1 ® S&C Positrol Fuse Links DESIGN MAKES A DIFFERENCE. Eliminate unnecessary cutout operations and reduce maintenance and operation costs.
2 ® Fuse Links S&C Positrol Have you ever had a distribution-fuse cutout operate unnecessarily or for an unknown cause? affect your maintenance and operations costs. This, in turn, On today’s power distribution systems, fuse cutouts play an affects your fuse link costs, making a $5 fuse link in reality a essential role in system and equipment protection. However, a key determinant in any cutout’s ability to function properly $13 fuse link or even higher. is the fuse link. The low-current fault-interrupting capabilities The key to eliminating this impact is to remove the essential to a reliable fuse are provided not so much by unnecessary cutout operations by using reliable fuse links the cutout, but by the fuse link. A failure of the fuse link to that operate only when required. perform as intended can result in nuisance fuse operations Positrol Fuse Links are designed to provide reliable protection, (sneakouts), needless outages and miscoordination with and they operate only when a fault occurs within the cutout’s other devices. To a utility, that’s dollars and cents . . . and it’s zone of protection. With Positrol Fuse Links, you eliminate not limited merely to the cost of a replacement fuse link. unnecessary cutout operations and thereby reduce your Although use of other manufacturer’s fuse links may result in maintenance and operation costs. small savings up front, the expense of finding and replacing Learn more about why design makes a difference at fuse links that sneak out can cost many times the initial sandc.com/positrol. investment. The outages caused by unnecessary operations of cutouts (due to the use of marginally designed fuse links) 2
3 Construction A B C — Allows fuse links Silver Majority Fuse Element A to carry current close to the minimum melting time without any damage — Better design to handle Helically Coiled Element B mechanical tension and stresses to avoid damage to fuse element Creates a — Swaging (Solderless) Connection C secure connection between the fuse element and other components 3
4 Features The following features of S&C Positrol Fuse Links provide Superior Fault-Interrupting benefits unobtainable in any other make of fuse link: Performance Nondamageability The superior fault-interrupting performance of S&C Positrol Fuse Links—particularly with respect to low-current S&C Standard Speed, S&C “K” Speed, and S&C “T” Speed transformer secondary-side faults—has been conclusively Positrol Fuse Links rated 6 amperes through 100 amperes demonstrated in extensive testing performed by S&C with and S&C “QR” Speed and S&C “N” Speed Positrol Fuse Positrol Fuse Links installed in S&C Type XS Fuse Cutouts as Links rated 10 amperes through 100 amperes use nickel- well as cutouts of other manufacturers. In all of these tests, S&C chrome or helically coiled silver or silver-copper eutectic Positrol Fuse Links provided superior performance across the fuse elements that are not affected by mechanical shock full range of secondary-fault current levels and under realistic or vibration or by transient surges that may heat the transient-recovery-voltage conditions. The outstanding element nearly to the severing point. Consequently, these fault-interrupting performance of S&C Positrol Fuse Links is fuse links are nondamageable—eliminating nuisance fuse attributable to the fuse-link sheath and, with respect to low- operations and providing the permanently accurate time- current transformer secondary-side faults typically handled current characteristics essential to the integrity of carefully by fuse links rated 50 amperes and below, attributable to a engineered system coordination plans. Also, because S&C special high-strength extruded thermo-plastic sheath. The Positrol Fuse Links are nondamageable, there is no need extruded thermo-plastic sheath is essential in the lower- to replace companion Positrol Fuse Links on suspicion of ampere-rated fuse links because low-current transformer damage following an adjacent-fuse operation. secondary-side faults are not only the most difficult to clear, but also the most frequently experienced. S&C Universal- Close Tolerance Style Positrol Fuse Links provide