ultra low profle power resistors wdbr series www.bitechnologies.com www.irctt.com www.welwyn-tt.com general note tt electronics reserves the right to make changes in product specifcation without notice or liability. all information is subject to tt electronics own data and is considered accurate at time of going to print. ? tt electronics plc 2.14 ultra low profle thick-flm on steel 500w to 7kw peak power single fxing heatsink mountable ideal for dynamic braking, inrush limit and snubber circuits choice of fying lead, push-on or solder terminations low inductance design high isolation, even after failsafe overload fusing rohs compliant, non-fammable construction wdbr1/2 wdbr1 wdbr2 wdbr3 WDBR5 wdbr7 resistance range ohms 12, 15, 20, 22, 25, 47, 50, 100 12, 15, 20, 22, 25, 47, 50, 100, 150 resistance tolerance % 10 pulse power rating 1 kw 0.5 1.5 2.0 3.5 5.0 7.0 power rating on heatsink 2 w 160 180 200 260 270 280 power rating on fan-cooled heatsink 3 w 300 700 780 900 1000 1490 tcr ppm/c +500 to +600 maximum element temperature c 365 ambient temperature range (heatsink) c -55 to +200 dielectric withstand 4 v (dc/ac peak) 2500 inductance (typical) h <3 <4 <5 <6 physical data electrical data dimensions in mm, weight without terminations in g l 0.1 w 0.1 t 0.1 ?d nom a nom b nom c nom wt. nom wdbr1/2 31.9 28.1 0.9 2.2 7.5 3.1 4.3 6.5 wdbr1 49.3 35.9 3.2 3.2 11.2 6.2 12.6 wdbr2 61 40.6 5.3 4.7 13.0 5.8 17.1 wdbr3 101.6 70 13.5 22.0 10.2 50.8 WDBR5 122 70 14.0 23.8 7.4 60.7 wdbr7 152.4 101.6 1.5 15.0 51.3 9.2 181.8 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 construction a high integrity dielectric layer is applied to a machined stainless steel substrate. thick-flm conductor and resistor patterns are printed and fred, then protected with a high temperature overglaze. the termination pads are tinned with solder and optional terminals or leads are soldered on. fixing hole is located centrally except on wdbr1/2 where the dimension from the edge by the terminations to the mounting hole centre is 16.68mm w l c b a substr at et hickne ss =t d
ultra low profle power resistors wdbr series www.bitechnologies.com www.irctt.com www.welwyn-tt.com general note tt electronics reserves the right to make changes in product specifcation without notice or liability. all information is subject to tt electronics own data and is considered accurate at time of going to print. ? tt electronics plc 2.14 250m m 3m m terminations the following termination options are available maximum pulsed load at full pulse power rating 50,000 cycles (see fig 1) mounted on a 0.53c/w heatsink with 5m/s forced air cooling, air temperature 25c. r% 5 derating at heatsink temperatures >160c see fig. 2 thermal performance 1m s 1m s 8s pp k 2s fi g. 1: du ty cy cl ew av ef or m 0 20 40 60 80 10 0 12 0 05 01 00 15 02 00 25 0 he at si nk te mp er at ur e( c ) % o f r a t e d p o we r fig .2 : te mp erat ur ed erat in g pl wdbr size ? 1, 2, 3, 5 & 7 pad length, pl 7.5 9.0 pad width, pw 4.5 9.0 wdbr size ? 1, 2, 3, 5 & 7 terminal height, th 6.8 11 terminal width, tw 2.8 6.3 terminal thickness, tt 0.8 0.8 pw 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. th tw tt option code nominal dimensions (mm) solder pad only 1 i flying leads ul3134/5 40a, 600v l push-on connectors t
ultra low profle power resistors wdbr series www.bitechnologies.com www.irctt.com www.welwyn-tt.com general note tt electronics reserves the right to make changes in product specifcation without notice or liability. all information is subject to tt electronics own data and is considered accurate at time of going to print. ? tt electronics plc 2.14 wdbr resistors may be customised in various ways including: alternative shapes and dimensions up to 406mm x 406mm integration of temperature measurement elements alternative ohmic values, tolerance & tcr increased dielectric withstand voltage custom braking resistors with ul approval for a full applications note for dynamic braking see http://www.welwyn-tt.com/pdf/application_notes/wdbr.pdf ma xi mu ms in gl e over lo ad po we r 0. 1 1 10 100 0. 01 0. 11 10 100 du ra ti on of ov er lo ad ( s) po we r( kw ) dbr1/ 2 dbr1 db 2 db 3 w db 5 db 7 sing le ov er lo ad ener gy ca pa cit y 0. 01 0. 1 1 10 100 0. 01 0. 11 10 100 dura ti on of ov er lo ad ( s) en er gy (k j) w dbr1/ 2 w dbr1 w db r 2 w db r 3 w db r 5 w db r 7 overload conditions maximum peak current (a) w w w w w w r r r r value (ohms) 12 15 20 22 25 47 50 100 150 wdbr1/2 15.2 15.2 7.6 7.6 7.6 7.6 7.6 7.6 wdbr1 21.6 21.6 21.6 8.3 8.3 8.3 8.3 8.3 8.3 wdbr2 20.3 20.3 7.6 7.6 7.6 7.6 7.6 7.6 7.6 wdbr3 25.4 25.4 25.4 25.4 11.4 11.4 11.4 11.4 11.4 WDBR5 25.4 25.4 25.4 25.4 25.4 10.2 10.2 10.2 10.2 wdbr7 44.5 44.5 44.5 44.5 44.5 20.3 20.3 20.3 20.3 bolt size typical tightening torque (nm) wdbr1/2 m2 0.6 wdbr1 m3 2 wdbr2 m5 2.5 wdbr3 m5 2.5 WDBR5 m5 3.5 wdbr7 m5 4 application notes a heatsink with thermal resistance 0.53c/w will en able the component to operate at its continuous power rating. thermal grease (e.g. dow corning dc340) should be used and the heatsink should have a surface fnish of <6.3m with fatness of <0.05mm. the resistor should be mounted using an appropriate bolt as listed in the table below. this should be tightened so as to bring the whole area of the steel substrate into intimate contact with the heatsink. the unmounted part is slightly bowed so that the centre is above the edges. inadequate tightening will leave the centre out of contact with the heatsink, whilst over tightening can cause the edges to rise. the tightening torque required will depend on the fxings and heatsink used, but typical fgures are given for guidance. wdbr resistors will fail safe (open circuit) under overload fault conditions and still maintain a 1kv dielectric withstand.
ultra low profle power resistors wdbr series www.bitechnologies.com www.irctt.com www.welwyn-tt.com general note tt electronics reserves the right to make changes in product specifcation without notice or liability. all information is subject to tt electronics own data and is considered accurate at time of going to print. ? tt electronics plc 2.14 example: wdbr2 at 100 ohms and 10% tolerance with standard solder , fying leads and packed in a box of 40 pieces: solder option ordering procedure wd br r l w ty pe va lu e( us e ie c62c ode) to le ranc e( us e ie c62c ode) k1 0% te rm in at io n i so ld er pa do nl y lf ly in gl ea ds tp ush- on co nn ec to rs pack in g 96sc standard ht hmp high temperature w wdbr1/2i bulk 180/box standard wdbr1/2t 64/box wdbr1/2l, wdbr1l, wd- br2l, wdbr3i, wdbr3t, WDBR5i, WDBR5t 40/box wdbr1i, wdbr2i 100/box wdbr1t, wdbr2t 80/box wdbr3l, WDBR5l, wdbr7 all terminations 20/box
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