output of the power supply. If it is 12 VDC there is a problem with the LED module string. If it is less than 10 VDC at the power supply, then it should be changed." At some point, users will recognize when it is time to replace the driver—in the case of failure or an unforeseen prob- lem. But in many instances, the LEDs may give out first. "If routine maintenance is planned, drivers are sometimes replaced if they are near the end of their expected life," says Blevons, "otherwise if a fixture is not operating properly it just needs to be determined if the issue is due to failure of the LEDs or the driver, which is usually done by installing a new driver tempo- rarily and confirming correct operation right away." Unexpected Failures There may also be instances when users simply do not know what problems are occurring. Blevons says that, "if you are having unexpected failures you will want to monitor the case temperature in the application and the input voltage to ensure they are within the expected ranges as those are the two most com- mon failure modes." However, if the correct drivers are chosen—those that can withstand the elements and handle the LED output— most problems can be sidestepped. When drivers are functioning properly, they are running LED signs efficiently and effec- tively. And these are drivers that get the most mileage out of each sign. SDG SOLID OBJECT MOISTURE 1 Protected against a solid object greater than 50mm, such as a hand. 1 Protected against vertical falling drops of water. Limited ingress permitted. 2 Protected against a solid object greater than 12.5mm, such as a finger. 2 Protected against vertical falling drops of water with enclosure tilted up to 15 degrees from the vertical. Limited ingress permitted. 3 Protected against a solid object greater than 2.5mm, such as a screwdriver. 3 Protected against sprays of water up to 60 degrees from the vertical. Limited ingress permitted. 4 Protected against a solid object greater than 1mm, such as a wire. 4 Protected against water splashes from all directions. Limited ingress permitted. 5 Dust protected. Limited ingress of dust permitted. Will not interfere with operation of the equipment. 5 Protected against jets of water. Limited ingress permitted. 6 Dust tight. No ingress of dust. 6 Protected against powerful jets of water. Limited ingress permitted. 7 Watertight against the effects of immersion in water between 15cm and 1m for 30 minutes. 8 Watertight against the effects of immersion in water under pressure for long periods. IP65 Ingress Protection IP (ingress protection) ratings help users determine which type of power supply will work in which application. (Image courtesy of SloanLED)

Articles in this issue

view archives of Sign & Digital Graphics - November '18