SMD® Power Fuses - Outdoor Distribution IntelliTeam® SG Automatic Restoration System IntelliTeam® FMS Feeder Management System IntelliTeam® CNMS Communication Network Management System IntelliRupter® PulseCloser® Fault Interrupter IntelliCap® Automatic Capacitor Controls & Sensors

This broad selection of ampere ratings and speeds permits close fusing to achieve maximum protection and optimum coordination.SML Power Fuses, further, include Uni-Rupter®, which provides 200-ampere single-pole live switching of single-phase and three-phase circuits on distribution systems through 25 kV. They’re available in a wide variety of ampere ratings, in five different speeds: S&C “K”, Standard, Slow, Very Slow, and Coordinating. Vista® and Vista® SD Underground Distribution SwitchgearWith SM and SML Power Fuses, source-side devices may be set for faster operation than practical with other power fuses or circuit breakers, thereby providing better system protection without compromising coordination.SM and SML Power Fuses are offered with maximum continuous current ratings of 200, 300, 400, and 720 amperes, in a variety of fault-interrupting ratings.

Both main and auxiliary arcing rods are drawn upward by spring-and-cable assembly in the holder. The strain wire severs, initiating arcing. Overcurrent melts the silver fusible element. Here’s how it works.Fault Interruption of SM-4Z, SML-4Z, SM-5S, and SM-5SS Power Fuses: Since circuit interruption is internal to Uni-Rupter, there’s no external arc or flame.(On mobile, swipe left for remaining ratings information.) SM Power Fuses are available in the following ratings: Fuse TypeSML Power Fuses are available in the following ratings: Fuse TypeFast, positive fault interruption of SM Refill Units and SMU Fuse Units is achieved through high-speed elongation of the arc in the solid-material-lined bore, and by the efficient deionizing action of gases generated through thermal reaction of the solid material due to the heat of the confined arc.

Any arcing in the auxiliary bore can’t persist, and quickly transfers to main arcing rod in the main bore. For moderate-to-high-faults, auxiliary arcing rod — momentarily providing the only path for the fault current — quickly melts at reduced section and separates from the one-inch long arcing tip. For low-magnitude faults, arcing is reinitiated in small-diameter auxiliary bore when the tip of the auxiliary arcing rod travels about one inch (and clears auxiliary contact).

The fluorescent fire-orange target is visible in the “blown-fuse” indicator window of the holder.Fault Interruption of SM-20, SML-20, and SM-40 Power Fuses: For moderate-to-high faults, after main arcing rod has traveled about one-half stroke, sufficient deionization has occurred to extinguish the arc. For low-magnitude faults, after auxiliary arcing rod has traveled about one-half stroke, sufficient deionization has occurred to extinguish the arc. The large circumference of main bore provides greater surface exposure of the arc-extinguishing medium to the heating effects of the arc, thereby enhancing generation of arc-quenching deionizing gases. For moderate-to-high faults, arc is lengthened as main rod is drawn upward into the main bore.

Switchgear Fuses