cement coated wirewound resistors w30 series c 1% tolerance c flameproof cement coating c all welded construction c high reliabilty c ideal for automotive applications and power supplies electrical data w31 notes power rating at 25c watts 3.0 power rating at 70c watts 2.5 resistance range ohms 0.01 to 10k tcr (-55 to 155c) ppm/c see below resistance tolerance % 5 2 1 standard values e24 series preferred other values to special order thermal impedance c/watt 83 ambient temperature range c -55 to 155 limiting element voltage volts 100 tcr ppm/c 0.01 ohms <1000 0.033 ohms <500 0.091 ohms <200 10 ohms <150 10k ohms <100 physical data dimensions (mm) and weight (g) wt. type l max. d max. f min. d nom. nom. w31 13 5.6 22.75 0.8 1.0 construction a high quality ceramic substrate is assembled with interference fit end caps to which are welded the element winding and termination wires. the protection is then applied to the body, providing an effective seal which is impervious to moisture, shock, vibration, fungus and salt spray. terminations material solder-coated copper clad steel 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. ? welwyn components limited bedlington, northumberland ne22 7aa, england tel: 01670 822181 fax: 01670 829465 web: http://www.welwyn-tt.co.uk issue a 07/9 9 general note welwyn components reserves the right to make changes in product specification without notice or liability. all information is subject to welwyns own data and is considered accurate at time of going to print. l d f d dia marking w31 resistors are legend marked with type reference, resistance value and tolerance. values are marked in accordance with iec 62. solvent resistance the body and marking are resistant to all normal industrial cleaning solvents suitable for printed circuits. flammability the resistor coating will not burn under any condition of applied temperature or component overload.
a f 1 f 2 6 6 10 0.5 f 1 ?f 2 1.4 mm performance data maximum typical load: 1000 hrs 3 watts @ 25c ? r% 5.0 + .001 3.5 1000 hrs 2.5 watts @ 70c ? r% 5.0 + .001 3.5 dry heat: 1000 hrs at 200c ? r% 5.0 + .001 3.5 derating from room temperature see derating curve short term overload 10 x rated power for 5 seconds ? r% 5.0 + .001 1.0 climatic ? r% 5.0 + .001 3.5 climatic category 55/200/56 long term damp heat: 56 days ? r% 3.0 + .001 1.0 temperature rapid change ? r% 2.0 + .001 1.5 resistance to solder heat ? r% 5.0 + .001 2.0 vibration and bump ? r% 5.0 + .001 2.0 voltage proof volts 500 min pulse handling data available by request application notes the terminations should not be bent closer than 1.6mm from the body, and the recommended minimum bend radius is 1.2mm. care must be taken when determining clearance between the resistor body and the p.c.b. or other components. resistance is measured 6mm from body. packaging the standard method of packaging is taped in ammopacks. alternatives available by request are: -taped and reeled - loose packed in boxes (minimum lead length 30mm) w31 resistors can be supplied preformed. contact factory for details. cement coated wirewound resistors w30 series ? welwyn components limited bedlington, northumberland ne22 7aa, england tel: 01670 822181 fax: 01670 829465 web: http://www.welwyn-tt.co.uk issue a 07/9 9 20 40 60 80 100 120 140 160 180 200 220 240 260 280 130 120 110 100 90 80 70 60 50 40 30 20 10 0 temp wa30 series derating curve % of rated power at 70 standard quantities per package type w31 ammopack 1000 reel 1000 type a w31 63 2
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