Cement Coated Wirewound Resistors W30 SERIES ● 1% Tolerance ● Flameproof cement coating ● All welded construction ● High reliabilty ● Ideal for automotive applications and power supplies Electrical Data Power rating at 25°C Power rating at 70°C Resistance range TCR (-55 to 155°C) Resistance tolerance Standard values Thermal impedance Ambient temperature range Limiting element voltage TCR 0.01 ohms 0.033 ohms 0.091 ohms 10 ohms 10K ohms watts watts ohms ppm/°C % °C/watt °C volts W31 3.0 2.5 0.01 to 10k See below 5 2 1 E24 series preferred 83 -55 to 155 100 NOTES Other values to special order ppm/°C <1000 <500 <200 <150 <100 Physical data Dimensions (mm) and Weight (g) Type L max. D max. f min. W31 13 5.6 22.75 d nom. 0.8 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. Wt. nom. 1.0 d dia D L f 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. 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, England Tel: 01670 822181 Fax: 01670 829465 Web: http://www.Welwyn-TT.co.uk Issue A 07/99 Cement Coated Wirewound Resistors W30 SERIES Performance Data ∆R% ∆R% ∆R% ∆R% ∆R% ∆R% ∆R% ∆R% ∆R% volts MAXIMUM TYPICAL 5.0 + .001Ω 3.5 5.0 + .001Ω 3.5 5.0 + .001Ω 3.5 see derating curve 5.0 + .001Ω 1.0 5.0 + .001Ω 3.5 55/200/56 3.0 + .001Ω 1.0 2.0 + .001Ω 1.5 5.0 + .001Ω 2.0 5.0 + .001Ω 2.0 500 min 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. Type W31 WA30 Series Derating Curve 130 120 110 100 90 80 70 60 50 40 30 20 10 0 20 % of Rated Power at 70 Load: 1000 hrs 3 Watts @ 25°C 1000 hrs 2.5 Watts @ 70°C Dry heat: 1000 hrs at 200°C Derating from room temperature Short term overload 10 x rated power for 5 seconds Climatic Climatic category Long term damp heat: 56 days Temperature rapid change Resistance to solder heat Vibration and bump Voltage proof Pulse handling data 40 60 80 100 120 140 160 180 200 220 240 260 280 Temp A 63 ± 2 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. 10 ± 0.5 f1 PACKAGING The standard method of packaging is taped in ammopacks. Alternatives available by request are: 6 f2 A 6 f1 – f2 ≤ 1.4 mm -taped and reeled - loose packed in boxes (minimum lead length 30mm) W31 resistors can be supplied preformed. Contact factory for details. STANDARD QUANTITIES PER PACKAGE Type Ammopack Reel W31 1000 1000 © Welwyn Components Limited Bedlington, Northumberland NE22 7AA, England Tel: 01670 822181 Fax: 01670 829465 Web: http://www.Welwyn-TT.co.uk Issue A 07/99