ulw2 ulw3 ULW4 power rating at 25c watts 2 3 4 5 second overload rating at 25oc watts 10 15 20 inrush / surge performance see pulse performance graphs resistance range ohms 22 to 100 10 to 100 10 tcr ppm/c 200 isolation voltage volts 250 350 500 resistance tolerance % 5 ul recognised standard values ohms 22, 33, 47, 68, 100 10, 22, 27, 33, 47, 68, 100 10 thermal impedance c/watt 110 82 62 ambient temperature range c -55 to +155 we lwyn c omponent s a subsidiary of tt electr onics plc general note welwyn components reserves the right to make changes in product specifcation without notice or liability. all information is subject to welwyns own data and is considered accurate at time of going to print. ? welwyn components limited bedlington, northumberland ne22 7aa, uk telephone: +44 (0)1670 822181 facsimile: +44 (0)1670 829465 email: info@welwyn-tt.com website: www.welwyn-tt.com 03. 09 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 min bend radius ulw2 9.0 3.6 19.8 0.8 12.7 1.2 0.5 ulw3 14.5 5.2 24.6 20.3 1.1 ULW4 13 5.6 22.8 18.9 1.0 note - no limiting element voltage applies; maximum continuous voltage is (p.r) 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 resistors are legend marked with type, value and tolerance. d f l d
we lwyn c omponent s ? welwyn components limited bedlington, northumberland ne22 7aa, uk telephone: +44 (0)1670 822181 facsimile: +44 (0)1670 829465 email: info@welwyn-tt.com website: www.welwyn-tt.com 03. 09 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. 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 te mp er at ur er is e 0 50 10 0 15 0 20 0 25 0 01 23 4 po we r( w) te m p e ra t u re ri s e( c) de ra ti ng cu rv e 0 20 40 0 0 10 0 05 01 00 15 02 00 25 03 00 am bi en tt em pe ra tu re ( c) pr o po rt i o no f ra te dp o w e r( %) ulw2 ul w 3 ul w 4
we lwyn c omponent s ? welwyn components limited bedlington, northumberland ne22 7aa, uk telephone: +44 (0)1670 822181 facsimile: +44 (0)1670 829465 email: info@welwyn-tt.com website: www.welwyn-tt.com 03. 09 ul recognised wirewound resistors ulw series pulse performance fusing performance 1. 2/ 50 sp eakv ol ta ge li mi t (1 0p ul se sa t1 0s in te rv al s r 5% ) no te t he vo lt ag es ho wn is th en et tv ol ta ge ac ro ss th e re si st or .t he ge ne ra to ro pe nc ir cu it vo lt ag ew il lb eh ig he r du et o th eg en er at or si nt er na li mp ed an ce . 0 1 2 3 4 5 01 02 03 04 05 0 0 0 0 01 00 va lu e( oh ms ) pe ak vo lt ag e( kv ) pu ls ee ne rg yl im it (s in gl eo rl ow re pe ti ti on ra te r 5% ) 0 1 2 3 4 5 01 02 03 04 05 0 0 0 0 01 00 va lu e( oh ms ) pu ls ee ne rg y( j) ul w2 ul w2 ul w 3 ul w 3 ul w4- 10rj ha sa ne nerg yl im it of 4. 3j an da 1. 2/ 50 sp ea kv ol ta ge limi to f1 .1 kv . ul w2 fu sing ch ar ac te ri st ic 0 10 20 30 40 50 0 30 35 40 45 50 55 0 in itia lp ow er (w ) ma x im um fu si ng ti me (s ) no te s: 1. ty pi ca lf us in gt im es ar ea ro un d1 /3 of th em ax im um fi gu re s. 2. af te rf us in gt he re si st an ce va lu ei s 10 0t im es th ei ni ti al no mina lv al ue . 3. u it ab le fo rf us in ga tv ol ta ge su pt o2 4 vr ms . ul w3 & ul w4 fu si ng ch ar ac te ri stic 0 10 20 30 40 50 0 50 0 0 0 0 10 0 1 10 12 0 init ia lp ow er (w ) ma xi mu mf u si ng ti me ( s )
we lwyn c omponent s ? welwyn components limited bedlington, northumberland ne22 7aa, uk telephone: +44 (0)1670 822181 facsimile: +44 (0)1670 829465 email: info@welwyn-tt.com website: www.welwyn-tt.com 03. 09 ul recognised wirewound resistors ulw series 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. 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. 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 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 j 5% f1 f2 6 6 c f body location f1 - f2 < 1.4mm figure 1 b
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