KLSR series RK1 fuses were the earliest type of current-limiting fuse developed. Their single-element, silver link design enables them to provide fast-acting overload and short-circuit protection. When used to protect inductive loads such as motors, solenoids, and transformers, KLSR series fuses must be greatly oversized to prevent opening the fuses on harmless inrush currents. In such applications, KLSR series fuses may only provide short-circuit protection. We recommend using POWR-PRO™ LLNRK/LLSRK series RK1, dual-element, time-delay fuses in all new applications requiring the current-limiting ability of UL Class RK1 fuses, or in existing applications where fast-acting RK1 or RK5 fuses have been opening on harmless system surges such as motor starting currents.Safety: 200,000 A.I.R. — Reliable interruption of all overcurrents up to 200,000 amperes. Extremely current limiting — Stops damaging short-circuit current faster than any mechanical protective device. Fast-acting — 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 — often permits use of readily available, less costly equipment. Used as input or output fuses for surge-sensitive components, such as variable speed drives and rectifiers, fast acting KLNR/KLSR fuses may prevent opening of expensive semiconductor fuses protecting individual components. Easy to Use: 200,000 A.I.R. rating minimizes need for short circuit calculations. Dimensions: Refer to FLNR for KLNR dimensions and FLSR for KLSR dimensions.