Metalohm Series FEATURES * Flameproof and inorganic * Higher power rating due to heat sink capacity * All welded construction * Nonhygroscopic * High surge construction Wirewound Resistors term. style 277 SPECIFICATIONS Electrical Wattage: Based on a 275C "U" characteristic derating curve Temperature coefficient: 18 ohm: 0 90ppm/C 8 < 18 ohm: 0 50ppm/C <8 ohm: 0 180ppm/C (TC for some watt/ohm combinations may be lower) Dielectric strength: Terminal to case, depends on terminal style (1500V min.) Creepage: term. style 277: 1.2" term. styles 278/276: 0.4"/0.7" term. styles 211/252/279: 0.15" Termination Wires * Stranded, available in any insulation rated 125C or higher (may require term. style 297). * Custom cut/stripped lengths * Can be potted or pre-soldered to terminal styles 211 or 252 * Quick connect (fully or partially insulated), ring or spade terminations available Dielectric Sleeves * Steatite construction * Style 276 meets UL/NEMA 2500V RMS for one minute requirement * Available as terminal styles 276, 277, 278, 297 0.250" term. style 276 (sq. collar, G3923) 278 (oval collar, G3860) o0.195" C B A o0.068" 0.005 term. style 279 23/16" 1.5" max. max. 1.5" max. term. style 252 0.5" D o0.089" 0.75" 5/16" term. style 211 o0.171" 1" max. term. style 297 0.437" dia. wire 1.25" max. term. style 298 wire 1.25" max. Watts Style w/o heat sink w/ heat sink* 20/45M 20 45 40/70M 40 70 HV40-70M 40 70 50/100M 50 100 60/115M 60 115 Dimensions (inches) A B C 1 17/16 17/8 29/16 3 37/16 9 2 /16 3 37/16 311/16 41/8 49/16 59/16 6 67/16 D 3/4 3/4 7/8 3/4 3/4 Ohmic range** 0.05-6K 1.0-25K 1.0-25K 1.5-47.5K 2.5-81K *Based on a 12"x12"x1/8" aluminum heat sink, using a thermal compound, in a 25C ambient **Standard winding ranges only listed, other values available; contact factory. OPTIONS DIELECTRIC STRENGTH * Noninductive versions (ArytonPerry windings) * Terminal sleeves to increase dielectric strength and maximize creepage distance * Variety of terminal choices * Potted or soldered wire leads including quick connect, ring, spade terminals * Tapped models Terminal Type 211 Style 20/45M 1500 40/70M 1500 HV40/70M N/A 50/100M 1500 60/115M 1500 252, 279 N/A 1500 N/A 1500 1500 276 278 277 Dielectric Strength N/A N/A N/A 2500 2500 N/A N/A N/A 4250 2500 2500 N/A 2500 2500 N/A 297 298 2500V 2500V N/A 2500V 2500V 2500V 2500V N/A 2500V 2500V O R D E R I N G I N F O R M AT I O N Style Non-inductive Tolerance Ohms 1R000 = 1.000 (optional) K = 10% 10R5K = 10,500 J = 5% H = 3% G = 2% F = 1% Terminal Type (see diagram) Ohmite Mfg. Co. 1600 Golf Rd., Suite 850, Rolling Meadows, IL 60008 * Tel. 1-866-9-OHMITE * Fax 1-847-574-7522 * www.ohmite.com * info@ohmite.com 27