Sign & Digital Graphics

November '17

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22 • November 2017 • S I G N & D I G I T A L G R A P H I C S ELECTRIC SIGNAGE Fixed length strips may simply be rated in watts." Redmer, whose company supplies a range of LED products from multiple manufacturers, reminds sign shops that manufacturers are a great source for inquiries about LED projects. He says, "Manufacturers package LEDs by the bag and one power supply can power a bag. Nowadays, LEDs are being used for florescent replacement and are being put together in products like Principal LED's Quick Stick, which is basically LEDs put on a bar. You have to know how many feet you can run on one power supply; you should know the specs for the LED that you're putting in the sign and follow the manufacturer's recommendation." Finally, there are testing procedures that will help to determine if the power supply is appropriate for the sign. "Once the LEDs are wired in place and the correct input voltage is confirmed, the power supply should be wired to the LEDs and test lit," says Vincent. "Check the output voltage with a meter to make sure the LEDs are receiving the correct input from the output of the driver." The main point with getting an ade- quate test result is to ensure that the LED is not over- or under-powered. "Driving 12 VDC LEDs at slightly less than 12 VDC will result in a minimal loss in output, but driving them over 12 VDC can lead to overheating and loss of life," says Harrison. "Over voltage can come for high line voltage, or use of an exces- sively oversized driver." Life and Location One certainty of an LED driver unit is that its lifespan is uncertain. The ambi- guity of how long it may last is always in question. That does not mean you should expect a short life from the driver—these were built to last along with the LEDs. "If the LED company is offering a five-year warranty on the LEDs," Vincent notes, "you should demand a driver whose warranty is in lock-step with the LEDs as a system." He adds that many drivers can last somewhere in the 10-year range if oper- ated properly, however there are many more factors that can contribute to a driver's malfunction before the actual LED. "The driver is 100 times more likely to fail than the LED," Vincent continues, "so I recommend using LED drivers that have at least a five-year product and labor warranty that matches the LEDs being provided." Other factors may contribute to the life of an LED driver. Some are envi- ronmental, as noted previously, others are factors of the sign and components themselves. "The lifetime of a driver depends on a number of parameters," says Vincent. "Quality of components such as the FETs, capacitors, and other active and passive components inside; thermal characteris- tics of the unit and its ability if the driver to dissipate heat; and the load (the lower load on the unit, the longer it will last)." But when the necessary pre-plan- ning, attention to installation, and test- ing have been done, an LED sign can be a cost-effective, long-lasting solution for users. SDG In this job the power supply and RGB repeaters were incorrectly mounted directly side by side. According to Meyne, this caused a failure within 30 days of installation because the repeaters inadvertently became heat sinks, which they are not designed for. (Image courtesy of Bitro Group)

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