High Speed Fuses British BS 88 -- 240V: 6-900A LCT, LET, LMT, LMMT Arc Voltage Specifications Description: BS 88 style stud-mount fuses. Dimensions: See dimensions illustrations. Ratings: Volts: -- 240Vac/150Vdc Amps: -- 6-900A IR: -- 200kA RMS Sym. Agency Information: CE, Designed and tested to: BS 88 Part 4, IEC 269 Part 4, UL Recognized. All fuses above have been tested at 318Vac. Consult Cooper Bussmann for specific UL Recognition status. Electrical Characteristics 1.6 Total Clearing I2t K 1.4 The total clearing I2t at rated voltage and at power factor of 15% are given in the electrical characteristics. For other voltages, the clearing I2t is found by multiplying by correction factor, K, given as a function of applied working voltage, Eg, (rms). 1.2 1.0 0.8 0.4 2) Eg 50 100 150 200 250 Fig. 2: LET 7.1 4 5.5 26.2 41.8 56 28 38 47 9.7 12.7 6.4 17.7 8.4 19.1 8.7 Fig. 4: LMMT Fig. 3: LMT 1mm = 0.0394" / 1" = 25.4mm 25.4 25.4 31 59 31 59 84 13.5 13.5 10.3 10.3 41 83 38.1 Indicator (Optional) 1) 500 2) 250 Eg 100 Watts loss at rated current is given in the electrical characteristics. The curve allows the calculation of the power losses at load currents lower than the rated current. The correction factor, Kp, is given as a function of the RMS load current, Ib, in % of the rated current. 300 1.0 Kp 0.8 0.6 0.5 0.4 0.3 0.2 Ib 0.1 30 40 50 38 84 Catalog Numbers 6LCT 10LCT 12LCT 16LCT 20LCT 25LET 32LET 35LET 50LET 63LET 80LET 100LET 125LET 160LET 180LETa 160LMT 200LMT 250LMT 315LMT 355LMT 400LMT 450LMT 400LMMT 500LMMT 630LMMT 710LMMT 800LMMT 900LMMT Type LCT LET LMT LMMT Rated Current RMS-Amps 6 10 12 16 20 25 32 35 50 63 80 100 125 160 180 160 200 250 315 355 400 450 400 500 630 710 800 900 Pre-arc 2 3.8 7 20 25 18 32 50 100 180 300 600 600 1100 1600 1100 1500 3200 6000 8000 14000 18000 6000 14000 24000 32000 52000 75000 60 70 80 90 100% I2t (A2 Sec) Clearing at 120V 6 12 22 50 80 120 200 320 500 1100 1900 3800 3800 7000 12000 7000 10000 20000 35000 50000 70000 100000 35000 80000 150000 200000 300000 400000 Clearing at 240V 9 22 32 100 160 250 450 600 1400 2200 3800 7500 7500 16000 29000 16000 20000 40000 75000 100000 160000 220000 80000 170000 300000 460000 600000 800000 Watts Loss 1.0 2.5 2.5 2.5 4.0 4.0 5.0 5.0 7.0 9.0 10.0 10.0 16.0 20.0 21.0 17.0 28.0 28.0 35.0 35.0 40.0 42.0 60.0 64.0 75.0 77.0 82.0 97.0 * Watts loss provided at rated current. * Note: 7LET, 10LET, 12LET and 16LET are available for replacement purposes on existing equipment. * See accessories on page 195. Features and Benefits * Excellent cycling capability * Excellent DC performance * Low arc voltage and low energy let-through (I2t) Typical Applications * DC common bus * AC and DC drives * Power