RPS 500 Vishay Sfernice Power Resistors for Mounting onto a Heatsink Thick Film Technology FEATURES • High power rating • High overload capability • Easy mounting • Low thermal radiation of the case This range has been developed specifically for electrical traction applications and is capable of dissipating 500W at +70°C. The remarkable performance characteristics are evident when used in severe pulse conditions. The copper base allows easy mounting on the heatsink and provides optimal dissipation conditions. DIMENSIONS in millimeters 73 RPS 500D 10.5 56 6 57 26 ± 1 34 35.8 60 Ø 7.2 Ø 21 Ø 4.2 2 M4 USEFUL DEPTH : 8 • Tolerance unless stated: ± 0.2mm MECHANICAL SPECIFICATIONS Mechanical Protection Substrate Insulated case Alumina onto base of nickel coated copper Resistive Element Cermet End Connections Screws M4 (M5 on request) Tightening Torque on Connections 2Nm 4Nm Tightening Torque on Heatsink 250g ± 10% Weight ENVIRONMENTAL Thermal Resistance Temperature Range Climatic Category www.vishay.com 34 ELECTRICAL SPECIFICATIONS Resistance Range Tolerances 0.24 to 1M E24 series ± 1% to ± 10% Power Rating Chassis mounted 500W at 70°C continuous 1000W at 25°C for 10 seconds Temperature Coefficient Standard Limiting Element Voltage Dielectric Strength* ± 300ppm/°C < 1Ω ± 150ppm/°C > 1Ω 5kVRMS L:7kVRMS - H: 12kVRMS Insulation Resistance > 106MΩ Inductance < 50 nH RTH (j-c) 0.11°C/W - 55°C to + 125°C *MIL STD 202, 1 Minute, 10mA Max 55/125/56 For technical questions, contact [email protected] Document Number: 50047 Revision 14-Jan-05 RPS 500 Power Resistors for Mounting onto a Heatsink Thick Film Technology Vishay Sfernice PERFORMANCE TESTS CONDITIONS TYPICAL DRIFTS NF EN 140000 CEI 115_1 2Pn/10 seconds < ± (0.25% + 0.05Ω) NF EN 140000 CEI 68214 Test Na 5 cycles - 55°C to + 125°C < ± (0.25% + 0.05Ω) NF EN 140000 CEI 115_1 1000 hours 500 W/70°C (no cycling) < ± (0.5% + 0.05Ω) MIL STD 202 Method 103 B and D 56 days 95% R.H. < ± (0.5% + 0.05Ω) Momentary Overload Rapid Temperature Change Load Life (chassis mounted) Humidity (steady state) RESISTANCE VALUE IN RELATION TO TOLERANCE AND TCR Ohmic < 1Ω > 1Ω Standard Tolerance ± 5% ± 5% ± 300ppm/°C ± 150ppm/°C Standard T.C.R. Tolerance On Request ± 1% - ± 2% - ± 10% CHOICE OF THE HEATSINK The user must choose the heatsink according to the working conditions of the component (power, room temperature). Maximum working temperature must not exceed 125°C. The dissipated power is simply calculated by the following ratio: (1) ∆T P= [RTH (j-c) + RTH (c-a)] P: expressed in W ∆T: difference between maximum working temperature and room temperature. RTH: (j-c): thermal resistance value measured between resistive layer and outer side of the resistor. It is the thermal resistance of the component: 0.11°C/W. RTH: (c-a): thermal resistance value measured between outer side of the resistor and room temperature. It is the thermal resistance of the heatsink, depending on the heatsink itself (type, shape) and the quality of the fastening device. RECOMMENDATIONS FOR MOUNTING ONTO A HEATSINK Surfaces in contact must be carefully cleaned. The heater must have an acceptable flatness: from 0.05mm to 0.1mm/100mm. Roughness of the heatsink must be around 6.3µm. In order to improve thermal conductivity, surfaces in contact (alumina, heatsink) should be coated with a silicon grease (type SI 340 Rhône-Poulenc or Dow Corning). The fastening of the resistor to the heatsink is under pressure control of two screws. Tightening torque: 4Nm. The following accessories are supplied with each product: 2 off M 4 x 16, 2 off M4 TE 4 x 0.6 and 2 off M4 washers. Document Number: 50047 Revision 14-Jan-04 For technical questions, contact [email protected] www.vishay.com 35 RPS 500 Vishay Sfernice Power Resistors for Mounting onto a Heatsink Thick Film Technology OVERLOADS Short time overload: 2Pn/10 seconds Accidental overload: The values indicated in the graph below are applicable to resistors in air or mounted onto a heatsink. ENERGY CURVE 10000 ENERGY IN JOULES 1000 100 10 1 1.10-7 1.10-6 1.10-5 1.10-4 1.10-3 1.10-2 1.10-1 1 OVERLOAD DURATION IN SECONDS POWER RATING CHART The heatsink temperature should be maintained at the values specified in fig. 2. To optimise the thermal conduction, contacting surfaces should be coated with silicone grease and heatsink mounting screws tightened to 4Nm. 100 % RATED POWER 80 60 40 20 0 0 20 40 60 80 100 120 140 HEATSINK TEMPERATURE IN DEGREES CELSIUS MARKING Series, style, ohmic value (in ), tolerance (in ), tolerance (in %), manufacturing date, VISHAY trade mark. ORDERING INFORMATION RPS 500D H 100Ω ± 10% xxx MODEL STYLE CONNECTIONS RESISTANCE VALUE TOLERANCE CUSTOM DESIGN Optional ± 1% ± 2% ± 5% ± 10% Options on request T.C.R., shape, etc. Optional H: dielectric strength 12kV L: dielectric strength 7kV www.vishay.com 36 For technical questions, contact [email protected] Document Number: 50047 Revision 14-Jan-05 Legal Disclaimer Notice Vishay Notice Specifications of the products displayed herein are subject to change without notice. Vishay Intertechnology, Inc., or anyone on its behalf, assumes no responsibility or liability for any errors or inaccuracies. Information contained herein is intended to provide a product description only. No license, express or implied, by estoppel or otherwise, to any intellectual property rights is granted by this document. Except as provided in Vishay's terms and conditions of sale for such products, Vishay assumes no liability whatsoever, and disclaims any express or implied warranty, relating to sale and/or use of Vishay products including liability or warranties relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright, or other intellectual property right. The products shown herein are not designed for use in medical, life-saving, or life-sustaining applications. Customers using or selling these products for use in such applications do so at their own risk and agree to fully indemnify Vishay for any damages resulting from such improper use or sale. Document Number: 91000 Revision: 08-Apr-05 www.vishay.com 1