unsurpassed secondary- fault performance for applications 14.4 kV through 24.9 kV S&C Positrol Fuse Links incorporating silver or silver-copper and to single-phase-to-neutral applications through 38 kV. eutectic fusible elements have a total melting current tolerance of 10% within the coordinating range (i.e., melting times less than 10 seconds) compared to the 20% tolerance for tin-element fuse links. The close tolerance is possible because of physical properties inherent to silver and silver- copper eutectic fuse-element materials and because of the meticulous care exercised in the manufacture, handling, and assembly of S&C Positrol Fuse Links. (S&C inspects fuse-element wire using a sophisticated laser micrometer to ensure diametral tolerances as small as 0.0002 inches.) The narrow tolerance band for precision-manufactured S&C Positrol Fuse Links not only permits closer fusing for improved protection, but also more precise series coordination of fuse links with other fuse links or with reclosers for enhanced service reliability. 4
5 Options S&C Positrol Fuse Links are available in Universal, Indicating, and Open styles. Typical construction features for the Universal style are illustrated here. For a complete listing of fuse-link styles, speeds, ampere ratings, and catalog numbers, refer to the Ratings table on page 6. Corona shield 5 Fuse element (nickel chrome) Figure 1. S&C Standard Speed Fuse Links rated less than 6 amperes; S&C “QR” Speed and S&C “N” Speed Fuse Links rated less than amperes. 10 Fuse element (silver or silver-copper eutectic) —helically coiled to absorb mechanical vibration and thermal shock (typical) 50K Strain wire —restrains static force of flipper spring (typical) Figure 2. S&C Standard Speed, S&C “K” Speed, and S&C “T” Speed Fuse Links rated 6 amperes through 100 amperes; S&C “QR” Speed, and S&C “N” Speed Fuse Links rated 10 amperes through 100 amperes. Fuse element (silver-tin, cast-tin, or silver-copper eutectic) 140K Figure 3. S&C Standard Speed, S&C “K” Speed, S&C “T” Speed, S&C “QR” Speed, S&C “N” Speed, and S&C Coordinating Speed Fuse Links rated greater than 100 amperes. 5
6 Ratings Style Speed Rating, Amperes Catalog Number ① 64xxxR1 1 through 100 S&C Standard 64xxxR1 125 through 200 ■ 265xxxR1 6K through 100K ● S&C “K” Universal ■ 265xxxR1 140K and 200K Usable in Positect Not ( Cutout) ™ S&C “T” 6T through 200T ● ■ 279xxx R1 338xxxR1 1QR through 100QR 23-Inch (584-mm) S&C “QR” ② ■ 125QR through 200QR 355xxx R1 Overall Length 5N through 200N S&C “N” ③ 267xxxR4 ■ 101 through 103 S&C Coordinating 179xxxR1 ▲ Universal ™ Cutout) (Usable in Positect 1 through 100 364xxx S&C Standard 23-Inch (584-mm) Overall Length Indicating (Usable in Positect Cutout Only) ™ 3 through 100 115xxx S&C Standard 10-Inch (254-mm) Overall Length Open 1 through 25 774xxx S&C Standard 8-Inch (203-mm) Overall Length ① - The ampere rating of the fuse link is represented in the catalog num These fuse links are interchangeable (with respect to time-current ③ characteristics) with discontinued GE Models 9F1C and 9F51AAN series ber by “xxx” (e.g., 1-ampere Standard Speed, Universal Style = 64001; fuse links. 25-ampere Standard Speed, Universal Style = 64025; 100-ampere Standard Speed, Universal Style = 64100). The 1-, 2-, and 3-ampere S&C Standard Speed Positrol Fuse Links ● These fuse links are interchangeable mechanically—and with respect ② meet requirements for coordination with fuse links rated 6K and 6T to time-current characteristics—with Kearney Type “QA” fuse links. For amperes as specified in IEEE Standard C37.42, and are recommended optional cable adapters for use with S&C “QR” Speed Fuse Links, add for use in “K” and “T” Speed fuse-link coordination schemes. suffix “-U” to the catalog number of the link. This adaptation of the fuse Fuse links rated 125-200 Std., 140K, 200K, 140T, 200T, ■ link is for use with cutouts having bolt-type connections for upper as well 125QR-200QR, and 125N-200N are for use in 200-ampere cutouts. as lower fuse-link cables. Overall length of all “QR” Speed Positrol Fuse For use in 100-ampere cutouts. ▲ Links equipped with suffix “-U” cable adapter is 26 inches (660 mm). 352-30 December 3, 2018 6 © S&C Electric Company 1964-2019, all rights reserved • sandc.com
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