DC overcurrent protection-where we stand

Most DC systems require some form of overcurrent and/or short circuit protection. As with any fuse selection, the three elements of system voltage, normal load current, and available short-circuit must be considered. For proper application, the fuse's ratings must equal or exceed the system parameters. Manufacturer's published data are usually based on AC ratings, and the burden often falls on the user to determine the DC applicability. Furthermore, the manufacturer's DC test data may not necessarily apply to the DC system at hand. Factors including circuit time constant, voltage, and available short-circuit current may preclude the use of certain DC rated fuses. The procedures used to determine the DC ratings for fuses are addressed. The issues pertinent to insuring a proper DC fuse application are discussed.<
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