ULW4

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 www.DataSheet.net/ ULW3 3 15 See Pulse Performance graphs 10 to 100 ±200 350 5 10, 22, 27, 33, 47, 68, 100 82 -55 to +155 ULW4 4 20 10 500 10 62 watts watts 2 10 22 to 100 250 110 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 fo...