Cement Coated Wirewound Resistors Welwyn Components W30 Series * Values down to 10m ohms * Tolerance to 1% * Flameproof protection * Custom built to meet pulse requirements Electrical Data W31 Power rating at 25C watts Notes 3.0 Power rating at 70C watts 2.5 Resistance range ohms 0R01 to 10K TCR (-55 to 155C) ppm/C Resistance tolerance % Standard values See below <R10: 5 >=R10: 1, 2, 5 E24 series preferred Thermal impedance C/watt Ambient temperature range 83 C Limiting element voltage -55 to 155 volts TCR ppm/C Other values to special order 100 0.01 ohms <1000 0.033 ohms <500 0.091 ohms <200 10 ohms <150 10K ohms <100 Physical Data Maximum Dimensions (mm) and Weight (g) Type L max. D max. W31 13 5.6 (note 1) f min. 22.75 d nom. Wt.nom. 0.8 1.0 d D L f _0R1 Note 1: 5.8 for values < Construction Marking A high quality ceramic substrate is assembled with interference fit end caps to which are welded the element W31 resistors are legend marked with type reference, resistance value and tolerance. Values are marked in accordance with IEC 62. to the body, providing an effective seal which is impervious to moisture, shock, vibration, fungus and salt spray. Solvent Resistance Terminations The body and marking are resistant to all normal industrial cleaning solvents suitable for printed circuits. Material Strength Solderability Solder coated copper. The terminations meet the requirements of IEC 68.2.21. The terminations meet the requirements of IEC 115-1, Clause 4.17.3.2. Flammability The resistor coating will not burn under any condition of applied temperature or component overload. 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. (c) 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 A subsidiary of TT electronics plc Issue D * 07.06 99 Cement Coated Wirewound Resistors Welwyn Components W30 Series Performance Data Maximum Typical 1000 hrs 3 watts @ 25C R% 5.0 + .001 3.5 1000 hrs 2.5 watts @ 70C R% 5.0 + .001 3.5 R% 5.0 + .001 Load: Dry heat: 1000 hrs at 200C Derating from room temperature 3.5 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 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 Voltage proof volts Climatic category 55/200/56 Pulse handling Data available by request % of Rated Power at 70 W31 Series Derating Curve 130 120 110 100 90 80 70 60 50 40 30 20 10 0 2.0 500 min 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. 20 40 60 80 100 120 140 160 180 200 220 240 260 280 Temp 10 Packaging The standard method of packaging is taped in ammo packs. Can be provided on reels by request. W31 resistors can be supplied preformed. Contact factory for details. f1 6 f2 63 6 f1 - f2 1.4 mm Ordering Procedure Example: W31 at 1 kilohms and 1% tolerance packed in a box of 1000 pieces W31- 1K0FA1 Type Value (use IEC62 code) Tolerance (use IEC62 code) F G J 1% 2% 5% Packing A1 T1 Ammo Tape 1000/box 1000/reel Standard (c) 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 100 Issue D * 07.06