compact flameproof power wirewound resistors wp-s series small size for power rating enhanced pulse handling capability flameproof protection smd z-form available rohs compliant with pb-free terminations general note welwyn components reserves the right to make changes in product specification without notice or liability. all information is subject to welwyn s 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 issue e ?07.06 a subsidiary of tt electronics plc welwyn components dimensions (mm) & weight (g) type l max d max f min d nom pcb min wt. mount bend nom centres radius wp1s 6.2 2.8 21.20 0.6 10.20 0.6 0.22 wp2s 9.0 3.6 19.80 12.70 0.50 wp25s 12.5 4.5 17.80 18.40 0.50 wp3s 14.5 5.2 24.55 20.30 1.10 wp4s 13 5.6 22.75 18.90 1.00 wp5s 16.5 7.0 23.55 22.86 1.75 wp7s 25.0 8.8 28.30 31.40 4.40 a high purity ceramic substrate is assembled with interference fit end caps to which are welded the terminations. the resistive element is wound on the substrate and welded to the caps. flameproof silicone cement coating is applied prior to marking with indelible ink. the components are then leadformed if required and packed. electrical data physical data construction d d lf wp1s wp2s wp25s wp3s wp4s wp5s wp7s power rating at 25? watts 1 2 2.5 3 4 5 7 5s overload rating at 25? watts 5 10 12.5 15 20 25 35 short pulse performance see pulse performance graphs resistance range ohms r068 to 430r r05 to 900r r05 to 900r r01 to 2k2 r01 to 10k r015 to 6k8 r15 to 10k limiting element voltage volts 50 50 75 100 100 150 150 tcr ppm/? <1r: 350 1r: 200 isolation voltage volts 250 350 500 700 resistance tolerance % standard values e24 preferred thermal impedance ?/watt 140 110 90 82 62 54 35 ambient temperature range ? -55 to +155 <20r: 5 20r: 1, 2, 5 <20r: 5 20r: 1, 2, 5 compact flameproof power wirewound resistors wp-s series welwyn components performance data maximum typical change load at rated power: 1000hrs @ 25? ? r% 5 +0.001 ? 3 dry heat: 1000hrs @ 200? ? r% 5 +0.001 ? 3 short term overload (5 x pr for 5s) ? r% 5 +0.001 ? 1 derating from rated power @25? zero at 280? climatic ? r% 5 +0.001 ? 2 climatic category 55/200/56 trc & vibration ? r% 5 +0.001 ? 1 robustness & solder heat ? r% 5 +0.001 ? 1 long term damp heat (56 days) ? r% 5 +0.001 ? 1 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 terminations wp1s, wp2s, wp25s and wp3s resistors r10 and above are marked with four or five colour bands in conformance with iec62. values below r10 are marked with three bands (two digits indicating value in milliohms, and tolerance); there is no multiplier band. wp4s, wp5s and wp7s resistors are legend marked with type reference, resistance value and tolerance. marking the body protection and marking are resistant to all normal industrial cleaning solvents suitable for printed circuits. solvent resistance the resistor coating will not burn or emit incandescent particles under any condition of applied temperature or power overload. flammability the pulse energy capacity limits in the graph below relate to pulses below 100ms duration, low mean power dissipation and at 25?. pulse performance ?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 issue e ?07.06 100 wp-s short pulse energy capacity value (ohms) 10 1 0.1 0.1 1 10 100 1000 10000 energy (joules) wp7s wp5s wp4s wp3s wp2s wp1s wp25s
1. if the resistors are to dissipate full rated power, it is recommended that the terminations should not be soldered closer th an 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 at the center of the body can be calculated using the thermal impedance figures given under electrical data. 3. wp-s resistors can also be supplied with radial, goalpost or lancet pre-formed leads. wp2s, wp3s, wp4s and wp5s are also available in an smd format with z formed leads and packed in blister tape. consult factory for details. application notes radial goalpost lancet z-form compact flameproof power wirewound resistors wp-s series welwyn components ?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 issue e ?07.06 the standard packaging for wp-s 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 boxes or onto reels; see ordering procedure for details. alternative packaging is available by request. pre-formed resistors are supplied loose packed in plastic bags or b oxes. packaging dimensions (mm) b c wp1s 52 5 wp2s 52 5 wp25s 52 5 wp3s 67 10 wp4s 63 10 wp5s 63 10 wp7s 85 10 figure 1 66 c b f1 f2 body location f1 - f2 1.4mm <
com pa c t fla m e p r o o f p o w e r w i r e woun d r e sist o r s w p- s s e ri e s w elwyn components example: wp2s at 680 ohms and 5% tolerance in ammo pack box of 2500 pieces - o r d e r i n g p r oc e d u r e ? w elwyn components limited bedlington, northumberland ne22 7aa, uk t elephone: +44 (0 ) 1670 822181 facsimile: +44 (0 ) 1670 829465 email: info@welwyn-tt.com w ebsite: ww w .welwyn-tt.com issue e 07.06 t ype wp2 s ? 680 r j a25 v alue (use iec 62 code) t olerance (use iec 62 code) packing f 1% g 2% j 5% a 5 wp1 s 5000/box a2 5 wp2 s 2500/box a1 5 amm o wp25 s 1500/box a 1 wp3 s 1000/bo x standa r d a 1 wp4 s 1000/box t0 7 t ap e wp5 s 750/ r eel wp7 s 700/ r eel t0 7 5 t ape
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