JLS UL CLASS J FAST-ACTING FUSE 450A. JLS series fuses provide space-saving, fast-acting overload and short-circuit protection for non-inductive loads. When used for motors or other inductive loads, the ampere rating of JLS series fuses must be increased to prevent nuisance opening on inrush currents. In such applications, JLS fuses may provide only short circuit protection. Consider using Littelfuse POWR-PROÖ JTD series time-delay fuses in such circuits. Applications: General purpose circuits with little or no motor load. Resistive loads, such as resistance electric heat. Loads requiring fast-acting overload protection, such as equipment containing solid-state devices. Space Saving: JLS fuse characteristics are similar to KLNR/KLSR fast-acting Class RK1, but they are much smaller. Safety: 200,000 A.I.R. ù Reliable interruption of all overcurrents up to 200,000 amperes. Extremely current limiting ù Stops damaging short-circuit current faster than any mechanical protective device. Fast-Acting ù Provides fast-acting protection to equipment such as variable speed drives, rectifiers and other equipment containing surge-sensitive components. Longer Equipment Life: Current-limiting design reduces damage to equipment caused by heating and magnetic effects of short-circuit currents. Economical: Extremely current-limiting design often permits use of readily available, less costly equipment. Manufacturers of equipment containing dual voltage devices can simply manufacturing and reduce inventory by standardizing on 600 volt JLS fuses and Class J fuse blocks for all AC voltage ratings. Easy to Use: 200,000 A.I.R. rating minimizes need for short-circuit calculations.