WFH330L1K0JE

WFH Series L ø4.5 Aluminum Housed Wirewound Power 12.6 6.3 0.8 13.6 8 41 51 Amp terminal 15 Ohmite’s new flat core winding technology allows for wirewound heatsinkable resistors affording a very low profile, and superior thermal transfer characteristics when compared to conventional aluminum housed wirewound resistors. Close mounting of heat sensitive components is possible due to only a slight rise of the temperature on the aluminum profile. No heat sink compound is required because of large mounting surface. SPECIFICATIONS Power rating: 90W-330W Resistance tolerance: ±5%, ±10% Temperature Coefficients: Normal: 50ppm - 150ppm Low ohmic values: 400ppm Dielectric strength: 2500 VAC peak Working voltage: 1200 VAC Test voltage: 6000 VAC Lead wire: (wire terminal version only): XLPE, 600V, 125C, 18 AWG stranded Insulation: Silicone Rubber & Mica. The Silicone is ULrecognised (UL 94 HB) to a working temperature of 220°C. Temperatures of up to 300°C can be endured for shorter periods. This may however cause an expansion of the silicone rubber with a possibility of reducing the dielectric strength. FEATURES • Solder, wire and “Fast-On” Termination • More resistors in one profile possible • Custom wire lengths available B A 10 300 ø2.2 4.8 POWER DISSIPATION 350 300 W/Resistor 0.6 6 250 200 150 100 WFH330 WFH230 WFH160 WFH90 Lug terminal Power Rating* (watts) 90 160 230 330 Resistance Range (Ω) 0.22Ω – 6.8K 0.47Ω-18K 0.82Ω-27K 1Ω - 39K Wire terminal 50 0 Type WFH90 WFH160 WFH230 WFH330 Dimension (mm) A B L 70 39.7 53 140 80 123 210 2x 80 193 280 2x 100 263 80° 100° 120° 140° Heat Sink Temperature, °C This graph shows the maximum wattage rating for each possible resistor of standard size corresponding to the heat sink temperature. It is assumed that all resistors are equally loaded. 40° 60° THERMAL RESISTANCES Thermal Resistance (°C/W) between different measuring points RTH1 RTH2 RTH3 RTH4 WFH90 WFH160 WFH230 WFH330 2 1 0.75 0.5 6.8 3.9 2.75 2 0.1 0.05 0.03 0.02 0.3 0.17 0.1 0.085 resistor surface to heat sink *at 40°C base plate temperature RTH4 aluminum housing to air RTH2 DESIGNING The following equations are applied in the dimensioning of the resistors at stationary load. If more information is required please consult Ohmite. It is assumed that the air around the resistors is stationary (worst case). See ohmite.com for more examples. 1. WFH is mounted on a heat sink: A. The thermal resistance RTH of the heat sink is known, T = WMAX x (RTH4 + RTH) Check that: TMAX = WMAX x (RTH + RTH3 + RTH1) + TAMB