Low Voltage Fuses BLC, CR and CS types Super Rapid Fuses BLC, CR and CS types Super Rapid Fuses 150-1500 Volts AC 10-4700 Amps Description The FUJI BLC, CR and CS types are extremely reliable fuses which have been specially developed to provide protection for silicon diodes and thyristors and are suitable for inverters using semiconductors or transformersrectifiers. FUJI Super Rapid Fuses are designed with a very small total I 2 t value which gives them a high speed interrupting action in the face of abnormal currents. In addition the arc voltage generated at the time of interruption has a low value so that faults will not influence related electric machinery and equipment. These fuses can carry out the protection of many types of circuits rating from the semiconductor overcurrents to destructive shortcircuiting faults-i.e. when the SD-36 BLC SM-388 CR2L SI-431 CS5F semiconductors short or circuits fail the sound elements will be quickly isolated from the fault circuits. Features * The total clearing I 2t is small and the semiconductor circuit is completely protected. * Since the peak arc voltage at the time of interruption is low damage to other equipment does not occur. SI-429 CS10F * High interrupting capacity of 200kA at 1000V AC * The CS type is provided with a blown fuse indicator. An alarm contact block (1NO or 1NC) can also be attached. UL recognized: CR2L/UL,CR2LS/UL, CR6L/UL (File No. E92312) CSA certificated: CR2LS/UL (File No. LO4000-4090) TUV: CR2LS/UL (10-100A), CR2L/UL (150-350A) (Rep. No. E9450643E02) CR6L/UL (50-300A) (Rep. No. E9560543E02) Specifications Rated current (A) 12 20 23 45 75 90 120 140 30 50 75 100 125 140 150 175 200 225 260 300 325 350 400 450 500 550 600 Rated Peak voltage arc voltage (V) 550V 1550 AC 1550 1550 1380 1250 1250 1200 1200 250V Max. AC 500 Max. interrupting I2t Watt loss Fuse-link Rated current (Amp xsec.) 2 x 103 0.09 0.27 0.39 1.8 5 11.5 33 100 0.35 0.85 2.3 4.0 6.5 7.0 9.5 13 17 22 27 38 49 60 103 140 160 200 215 Type (W) 5.1 8.5 10 19 32 38 51 59 4.0 6.0 9.0 12.0 14.0 16.0 18.0 21.0 23.0 26.0 30.0 35.0 37.0 37.0 39.0 46.0 48.0 51.0 56.0 BLC012-1 BLC020-1 BLC023-1 BLC045-1 BLC075-1 BLC090-1 BLC120-1 BLC140-1 CR2L-30 CR2L-50 CR2L-75 CR2L-100 CR2L-125 CR2L-140 CR2L-150 CR2L-175 CR2L-200 CR2L-225 CR2L-260 CR2L-300 CR2L-325 CR2L-350 CR2L-400 CR2L-450 CR2L-500 CR2L-550 CR2L-600 (A) 10 20 30 50 75 100 20 30 50 75 100 Rated Peak Max. voltage arc interrupting I2t voltage (Amp2xsec.) x 103 (V) 250V Max. 0.04 AC 500 0.17 0.35 0.85 2.3 4.0 600V Max. 0.14 AC 1200 0.35 1.8 3.0 7.0 150 200 250 300 350 400 500 600 18 30 70 95 150 200 390 700 Watt loss Fuse-link Type (W) 1.2 3.0 4.0 6.0 9.0 12.0 4.0 7.0 9.0 12.5 15 CR2LS-10 CR2LS-20 CR2LS-30 CR2LS-50 CR2LS-75 CR2LS-100 CR6L-20 CR6L-30 CR6L-50 CR6L-75 CR6L-100 22.0 34.0 37.0 40.0 45.0 55 60 70 CR6L-150 CR6L-200 CR6L-250 CR6L-300 CR6L-350 CR6L-400 CR6L-500 CR6L-600 08 Interrupting capacity CR2LS . 100kA at 250V AC CR6L .... 100kA at 600V AC Interrupting capacity BLC ...... 100kA at 550V AC CR2L .... 100kA at 250V AC Fuji Electric FA components & Systems Co., Ltd./D & C Catalog Information subject to change without notice http://store.iiic.cc/ 08/35 Low Voltage Fuses BLC, CR and CS types Super Rapid Fuses Specifications Rated Intercurrent rupting capacity (A) 4700 2000 3000 40 75 100 150 200 250 300 350 400 450 500 600 800 1000 1000 1200 1200 1500 1000 1200 1500 80 100 150 200 250 300 350 400 500 560 630 750 800 1000 1250 1500 450 630 900 1250 Note: (kA) 150 at 125V AC 150 at 250V AC 200 at 500V AC Max. Watt interrupting I2t loss Fuse-link (Amp2xsec.) x 103 14000 1950 5500 1 3.5 5 10 18.5 33 64 85 122 131 159 257 600 1200 843 1800 1311 3600 200 at 1800 800V AC 2500 4400 200 at 10 1000V AC 16 37 63 110 148 211 307 420 410 450 640 1259 1722 2250 3200 100 at 350 1500V AC 760 1400 3050 Specifications (UL-recognized, CSA certified, TUV) Rated Rated current voltage Interrupting capacity Type (W) 310 CS1F-4700 124 216 6.4 12 17 25 34 42 45 56 57 62 73 80 114 110 167 114 200 209 125 176 220 17 21 27 37 44 53 70 74 90 102 135 156 211 245 330 334 134 170 280 350 CS2F-2000 CS2F-3000 CS5F-40 CS5F-75 CS5F-100 CS5F-150 CS5F-200 CS5F-250 CS5F-300 CS5F-350 CS5F-400 CS5F-450 CS5F-500 CS5F-600 CS5F-800 CS5F-1000 CS5F-1000-P CS5F-1200 CS5F-1200-P CS5F-1500 CS8F-1000 CS8F-1200 CS8F-1500 CS10F-80 CS10F-100 CS10F-150 CS10F-200 CS10F-250 CS10F-300 CS10F-350 CS10F-400 CS10F-500 CS10F-560 CS10F-630 CS10F-750 CS10F-800-P CS10F-1000-P CS10F-1250-P CS10F-1500-C CS15F-450 CS15F-630 CS15F-900-P CS15F-1250-P (A) 10 20 30 50 75 100 150 200 260 350 400 450 500 550 600 20 30 (kA) 250V AC 10 at AC 400V DC (pf: 0.8) 10 at DC (L/R: 2ms) 600V AC 100 at AC 680V DC (pf: 0.8) 10 at DC (L/R: 2ms) 50 75 100 150 100 at AC (pf: 0.8) 50 at DC (L/R: 2ms) 200 300 Note: Max. interrupting I2t Fuse-link (Amp2xsec.) x 103 Type 0.04 0.17 0.35 0.85 2.3 4.0 (W) 1.2 3.0 4.0 6.0 9.0 12.0 CR2LS-10/UL CR2LS-20/UL CR2LS-30/UL CR2LS-50/UL CR2LS-75/UL CR2LS-100/UL 9.5 17 27 60 103 140 160 200 215 0.14 18.0 23.0 30.0 37.0 39.0 46.0 48.0 51.0 56.0 4.0 CR2L-150/UL CR2L-200/UL CR2L-260/UL CR2L-350/UL CR2L-400/UL CR2L-450/UL CR2L-500/UL CR2L-550/UL CR2L-600/UL CR6L-20/UL 0.35 7.0 CR6L-30/UL 1.8 3.0 7.0 18 9.0 12.5 15.0 22.0 CR6L-50/UL CR6L-75/UL CR6L-100/UL CR6L-150/UL 30 34.0 CR6L-200/UL 95 40.0 CR6L-300/UL * Peak arc voltage CR2LS, CR2L .... Max. 500V CR6L .................. Max. 1200V * The peak arc voltage is obtained by interruption caused by the listed interrupting current at rated voltage. * This indcates the values when the conductors specified in UL Standards are connected and rated current apply. * TUV: CR2LS, 2L: Up to 350A CR6L: 50 to 300A CR type fuse with optional accessory Fuse with blown indication fuse CR2L (S)- G * Peak arc voltage CS1F ..... Max. 450V CS2F ..... Max. 750V CS5F ..... Max. 1000V CS8F ..... Max. 2000V CS10F ... Max. 2000V CS15F ... Less than 3000V * An alarm contact block AHX2905 (1NO) or AHX2915 (1NC) can be attached to CS type. (Sold separately) See page 08/44. Note: UL recognized fuse In the UL recognized fuses, a fuse with a blown inidcation fuse, or a fuse both with a blown indication fuse and a precision switch is also UL recognized. Examples: CR2L-200G/UL CR2LS-30S/UL CR6L-100G/UL AF88-446 Fuse with blown indication fuse and precision switch Precision switch (SPDT) CR2L (S)- S CRX-1 precision switch AF88-445 08/36 Watt loss AF88-442 Fuji Electric FA components & Systems Co., Ltd./D & C Catalog Information subject to change without notice http://store.iiic.cc/ Low Voltage Fuses BLC, CR and CS types Super Rapid Fuses Dimensions, mm BLC D BLC045 oD oD B B B A A B BLC075 to 140 C BLC012, 020, 023 oD CR2L-450 or smaller, CR2LS E A od od Mounting hole a x b od H Rated current (A) BLC012-1 12 BLC020-1 20 BLC023-1 23 BLC045-1 45 BLC075-1 75 BLC090-1 90 BLC120-1 120 BLC140-1 140 Note: A B 50 50 50 50 63 63 63 63 10 10 10 10 6 6 6 6 oD 13 13 13 27 34 34 47 47 od 10 14 14 20 5 8 8 8 Color of indicator Mass (g) Grey Yellow Violet White Silver Red Yellow Light red 12 12 12 62 120 120 120 215 The BLC type fuse link requires a holder in use. The size of the holder differs according to the fuse ratings. Select