www.bitechnologies.com www.irctt.com www.welwyn-tt.com general note tt electronics reserves the right to make changes in product specifcation without notice or liability. all information is subject to tt electronics own data and is considered accurate at time of going to print. ? tt electronics plc 03.13 construction a high purity ceramic rod is assembled with interference ft end caps to which are welded the terminations. the surge withstanding resistive element is wound on the rod and welded to the caps. flameproof fusible cement coating is applied prior to marking with indelible ink. the components are then leadformed if required and packed. marking ulw2 & ulw3 resistors are marked with fve colour bands. the frst four indicate value and tolerance in conformance with iec62. the ffth yellow band denotes defned fusibility. ulw4 and ulw5 resistors are legend marked with type, value and tolerance. ulw2 ulw3 ulw4 ulw5 power rating at 25c watts 2 3 4 5 5 second overload rating at 25oc watts 10 15 20 25 inrush / surge performance see pulse performance graphs resistance range ohms 4r7 to 100 4r7 to 100 4r7 to 100 4r7-100 tcr ppm/c 200 isolation voltage volts 250 350 500 resistance tolerance % 5 ul recognised standard values ohms any value in range 4r7 to 100r is recognised. e24 preferred thermal impedance c/watt 110 82 62 54 ambient temperature range c -55 to +155 ul recognised wirewound resistors ulw series physical data ul1412 recognised fusible resistor * failsafe mains fusing at 120 / 240vrms inrush and surge withstanding ul94-v0 fameproof coating smd leadform option available rohs compliant * ul fle number e234469. electrical data dimensions (mm) and weight (g) type l max d max f min d nom pcb mount centres min bend radius wt. nom ulw2 9.0 3.8 19.8 0.8 12.7 1.2 0.5 ulw3 14.5 5.8 24.6 20.3 1.1 ulw4 13 5.6 22.8 18.9 1.0 ulw5 16.5 7.2 23.6 22.9 1.8 note - no limiting element voltage applies; maximum continuous voltage is (p.r) d f l d
ul recognised wirewound resistors ulw series terminations material: hot tin dipped copper wire strength: the terminations meet the requirements of iec 68.2.21 solderability: the terminations meet the requirements of iec 115-1 clause 4.17.3.2 solvent resistance the body protection and marking are resistant to all normal industrial cleaning solvents suitable for printed circuits. flammability the resistor coating will not burn or emit incandescent particles under any condition of applied temperature or power overload. * addition of 0.01 applies maximum* typical load at rated power (1000 hours @ 25c) r% 5 3 short term overload (5 x pr for 5 seconds) r% 5 1 pulse (see pulse performance graphs) r% 5 2 climatic r% 5 2 long term damp heat (56 days) r% 5 1 climatic category 55/200/56 temperature rapid change r% 5 1 dry heat (1000 hours @ 200c) r% 5 3 vibration r% 5 1 robustness & solder heat r% 5 1 performance data thermal performance body temperature rise 0 50 100 150 200 250 300 0 1 2 3 4 5 power (w) temperature rise (c) derating curve 0 20 40 60 80 100 0 50 100 150 200 250 300 ambient temperature (c) proportion of rated power (%) ulw2 ulw3 ulw4 ulw5 www.bitechnologies.com www.irctt.com www.welwyn-tt.com general note tt electronics reserves the right to make changes in product specifcation without notice or liability. all information is subject to tt electronics own data and is considered accurate at time of going to print. ? tt electronics plc 03.13
