ULW2

UL Recognised Wirewound Resistors ULW Series Welwyn Components · · · · · · UL1412 recognised fusible resistor * Failsafe mains fusing at 120 / 240Vrms Inrush and surge withstanding UL94-V0 flameproof coating SMD leadform option available RoHS compliant * UL file number E234469. Electrical Data ULW2 Power rating at 25°C 5 second overload rating at 25ºC Inrush / surge performance Resistance range TCR Isolation voltage Resistance tolerance UL recognised standard values Thermal impedance Ambient temperature range ohms ppm/°C volts % ohms °C/watt °C 22, 33, 47, 68, 100 110 250 22 to 100 watts watts 2 10 ULW3 3 15 See Pulse Performance graphs 10 to 100 ±200 350 5 10, 22, 27, 33, 47, 68, 100 82 -55 to +155 10 62 500 10 ULW4 4 20 Note - no limiting element voltage applies; maximum continuous voltage is √(P.R) Physical Data Dimensions (mm) and weight (g) Type ULW2 ULW3 ULW4 L Max 9.0 14.5 13 D Max 3.6 5.2 5.6 f min 19.8 24.6 22.8 0.8 d nom PCB mount centres 12.7 20.3 18.9 1.2 Min bend radius Min bend radius 0.5 1.1 1.0 d D L f Construction A high purity ceramic rod is assembled with interference fit 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 five colour bands. The first four indicate value and tolerance in conformance with IEC62. The fifth yellow band denotes defined fusibility. ULW4 resistors are legend marked with type, value and tolerance. 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. A subsidiary of TT electronics plc © 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 Welwyn Components Terminations Material: Strength: Solderability: Hot tin dipped copper wire The terminations meet the requirements of IEC 68.2.21 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. Performance Data Maximum Load at rated power (1000 hours @ 25°C) Short term overload (5 x Pr for 5 seconds) Pulse (see Pulse Performance graphs) Climatic Long term damp heat (56 days) Climatic category Temperature rapid change Dry heat (1000 hours @ 200°C) Vibration Robustness & solder heat ΔR% ΔR% ΔR% ΔR% 5 5 5 5 ΔR% ΔR% ΔR% ΔR% ΔR% 5 5 5 5 5 55/200/56 1 3 1 1 Typical 3 1 2 2 1 Thermal Performance Derating Curve 250 Proportion of Rated Power (%) 100 80 60 40 20 0 0 50 100 150 200 250 300 Am bient Tem perature (°C) Temperature Rise (°C) 200 150 100 50 0 0 1 2 Pow er (W) 3 4 Body Temperature Rise ULW3 ULW2 ULW4 © 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 Welwyn Components Pulse Performance (single or low repetition rate, 8 7 Pulse Energy (J) 6 Pulse Energy Limit R