the most suitable one after referring to the Table on page 08/44. For drawings see page 08/32. Ordering information Specify the following: 1. Type number Type number nomenclature BLC 012-1 Rated current: 12 to 140A Plug-in type super rapid fuse CS 10F-1000 -P/ UL UL recognized (CR2L, CR2LS, CR6L) CSA certificated (CR2LS) TUV (CR2LS, CR2L, CR6L) Blown indicatin fuae (G type) G Type F A Type A CR2L-30 CR2L-50 CR2L-75 CR2L-100 CR2L-125 CR2L-140 CR2L-150 CR2L-175 CR2L-200 CR2L-225 CR2L-260 CR2L-300 CR2L-325 CR2L-350 CR2L-400 CR2L-450 CR2LS-10 CR2LS-20 CR2LS-30 CR2LS-50 CR2LS-75 CR2LS-100 B C D 80 58 18 80 58 E axb F 21.5 37 9x11 90 1.5 26.5 20 30.5 44 9x11 90 3 85 60 25 33.5 47 11x13 93 3.2 33.5 130g 95 70 30 42 11x13 98 4 39 220g 56 42 12 18.5 34.5 6.5x8.5 78 2 25 28g 54 G H Mass 42g 32.5 100g 08 CR2L-500 to -600 70 84 2-fuse connected parallel o37 30 Mounting hole 11x13 Rated current 10 to 4700A 41.5 43 46 6L: 2F: 8F: 15F: 600V AC 250V AC 800V AC 1500V AC 98 84 Blown indication fuse (G type) 8 Rated voltage 2L, 2LS: 250V AC, 1F: 150V AC, 5F: 500V AC, 10F: 1000V AC, 46.5 28 54 31 Optional accessory (See page 08/44) G: With blown indication fuse S: With blown indication fuse and precision switch CR: Barrel-shaped super rapid fuse CS: Cubic-shaped super rapid fuse Mass: 450g 95 Dimensions for reference only. Confirm before construction begins. Note: The dimensions of the fuses with suffix. UL are the same as those of the standard ones. Fuji Electric FA components & Systems Co., Ltd./D & C Catalog Information subject to change without notice http://store.iiic.cc/ 08/37 Low Voltage Fuses BLC, CR and CS types Super Rapid Fuses Dimensions, mm CR6L-20, CR6L-30, CR6L-50 CR6L-75 to 300 62 CR6L-350 to 600 84 B H Mountng hole 6.5x8.5 25 88 74 30 Mountng hole 11x13 Blown indication D fuse (G type) 41.5 43 46 Mountng hole a x b 23.5 o37 54 C E 27 12 o17.5 47 18 34.5 18.5 B D 46.5 28 F 8 Blown indication fuse (G type) 76 Mass: 42g Type C A A A CR6L-75 CR6L-100 CR6L-150 B 95 70 CR6L-200 107 82 CR6L-250 CR6L-300 G 2 Blown indication fuse (G type) C D E 25 34 47 102 3.2 33.5 11x13 150 30 42 F G H 54 107 4 39 CS1F-4700 CS2F-2000, 3000 axb Mass (g) 11x13 246 Type A B C D Mass (g) CR6L-350 107 82 43 107 493 CR6L-400 CR6L-500 121 96 43 114 522 CR6L-600 121 96 47.4 114 545 CS5F-40 to 1500 CS10F-80 to 750 CS15F-450, 630 CS8F-1000, 1200, 1500 Alarm contact block 7 Alarm contat block AHX2905(NO) AHX2915(NC) Blown fuse indicator Blown fuse indicator 7 7 Alarm contact block 54.5 C C 84 max. 7 D D Blown fuse indicator 72 30 30 A A N.P. M B A A B 51 72 2-MIO M Mass: 800g Voltage Type 500V 08/38 A CS5F-40 CS5F-75 CS5F-100 CS5F-150 CS5F-200 47 CS5F-250 CS5F-300 CS5F-350 57 CS5F-400 CS5F-450 CS5F-500 CS5F-600 CS5F-800 72 CS5F-1000 CS5F-1200 CS5F-1500 72 B 47 51 51 51 C 42.5 47 54.5 54.5 (Max.) D Mass (g) 65.5 M8 320 70 77 77 M M8 M10 M12 Voltage Type A B C D M Mass (g) M12 1060 (Max.) 800V CS8F-1000 CS8F-1200 72 74 54.5 84 CS8F-1500 72 82 54.5 84 M8 1150 1000V CS10F-80 CS10F-100 47 71 42.5 65.5 M8 420 CS10F-150 CS10F-200 CS10F-250 57 74 47 70 M8 690 CS10F-300 CS10F-350 CS10F-400 CS10F-500 CS10F-630 CS10F-750 72 74 54.5 77 M10 1060 CS15F-450 CS15F-630 72 105 54.7 77 M10 1400 510 800 830 1500V Fuji Electric FA components & Systems Co., Ltd./D & C Catalog Information subject to change without notice http://store.iiic.cc/ Low Voltage Fuses BLC, CR and CS types Super Rapid Fuses Dimensions, mm CS5F-P CS10F-P, CS15F-P Characteristic curves BLC Melting time-current characteristic 7 Minute max.77 72 Time 72 40 5 H N.P. L 54.5 7 Alarm contat block M10 o15 