sales and corporate of?ce 1717 chicago avenue riverside, california 92507-2364 phone: (951) 788-1700 fax: (951) 369-1151 applications engineering 17271 north umpqua hwy. roseburg, oregon 97470-9422 phone: (541) 496-0700 fax: (541) 496-0408 e-mail: caddock@caddock.com ? web: www.caddock.com for caddock distributors listed by country see caddock.com/contact/dist.html ? 2004 caddock electronics, inc. ca d k do c MP312 and mp330 power film resistors type mp chassis mounted power film resistors are made with micronox ? resistance ?lms ?red onto a ceramic substrate which is thermally bonded to an anodized aluminum base. by mounting this assembly directly to a metal surface for improved heat transfer, the high power capabilities of these unique resistors can provide increased packaging densities in many types of electronic equipment. the special performance features of these type mp chassis mounted power film resistors include: ? two case sizes that provide 15 watt and 30 watt ratings. ? operation up to 275c. ? single screw mounting to simplify attachment to the chassis or other heat conducting surface. ? a molded silicone case that encapsulates the resistor assembly to meet stringent environmental speci?cations. ? extended life stability better than 0.01% per 1,000 hours has been demonstrated through a 5 1 / 2 year, 50,000 hour program of continuous load life testing. speci?cations: resistance tolerance: 1% (other tolerances on special order). insulation resistance: 10,000 megohms min. terminal strength: mil-std-202, method 211, cond. a (pull test) 5 lbs., and cond. b (bend test), r 0.2% max. or 0.2 ohm max., whichever is greater. thermal shock: mil-r-39009, r 0.5% max. or 0.2 ohm max., whichever is greater. momentary overload: 2 times rated power with applied voltage not to exceed 1.5 times maximum continuous operating voltage for 5 seconds, r 0.5% max. or 0.2 ohm max., whichever is greater. moisture resistance: mil-std-202, method 106, r 0.5% max. or 0.2 ohm max., whichever is greater. load life: mil-r-39009, 1,000 hours at rated power, r 1% max. or 0.2 ohm max., whichever is greater. power rating dependent upon chassis area. see power rating graphs. shock, medium impact: 50g, mil-std-202, method 205, cond. c. vibration, high frequency: mil-std-202, method 204, cond. b, r 0.2% max. or 0.2 ohm max., whichever is greater, through shock and vibration sequence. terminals: gold plated solder lugs. chassis mounted precision power film resistors with center screw mounting stacked type mp power film resistor assemblies stacked type mp assemblies - constructed by bolting resistors between aluminum heat dissipating plates - provide a simple means of further improving packaging densities. these charts of power ratings versus air ?ow and chassis area show the high power levels that can be achieved with forced air cooling and with convection cooling in either vertical or horizontal orientation. air flow (cfm)/each resist or 10 4 2 0 .2 .3 .4 wa tts/each resist or .7 1 2 3 4 7 10 20 30 6 8 12 14 16 18 for st acked mp 312 power resist ors convection cooling - pla tes in horizont al plane convection cooling - pla tes in ver tical plane data is for 25 c air at 1 atmosphere, ducted around resistors in the stack with 2" x 2" x .04" aluminum plates between resistors. to derive tota l airflow required for stack, multiply airflow/each resistor by the number of resistors in the stack. ducting is not required when designing fo r convection. chassis area (sq. in.) 15 5 0 2 4 wa tts 6 10 20 40 60 100 10 20 25 30 for chassis mounted single resist ors data is for 2 5 c still air a t 1 atmosphere. chassis material: aluminum, .040" thick. 1 model no. mp 330 model no. mp 312 power rating power rating c caddock 100 1% mp 312 15 w 40 3 d - hole for mountin g b 2 b a aluminum base dimensions in inches and (millimeters) .188 (4.78) dielect . strength wa tt- age ? model no. c dimensions in inches and (millimeters) resistance min. mp 312 .185 (4.70) 15 600 50 10 ? 200 k high t emp tc ?? max. max. vo ltag e 300 b a .600 (15.24) .250 (6.35) .250 (6.35) .850 (21.59) mp 330 30 1,000 50 10 ? 200 k 450 .142 (3.61) .092 (2.34) d ?? tc: 50 ppm/c referenced to +25c, r taken at +150c and +275c. (low temp. tc will be nominally -85 ppm/c at -55c. see typical r-t curve.) ? MP312 15 watt power rating based on chassis mounting on a 6" x 4" x 2" x .040" aluminum chassis, MP312 free air rating is 2.5 watts at 25c. mp330 30 watt power rating based on chassis mounting on a 7"x 5" x 2" x .040" aluminum chassis, mp330 free air rating is 5.0 watts at 25c. ambient tempera ture, c 100 80 60 40 20 0 25 75 125 175 225 275 ra ted load, % tempera ture, c 2 1 0 -1 0 5 0 100 150 200 % ? r -55 250 typical r-t curve derating curve 28_il123.1004
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