Barcelona 12 15 May 2003 EVALUATION OF HIGHTEMPERATURE
Barcelona 12 -15 May 2003 EVALUATION OF HIGH-TEMPERATURE FLUORINATED ETHERS (PFPE) FOR POWER CONNECTORS OPERATING AT EXTREME SERVICE CONDITIONS Barry JOHNSON and Dmitry LADIN Tyco Electronics – Canada bjohnson@tycoelectronics. com Milenko BRAUNOVIC MB Interface - Canada, mbinterface@yahoo. com JOHNSON_CA_author_ALPHA 1_BLOCK 1
Barcelona 12 -15 May 2003 Competitive Industry • • • From system growth to prolonging the operating life Increased energy consumption in densely populated areas Transmission/Distribution lines carry greater loads Operating temperature of conductors raised beyond 1300 C New type of high temperature conductor (ACSS) Stability of power connections at extreme operating conditions JOHNSON_CA_author_ALPHA 1_BLOCK 1
Barcelona 12 -15 May 2003 Lubrication of Power Connections • • • Contact aid compounds commonly used for Al and Cu Contact zone protection Low thermal stability of currently used compounds Inertness and low viscosity of fluorinated ethers PFPE-based lubricants can sustain operating temperatures as high as 2000 C JOHNSON_CA_author_ALPHA 1_BLOCK 1
Barcelona 12 -15 May 2003 Lubricants Selection • Maximum operating temperature range • Formulation: base oil and additives • Thickeners: – not melting – improved adhesion to the substrate – lower wear rates JOHNSON_CA_author_ALPHA 1_BLOCK 1
Barcelona 12 -15 May 2003 UV Resistance • Per ASTM G-53 -95 and ASTM D-638 -95 • Accelerated Weathering Tester: cycles of 4 hrs UVB at 600 C, followed by 4 hrs of condensation at 500 C • Lubricant failed: no longer can be spread and/or has severe cracking JOHNSON_CA_author_ALPHA 1_BLOCK 1
Barcelona 12 -15 May 2003 WEATHERING TESTER JOHNSON_CA_author_ALPHA 1_BLOCK 1
Barcelona 12 -15 May 2003 Long-Term Temperature Exposure • Forced Air Oven set to 2000 C • Exposure time: more than 2000 hrs • Material Examination: – Discoloration – Cracking – Hardening JOHNSON_CA_author_ALPHA 1_BLOCK 1
Barcelona 12 -15 May 2003 Appearance of the Lubricants (Thermal Ageing) PASSED FAILED BEFORE EXPOSURE JOHNSON_CA_author_ALPHA 1_BLOCK 1 AFTER EXPOSURE
Barcelona 12 -15 May 2003 Thermogravimetric Analysis (TGA) • • Determination of thermal stability Weight change measurement Heating rate: 10 0 C/min N 3 is stable up to 4000 C JOHNSON_CA_author_ALPHA 1_BLOCK 1
Barcelona 12 -15 May 2003 Current Cycling Tests • Test I: measured contact resistance and temperature of lubricated Al-to-Al busbar bolted joints: – Thin layer of the lubricant spread overlapping zones – Joints repeatedly heated up to 2000 C (for 5 min) and cooled to ambient temperature JOHNSON_CA_author_ALPHA 1_BLOCK 1
Barcelona 12 -15 May 2003 Current Cycling Tests • Test II: wedge connectors assembled with 336. 4 kcmil ACSS conductors: – Followed modified ANSI 119. 4 Class AA procedure – Temperature of the control conductor was raised to 2000 C JOHNSON_CA_author_ALPHA 1_BLOCK 1
Barcelona 12 -15 May 2003 µ µ Results of the Current Cycling Tests • • Typical data sample: lubricated Al to Al wedge connectors N 3 and C 1 lubricants are the base formulation for effective high temperature applications JOHNSON_CA_author_ALPHA 1_BLOCK 1
Barcelona 12 -15 May 2003 Discussion & Conclusions • Two PFPE lubricants with sufficient UV and thermal ageing stability are identified • The lubricants were effectively utilized as contact-aid compounds in current cycling tests • Results obtained under controlled laboratory conditions • Suggested materials should be subjected to the field service conditions • Necessary fillers and metallic additions are to be incorporated to make HT contact-aid compounds JOHNSON_CA_author_ALPHA 1_BLOCK 1
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