Voltage Type H L Mass (g) 500V CS5F-1000-P CS5F-1200-P 51 69 1900 1000V CS10F-800-P CS10F-1000-P CS10F-1250-P 74 92 2420 1500V CS15F-900-P CS15F-1250-P 105 123 3100 max.77 Current (A) Operating time-current characteristic CS10F-1500-C 7 Second 86 158 M10 M10 Time 5 M10 107 108 89.5 Second Alarm contat block 99 74 Minute 7 40 72 08 o15 72 Mass: 2500g Current (A) Max. Let-through current (Peak value) kA Current-limiting characteristic Available current (Sym, rms) I eff. (kA) Fuji Electric FA components & Systems Co., Ltd./D & C Catalog Information subject to change without notice http://store.iiic.cc/ 08/39 Low Voltage Fuses BLC, CR and CS types Super Rapid Fuses Second CR6L-350 CR6L-400 CR6L-500 CR6L-600 CR6L-200 CR6L-250 CR6L-300 CR6L-150 CR6L-100 CR6L-50 CR6L-75 CR6L-30 Second Time Time Minute CR6L-20 CR6L Melting time-current characteristic Minute Characteristic curves CR2L, CR2LS Melting time-current characteristic Current (A) Second CR6L-20 CR6L-200 CR6L-20 CR6L-250 CR6L-20 CR6L-300 CR6L-350 CR6L-400 CR6L-500 CR6L-600 CR6L-150 CR6L-100 CR6L-50 CR6L-75 CR6L-30 Second Time Time CR6L-20 Minute Operating time-current characteristic Minute Operating time-current characteristic Current (A) Current (A) Current (A) Current-limiting characteristic Max. Let-through current (Peak value) kA Max. Let-through current (Peak value) kA Current-limiting characteristic Available current (Sym, rms) I eff. (kA) 08/40 Available current (Sym, rms) I eff. (kA) Fuji Electric FA components & Systems Co., Ltd./D & C Catalog Information subject to change without notice http://store.iiic.cc/ Low Voltage Fuses BLC, CR and CS types Super Rapid Fuses Time Second Second Time Minute CS2F Melting time-current characteristic Minute Characteristic curves CS1F Melting time-current characteristic Current ( x 103A) Current ( x 103A) Operating time-current characteristic Time Second Second Time Minute Minute Operating time-current characteristic 08 Current ( x 103A) Current-limiting characteristic Max. Let-through current (Peak value) kA Max. Let-through current (Peak value) kA Current-limiting characteristic Current ( x 103A) Available current (Sym, rms) I eff. (kA) Fuji Electric FA components & Systems Co., Ltd./D & C Catalog Information subject to change without notice http://store.iiic.cc/ Available current (Sym, rms) I eff. (kA) 08/41 Low Voltage Fuses BLC, CR and CS types Super Rapid Fuses Characteristic curves CS5F Melting time-current characteristic Second Second Time Time Minute Minute CS8F Melting time-current characteristic Current ( x 10A) Current ( x 103A) Operating time-current characteristic Second Second Time Time Minute Minute Operating time-current characteristic Current ( x 10A) Current ( x 103A) Current-limiting characteristic Max. Let-through current (Peak value) kA Max. Let-through current (Peak value) kA Current-limiting characteristic Available current (Sym, rms) I eff. (kA) Available current (Sym, rms) I eff. (kA) 08/42 Fuji Electric FA components & Systems Co., Ltd./D & C Catalog Information subject to change without notice http://store.iiic.cc/ Low Voltage Fuses BLC, CR and CS types Super Rapid Fuses Second Second Time Time Minute CS15F Melting time-current characteristic Minute Characteristic curves CS10F Melting time-current characteristic Current ( x 10A) Current ( x 103A) Operating time-current characteristic Second Second Time Time Minute Minute Operating time-current characteristic 08 Current ( x 10A) Current ( x 103A) Available current (Sym, rms) I eff. (kA) Current-limiting characteristic Max. Let-through current (Peak value) kA