Resistors Ultra Low Profile Power Resistors WDBR-UL Series Ultra low profile thick-film on steel Up to 7kW peak power Single fixing heatsink mountable Ideal for dynamic braking, inrush limit and snubber circuits Choice of flying lead or solder terminations Low inductance design High isolation, even aer fft ailsafe overload fusing RoHS compliant, non-flammable construction UL508 certified - UL file E238661 All All Pb-Pb-frfreeee parts c parts comply omply with EU Dirwith EU Directivective e 2011/65/EU amended b2011/65/EU amended by y (EU) 2015/863 (R(EU) 2015/863 (RoHS3)oHS3) Electrical Data WDBR1UL WDBR2UL WDBR3UL WDBR5UL WDBR7UL 5 Resistance range ohms 12, 15, 20, 22, 25, 47, 50, 100, 150 Resistance tolerance % 10 1 Pulse power rating kW 1.5 2.0 3.5 5.0 7.0 2 Power rating on heatsink W 170 190 240 250 260 3 Power rating on fan-cooled heatsink W 660 740 850 950 1410 TCR ppm/C < +600 Maximum element temperature C 450 Ambient temperature range (heatsink) C -55 to +200 4 Dielectric withstand V (dc/ac peak) 2500 Inductance (typical) H <3 <4 <5 <6 Notes: 1. For details of pulse condition see Fig. 1 in Performance Data. 2. Mounted on a 0.53C/W heatsink with no forced air cooling, air temperature 25C. 3. Mounted on a 0.53C/W heatsink with 5m/s forced air cooling, air temperature 25C. 4. Based on 100% production test, duration 2s minimum 5. Other ohmic values upon request Physical Data Dimensions in mm, weight without terminations in g Fixing hole is located centrally. L W t D Wt. a 1 b 1 c 1 0.25 0.25 0.1 nom nom WDBR1UL 49.3 35.9 3.2 4.2 17.6 4.2 12.6 WDBR2UL 61 40.6 0.9 5.5 19.7 5.5 17.1 WDBR3UL 101.6 70 14.5 24.8 10.1 50.8 5.3 WDBR5UL 122 70 15.3 27 8.6 101.2 1.5 WDBR7UL 152.4 101.6 39.3 10.7 11.8 181.8 Construction A high integrity dielectric layer is applied to a machined stainless steel substrate. Thick-film conductor and resistor paerns artt e printed and fired, then protected with a high temperature overglaze. The termination pads are tinned with solder and optional leads are soldered on. General Note BI Technologies IRC Welwyn TT Electronics reserves the right to make changes in product specification without notice or liability. All information is subject to TT Electronics own data and is considered accurate at time of going to print. www.ttelectronics.com/resistors TT Electronics plc 10.19Ultra Low Profile Power Resistors WDBR-UL Series Terminations The following termination options are available Option Code Nominal Dimensions (mm) PL WDBR-UL Size 1 & 2 3 5 & 7 1 Solder pad only I Pad Length, PL 8.8 8.1 9.1 PW Pad Width, PW 5 8.1 6.1 250mm Flying leads, 3mm UL3134/5, 40A, L 600V Notes: 1. Two options exist for solder type. The standard is SnAg (96SC) which is Pb-free and the second (HT) is high temperature HMP alloy which is Pb-bearing. Both are RoHS compliant, but the second relies on the RoHS exemption for high temperature solders and is targeted at specialist high temperature applications. Thermal Performance Maximum Pulsed load at full pulse power rating 50,000 cycles (see Fig 1) 5 R% Mounted on a 0.53C/W heatsink with 5m/s forced air cooling, air temperature 25C. Derating at heatsink temperatures >160C See Fig. 2 Fig.2: TemperatureDerating Fig. 1: Duty CycleWaveform 120 1ms 100 Ppk 80 60 40 20 0 8s 1ms 050100 150200 250 2s Heatsink Temperature(C) General Note BI Technologies IRC Welwyn TT Electronics reserves the right to make changes in product specification without notice or liability. All information is subject to TT Electronics own data and is considered accurate at time of going to print. www.ttelectronics.com/resistors TT Electronics plc 10.19 % of Rated Power