Led Lighting Spd Design Installation Guide Page 14 LED Lighting SPD Design & Installation Guide

LED Lighting Surge Protection Modules Design and Installation Guide 2015 Littelfuse LED Lighting SPD Module Design and Installation Guide www.littelfuse.com End-of-Life/Replacement Indication for SPDs When an MOV becomes overheated due to temporary over-voltage or excessive leakage current, a thermal disconnect may be used to help remove it from the AC circuit. However, with the MOV removed from the circuit, the SPD module no longer provides surge suppression. Therefore, it's important to supply proper indication so that maintenance personnel will know the SPD is not working and requires replacement. Luminaire designers can choose from two main types of SPD module configurations based on their maintenance and warranty strategies. Those are parallel- and series-connected surge protection subassemblies. Parallel Connection - The SPD module is connected in parallel with the load. An SPD module that has reached end-of-life is disconnected from the power source while leaving the AC/DC power supply unit energized. The lighting still remains operational, but the protection against the next surge to which the power supply unit and LED module are exposed is lost. In a parallel-connected SPD module, replacement indication can be added through the use of a small LED that indicates the SPD module status to the maintenance technician. Options for a green LED indicating an online SPD module or a red LED indicating an offline SPD module are available. Or, rather than an LED indication at each lighting fixture, the need for SPD module replacement could be indicated remotely to a light management center with SPD module end-of-life indication wires connected to a networked smart lighting system. Series Connection - The SPD module is connected in series with the load, where the end-of-life SPD module is disconnected from the power source, which turns the light off. The loss of power to the luminaire serves as indication for a maintenance call. The disconnected SPD module not only turns the lighting off to indicate the need for replacement but also isolates the AC/DC power supply unit from future surge strikes. General preference for this configuration is growing rapidly because the luminaire investment remains protected while the SPD module is awaiting replacement. It's far less expensive to replace a series-connected SPD module than the whole luminaire as in the case of a parallel-connected SPD module. Figure 14. An SPD module that's parallel-connected to a luminaire (a) and an SPD module that's series-connected to a luminaire (b). (a) (b) Over-voltage Testing in UL 1449 and IEC 61643-11 (continued) 14

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