Max. Let-through current (Peak value) kA Current-limiting characteristic Available current (Sym, rms) I eff. (kA) Fuji Electric FA components & Systems Co., Ltd./D & C Catalog Information subject to change without notice http://store.iiic.cc/ 08/43 Low Voltage Fuses BLC, CR and CS types Super Rapid Fuses Operating indication Blown fuse indication FUJI Super Rapid Fuses are available in BLC, CR and CS types. These types have different methods of indicating a blown fuse. BLC type A blown fuse is indicated by the color tip on the ferrule of the fuse being ejected as shown in Fig. 1. This can be seen through the window of the fuse holder. CR type This fuse does not have a blown indicator but if a trigger fuse is connected as shown in Fig. 2 this will provide the alarm for blown fuse. CS type This fuse is provided with a blown fuse indicator. In this case a pin in the contact pad is ejected after the fuse has been blown. If electrical connections for lamps or alarms are required fit the contact block (1NO or 1NC) to the pad as shown in Fig. 3. Fig. 3 Fig. 1 Alarm contact block AHX2905, 2915 SD-36 BLC type Fig. 2 CS10F SM-385 Line Alarm circuit Trigger fuse F Alarm circuit R SH-384 CS 10F with alarm contact block AF88-446 Load CR type Alarm contact block ratings Type Contact AHX2905 1NO AHX2915 1NC Rated voltage (V) AC Inductive cos=0.3~1 Rated operational Rated current (A) capacity (VA) 24 110 220 440 550 Fuse holder for BLC type fuse FUJI BLC fuses require special holders. Select the most suitable one which corresponds to the rated current of the fuse. Dimensions: See page 08/32. SD-36 Fuse link BLC 08/44 6 6 6 2.5 2 150 660 1320 1100 1100 Fuse link Rated current DC Resistive load Rated operational Rated current (A) capacity (W) 6 2.5 1 0.4 0.3 Type (A) Base Surface connection Type BLC012-1 BLC020-1 BLC023-1 BLC045-1 BLC075-1 BLC090-1 BLC120-1 BLC140-1 12 20 23 45 75 90 120 140 AFa30 AFa30 AFa30 AFa60 AFa100 AFa100 AFa200 AFa200 Inductive load Rated operational Rated current (A) capacity (W) 150 275 220 175 165 6 1.3 0.45 0.2 0.15 150 140 100 85 85 Screw cap Rear connection Type Adaptor ring Type Type Ba30 Ba30 Ba30 Ba60 Ba100 Ba100 Ba200 Ba200 Pa30 Pa30 Pa30 Pa60 Pa100 Pa100 Pa200 Pa200 R20 - - - R75 - - - AF88-439 Fuse holder Surface connection Fuji Electric FA components & Systems Co., Ltd./D & C Catalog Information subject to change without notice http://store.iiic.cc/ Low Voltage Fuses BLC, CR and CS types Super Rapid Fuses Fig. (a) Fuse ratings When selecting fuses various factors such as protection, coordination and load, etc. must be considered. However, in this catalog the main matters such as voltage, current and I 2t only are explained. Line fuse method In this method the fuses are connected to the AC line side. Rated voltage The rated voltage of the fuse indicates the maximum operational voltage and this also indicates the root-meansquare value of the AC sinusoidal wave voltage. Select fuses having a rated voltage exceeding the voltage obtained by the formula shown in the following table. (Fig. 1) Do not select current-limiting fuses with rated voltages drastically exceeding the rectifier circuit voltage. It is necessary to consider the arc voltage. Application and selection guide BLC, CR and CS-type - Super rapid fuse When selecting fuses for semiconductor rectifier circuit protection the following conditions must be satisfied. For additional details contact FUJI. Conditions of application 1. The rated interrupting current of the fuse must be greater than the estimated short circuit current of the circuit. Available