converters/rectifiers * Reduced voltage starters Data Sheet: 720004 188 200 1) LCT 2) LET, LMT, LMMT Electrical Characteristics 1) 0.2 UL Power Losses Catalog Numbers 0.6 1) LCT 2) LET, LMT, LMMT Dimensions (mm) Fig. 1: LCT 750 This curve gives the peak arc voltage, UL, which may appear across the fuse during its operation as a function of the applied working voltage, Eg, (rms) at a power factor of 15%. For product data sheets, visit www.cooperbussmann.com/datasheets/ulcsa High Speed Fuses British BS 88 -- 240V: 6-900A LCT 6-20A: 240V LET 25-180A: 240V Time-Current Curve Time-Current Curve 104 6 4 104 6 4 2 2 103 103 6 4 6 4 2 6LCT 10LCT 12LCT 16LCT 20LCT 102 6 4 2 102 2 Virtual Pre-Arcing Time In Seconds 2 101 6 4 2 100 6 4 2 10-1 101 6 4 25LET 32LET 35LET 50LET 63LET 2 100 6 4 High Speed Fuses 2 10-1 6 4 6 4 2 2 10-2 10-2 6 4 6 4 2 2 10-3 6 4 10-3 6 4 2 2 10-4 2 4 6 8 2 4 6 8 101 102 Prospective Current In Amps RMS 2 4 6 8 10-4 103 2 101 4 6 8 102 2 4 6 8 103 Prospective Current In Amps RMS Data Sheet: 35785296 Data Sheet: 35785293 Peak Let-Through Curve 2 105 900LMMT 800LMMT 710LMMT 630LMMT 450LMT 400 & 500LMMT 355LMT 315LMT 250LMT 6 4 2 104 180LET 200LMT 160LET & LMT 125 & 100LET 80LET 6 Peak Let-Through Current Virtual Pre-Arcing Time In Seconds 80LET 100LET 125LET 160LET 180LETa 6 4 4 2 103 6 4 63LET 50LET 35LET 32LET 25LET 2 10 2 20LCT 16LCT 12LCT 10LCT 6LCT 6 4 2 SYMMETRICAL FAULT FULLY ASYMMETRICAL FAULT 101 101 2 4 6 102 2 4 6 103 2 4 6 104 2 4 6 105 Prospective Short-Circuit Current Symmetrical RMS For product data sheets, visit www.cooperbussmann.com/datasheets/ulcsa 189 High Speed Fuses British BS 88 -- 240V: 6-900A LMT 160-450A: 240V LMMT 400-900A: 240V Time-Current Curve Time-Current Curve 104 6 4 104 6 4 2 2 103 103 6 4 6 4 2 101 6 4 400LMMT 500LMMT 630LMMT 710LMMT 800LMMT 900LMMT 102 6 4 Virtual Pre-Arcing Time In Seconds 2 Virtual Pre-Arcing Time In Seconds 2 160LMT 200LMT 250LMT 315LMT 355LMT 400LMT 450LMT 102 6 4 2 100 6 4 2 10-1 6 4 2 101 6 4 2 100 6 4 2 10-1 6 4 2 2 10-2 6 4 10-2 6 4 2 2 10-3 10-3 6 4 6 4 2 2 10-4 102 2 4 6 8 103 2 4 6 10-4 8 104 2 102 Prospective Current In Amps RMS 4 6 8 103 2 Data Sheet: 35785294 Data Sheet: 35785295 Peak Let-Through Curve 2 105 900LMMT 800LMMT 710LMMT 630LMMT 450LMT 400 & 500LMMT 355LMT 315LMT 250LMT 6 4 2 10 4 180LET 200LMT 160LET & LMT 125 & 100LET 80LET Peak Let-Through Current 6 4 2 103 6 4 63LET 50LET 35LET 32LET 25LET 2 102 20LCT 16LCT 12LCT 10LCT 6LCT 6 4 2 SYMMETRICAL FAULT FULLY ASYMMETRICAL FAULT 101 10 1 2 4 6 102 2 4 6 103 2 4 6 104 2 4 6 105 Prospective Short-Circuit Current Symmetrical RMS 190 4 Prospective Current In Amps RMS For product data sheets, visit www.cooperbussmann.com/datasheets/ulcsa 6 8 104