250 Series • All-welded construction. • RoHS compliant product available. Add “E” suffix to part number to specify. ‘Thin’ Stackohm® Vitreous Enamel Power �������� 0.031" 0.794 mm Diam. 0.063" 1.588 mm Diam. 0.125" 3.175 mm 0.110": 2.776 mm 0.125" 3.175 mm 0.625" 15.875 mm 0.375" 9.525 mm 10W & 20W L A 0.125" * 3.175 mm 0.375" 9.525 mm 0.250" 6.350 mm 0.125" 3.175 mm Diam. 0.109" 2.776 mm Diam. 0.196" 4.979 mm 0.250" 6.350 mm 0.188" 4.763 mm 30W, 40W & 55W L A 1.000" 25.400 mm Material Coating: Lead free vitreous enamel. Core: Ceramic. Terminals: Tinned lug with hole. RoHS solder composition is 96% Sn, 3.5% Ag, 0.5% Cu Derating: Linearly from 100% @ +25°C to 0% @ +350°C. Electrical Tolerance: ±5% (J) Power rating: Based on mounting a single resistor on a metal surface measuring 10” (254mm) square by 0.04” (1.016mm) F eat u r es thick. Reduce rating by 15% when mounting on non-metallic • Small size-to-power ratio. surface. • Stackable Overload: 10x rated wattage for • Integral mounting bracket con5 seconds if max. voltage is not ducts heat to mounting surface. exceeded. • Low profile for use in equipment Temperature coefficient: where space is limited. 1 to 20Ω: ±400 ppm/°C. Over 20Ω: ±260 ppm/°C ordering infO Dielectric withstanding Series RoHS Compliant voltage: 500 VAC: 10 and 20 watt rating. 1000 VAC: 30, 40 and 55 watt rating (measured from lug to Coating Wattage Tolerance Ohms Blank = Vitreous F = 1% 1R0 = 1 Ω mounting bracket) C = Centohm H = 3% 250 = 250 Ω To calculate max. amps: S = Silicone J = 5% 1K0 = 1,000 Ω K = 10% 25K = 25,000 Ω use the formula √P/R 0.375" 9.525 mm S pe c i f i c at i ons 0.938" 23.813 mm When limited space is a consideration, choose Ohmite’s “thin” stackable 250 Type resistors. These oval-shaped ceramic-core resistors feature a low profile to permit installation in spaces with height restrictions. They are also equipped with integral mounting brackets so they can be fastened to a chassis and stacked in locations with limited surface area. When properly fastened, the mounting brackets add a heat sinking benefit resulting in a smaller size per watt. Durable 250 Type resistors are fully welded and coated with lead free vitreous enamel. 0.250" * 6.350 mm 0.125" 3.175 mm 0.438" 11.113 mm *Reference dimension only; varies according to resistance value. Note: When resistors are stacked, use washers or spacers as required to insure clearance and improve power dissipation. 25K5 = 25,500 Ω Made-to-order parts Terminal Type See website for See “Resistor Terminals for Tubular Cores” custom core info Tolerance RoHS Compliant J = 5% ��������������� Series Vitreous enamel: 25 = 250 Fixed 26 = 260 Adjustable Silicone ceramic: 45 = 450 Fixed 46 = 460 Adjustable Wattage & Core Code See “Core and Terminal Selection” Mounting Brackets (user supplies bracket for core TB) B = Stacking box S = Stacking stud, std. height H = Stacking stud high U = Unit type Ohms Example: 1R00 = 1 Ω 250R = 250 Ω 1K00 = 1,000 Ω 25K0 = 25,000 Ω 25K5 = 25,500 Ω Dimensions (in. /mm) Max. Length L Length A Voltage* 0.750 / 19.050 1.000 / 25.400 187 2.000 / 50.800 2.313 / 58.750 815 1.250 / 31.750 2.000 / 50.800 281 2.000 / 50.800 2.750 / 69.850 655 3.500 / 88.900 4.250 / 107.950 1405 Series Wattage Ohms F10 10 1.0-15K F20 20 1.0-50K F30 30 1.0-10K F40 40 1.0-25K F55 55 1.0-30K Adjustable versions available. Consult Ohmite. Other sizes available. Consult Ohmite. Also available in low cost Centohm or Silicone coating. Consult Ohmite. * Maximum Voltage is based on Ohm’s Law [V=√P*R] as limited by the resistance value of specified product S ta n d a r d pa rt n u m b e r s f o r 2 5 0 s e r i e s 1,500 2,000 2,500 3,000 4,000 5,000 6,000 7,500 10,000 15,000 20,000 25,000 40,000 –––1K5E –––2K0E –––2K5E –––3K0E –––4K0E –––5K0E –––6K0E –––7K5E –––10KE –––15KE –––20KE –––25KE –––40KE F55J––– 55 F40J––– 40 F30J––– 30 F20J––– 20 –––50RE –––75RE –––100E –––150E –––200E –––250E –––300E –––400E –––500E –––750E –––800E –––1K0E –––1K25E Part No. Prefix Suffix F10J––– 10 50 75 100 150 200 250 300 400 500 750 800 1,000 1,250 Ohmic value Ohmic value F55J––– 55 F55J––– 55 F40J––– 40 F40J––– 40 F30J––– 30 F30J––– 30 F20J––– 20 F20J––– 20 F10J––– 10 F10J––– 10 –––1R0E –––1R5E –––2R0E –––3R0E –––4R0E –––5R0E –––7R5E –––10RE –––15RE –––20RE –––25RE –––30RE –––40RE Part No. Prefix Suffix Wattage 1 1.5 2 3 4 5 7.5 10 15 20 25 30 40 Wattage Part No. Prefix Suffix Ohmic value Wattage = Standard values; check availability using the worldwide inventory search at www.ohmite.com Ohmite Mfg. Co. 1600 Golf Rd., Rolling Meadows, IL 60008 • 1-866-9-OHMITE • Int’l 1-847-258-0300 • Fax 1-847-574-7522 • www.ohmite.com • [email protected] 33