short circuit current of rectifier circuit < Fig. (b) Rated interrupting current of fuse 2. The let-thru current value of fuse must be less than the allowable 1/2 cycle surge current value. Fuse let-thru current value < = Semiconductor - 1/2 cycle allowable surge current 10ms (at 50Hz) 3. The total clearing I2t value which the fuse requires to complete interruption must be less than the allowable I2t value of semiconductor. Fuse - total clearing I2t < = Semiconductor - I2t 4. The rated current of the fuse must be greater than the average forward current of the semiconductor. Fuse - rated current > Element fuse method In this method the fuses are connected in series to the semiconductor element. Fig. 1 Rated voltage required by fuses Wire connection type Single-phase bridge Wiring diagram Rated voltage of Fuse (VFN rms) For line fuse For element fuse Ea VFN > = a * Ea VFN > = a * Ea VFN > = a * Ea VFN > = a * 3 * Ea VFN > = a * 3 * Ea Semiconductor - average forward current Ea 3-phase bridge 5. The rated current and voltage of the fuse must be greater than those of the rectifier circuit. Fuse - rated current and voltage VFN > = a * Ea Ea > Rectifier circuit - current and voltage Method of application Semiconductor rectifier equipment has a variety of rectifier circuits. Taking the 3-phase bridge rectifier circuit as an example - Fig. (a) and (b) as shown in the following. Although the number of fuses used in the line fuse method (a) is half the number used in the element fuse method (b), the fuses must have a larger current capacity. 3-phase, double star Remarks: The 'a' is a coefficient where the regulation of the AC input voltage is taken into account. This is a=1.1 in case of voltage regulation 10%. Fig. 2 Element current and line current Wire connection type Wiring diagram Element fuse method Element current Ia Id Single-phase bridge I Id I 3-phase bridge 3-phase, double star Fuji Electric FA components & Systems Co., Ltd./D & C Catalog Information subject to change without notice http://store.iiic.cc/ Id Ia = __ 2 = 0.707d Ia Ia Ia I Id Id Ia = __ 3 = 0.577dI Line fuse method Line current I I =d 2 Id 3 = 0.816dI I = Id__ 2 3 = 0.289dI I = Ia = 08/45 08 Low Voltage Fuses BLC, CR and CS types Super Rapid Fuses Example I2t All I2t values are ampere2 seconds. 08/46 Peak let-thru current (Actual short-circuit current) Calculation Peak current of first half cycle of available peak current (AC component) Short circuit current that would pass without currentlimiting fuse. DC component From the table (Page 08/38), the fuse with a total I2t nearest to 30,400A2 Sec. is the 260 Ampere fuse (CR 2L-260). Current Maximum I2t diode = ( 1 Peak )2 0.0167 2 = ( 2700 )2 0.0167 2 = 30,400A2 Sec. Interrupting current The rated interrupting current of the fuse must exceed the maximum value (Symmetrical RMS value) of the estimated circuit fault current. Time M A T Current limitation Select a fuse whose let-thru current value does not exceed the allowable 1/2 cycle surge current of the semiconductor. The allowable surge current is the peak value of the current which in case at 50Hz is allowed to flow for 10ms. In the current-limiting fuse the fault must be cleared in the shortest possible time or in the first 1/2 cycle. Available current is the current which would flow if the fuse were not currentlimiting. This would cause damage to equipment. Let-thru current is the actual current allowed to flow by the current limiting action of the fuse. A number of let-thru current graphs are given in this catalog and example is given in the following