pulse value ohms e (j) 4.7 10 22 27 33 39 47 ulw3 5.3 4.3 3.2 3.9 5.3 2.8 4.9 ulw2 1.7 3.6 1 1.3 1.7 1.75 1.8 ulw5 9.73 10.42 11.35 9.51 8.89 10.3 12.66 0 2 4 6 8 10 12 14 0 10 20 30 40 50 60 70 80 90 100 pulse energy (j) value (ohms) pulse energy limit (single or low repetition rate, r<5%) ulw 5 ulw3 & 4 ulw2 pulse value ohms e (j) 4.7 10 22 27 33 39 47 ulw3 5.3 4.3 3.2 3.9 5.3 2.8 4.9 ulw2 1.7 3.6 1 1.3 1.7 1.75 1.8 ulw5 9.73 10.42 11.35 9.51 8.89 10.3 12.66 0 2 4 6 8 10 12 14 0 10 20 30 40 50 60 70 80 90 100 pulse energy (j) value (ohms) pulse energy limit (single or low repetition rate, r<5%) ulw 5 ulw3 & 4 ulw2 ul recognised wirewound resistors ulw series pulse performance fusing performance www.bitechnologies.com www.irctt.com www.welwyn-tt.com general note tt electronics reserves the right to make changes in product specifcation without notice or liability. all information is subject to tt electronics own data and is considered accurate at time of going to print. ? tt electronics plc 03.13 ulw5 value (ohms) 1.2/50s peak voltage limit (10 pulses at 10s intervals, r <5%) note the voltage shown is the nett voltage across the resistor. the generator open circuit voltage will be higher due to the generators internal impedence. ulw2 ulw3 & 4 0 10 20 30 40 50 60 70 80 90 100 5 4 3 2 1 0 peak voltage (kv) ulw2 fusing characteristic 40 30 35 45 50 55 60 60 50 40 30 20 10 0 initial power (w) maximum fusing time (s)
ul recognised wirewound resistors ulw series fusing performance ul w5 fusing characteristic 0 10 20 30 40 50 60 80 10 01 20 14 01 60 18 02 00 initial power (w ) maximum fusing time (s ) notes: 1. typical fusing times are around 1/3 of the maximum fgures. 2. after fusing the resistance value is >100 times the initial nominal value, provided the initial power is at least 20 x rated power. 3. suitable for fusing at voltages up to 264vrms. application notes application notes 1. if the resistors are to dissipate full rated power, it is recommended that the terminations should not be soldered closer than 4mm from the body. 2. due to operating temperature limits imposed by some pcb materials, derating may be necessary. an estimate of the temperature rise to be expected can be calculated using the thermal impedance fgures given under electrical data. 3. for the purposes of ul approval, the following points should be observed: 3.1 to protect against fre under all conditions of overload, a positive clearance of at least 13mm should be provided between the body of the resistor and any combustible materials. 3.2 a positive clearance of 13mm should be provided between the resistor body or terminations and uninsulated parts of opposite polarity or uninsulated dead metal parts. 3.3 limited short circuit testing should be performed in the complete appliance. www.bitechnologies.com www.irctt.com www.welwyn-tt.com general note tt electronics reserves the right to make changes in product specifcation without notice or liability. all information is subject to tt electronics own data and is considered accurate at time of going to print. ? tt electronics plc 03.13 initial power (w) ulw3 & ulw4 fusing characteristic maximum fusing time (s) 180 160 140 120 100 80 60 40 40 50 60 70 80 90 100 110 120 20 0
ul recognised wirewound resistors ulw series packaging the standard packaging for ulw is taped. the critical dimensions are shown in figure 1. the component wires will not protrude beyond the outside edge of the tapes. taped product is then packed into ammo boxes for ulw2, 3 and 4 or onto reels for ulw5. alternative packaging is available by request. pre-formed resistors are supplied loose packed in plastic bags or boxes. for smd leadformed option, see the z-form datasheet. dimensions (mm) type b c ulw2 52 5 ulw3 67 10 ulw4 63 10 ulw5 ordering procedure example: ulw2 at 33 ohms and 5% tolerance in ammo pack box of 2500 pieces - u l w 2 C 3 3 r j a25 type value (use iec62 code) tolerance (use iec62 code) packing a25 ammo ulw2 2500/box standard a1 ulw3, ulw4 1000/box t075 tape ulw5 750/reel j 5% f1 f2 6 6 c f body location f1 - f2 < 1.4mm figure 1 b www.bitechnologies.com www.irctt.com www.welwyn-tt.com eneral note tt electronics reserves the right to make changes in product specifcation without notice or liability. all information is subject to tt electronics own data and is considered accurate at time of going to print. tt electronics plc 03.13
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