paragraph. The method of reading this graph is provided for your reference. How to find a let-thru current - Example Fuse: 200 Amps 500V Available R.M.S symmetrical current: 100,000 Amps Available pe ak 105,000 11,600 st an ta ne ou s Peak arc voltage In the case of the current-limiting fuse an arc voltage (overvoltage) is generated at the time of interruption due to its fusible element construction. It is necessary to check that this peak arc voltage does not exceed the semiconductor's maximum (Nonrepetitive peak) reverse voltage value. cu rre nt Pf =1 M:Melting time A :Arcing time T :Total clearing time Let-thru 200A in Total clearing I t The total clearing I 2 t of fuse is a very important factor when considering the protective coordination of the semiconductor. This total clearing I 2t is the value where the arcing I 2 t is added to the melting I 2t. Therefore it is necessary to satisfy the following formula. Fuse - total < Semiconductor clearing I2t = I2t The total clearing I 2 t of fuse depends upon the operational voltage and interrupting current. Therefore, for this reason if a 500 Volts fuse is used in a 300 Volts circuit the total clearing I2t is reduced by 50-70%. However, the reduction rate varies according to the type of fuse construction. This must be checked and confirmed once more. Let-thru peak current (Instantaneous): 11,600 Amps Let-thru R.M.S. current 11,600 / 1.7 = 6,800 Amps This example clearly shows that while a 100kA (rms, sym) current is available, the fuse limits the current letthru to 6,800 Amperes (rms, sym). Av ai la bl e 2 The I2t data for silicon diodes or thyristor elements are normally given in their respective catalogs. If the A 2S data is not given in their catalog obtain the value in the following manner. If protection is needed for a 250V, 150A (Io) diode having a maximum allowable peak half sine wave current of 2700A, it is important that the fuse has a total I 2 t value lower than that of the diode. Let-thru peak current(Amperes)-Peak Rated current The current values in fuses in the line fuse system and the element fuse system are different. Obtain the correct current value from the table on page 08/48 (Fig. 2). When selecting the rated current of a fuse choose a fuse having an amperage rating greater than the current which flows in the semiconductor if the load is continuous and a fixed current. If the current which flows in the semiconductor is greater than the rated current of the fuse connect the fuses in parallel. However, in this case, if the numbers of fuses arranged in parallel are 'n', then the I2t value of the fuse will be n2*I2t and n2 times the I2t value of one fuse. This should be taken into consideration when protective coordination is taken into account. In the case of the circuit where the load rapidly varies the fuse element will suffer from mechanical deterioration and be damaged by thermal stress. In loads of this type the deterioration characteristics of the fuse must be closely considered. Moreover if the fuse current - time characteristics of the fuse selected is less than the overload characteristics of the semiconductor element then complete protection can be obtained. However, if the semiconductor element has a large capacity then protective cooperation is very difficult to arrange. The fuses are used to isolate the shorted semiconductor element circuit from sound operating circuits. 100,000A Available RMS symmetrical current(Ampere) Fuji Electric FA components & Systems Co., Ltd./D & C Catalog Information subject to change without notice http://store.iiic.cc/