Title: EVALUATION OF HIGH-TEMPERATURE FLUORINATED ETHERS (PFPE) FOR POWER CONNECTORS OPERATING AT EXTREME SERVICE CONDITIONS Barry JOHNSON and Dmitry LADIN Tyco Electronics
1EVALUATION OF HIGH-TEMPERATURE FLUORINATED ETHERS
(PFPE) FOR POWER CONNECTORS OPERATING AT EXTREME
SERVICE CONDITIONS Barry JOHNSON and Dmitry
LADIN Tyco Electronics Canada
bjohnson_at_tycoelectronics.com Milenko
BRAUNOVICMB Interface - Canada,mbinterface_at_yahoo
.com
2Competitive 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
1300C - New type of high temperature conductor (ACSS)
- Stability of power connections at extreme
operating conditions
3Lubrication 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 2000C
4Lubricants Selection
- Maximum operating temperature range
- Formulation base oil and additives
- Thickeners
- not melting
- improved adhesion to the substrate
- lower wear rates
5UV Resistance
- Per ASTM G-53-95 and ASTM D-638-95
- Accelerated Weathering Tester cycles of 4 hrs
UVB at 600C, followed by 4 hrs of condensation at
500C - Lubricant failed no longer can be spread and/or
has severe cracking
6WEATHERING TESTER
7Long-Term Temperature Exposure
- Forced Air Oven set to 2000C
- Exposure time more than 2000 hrs
- Material Examination
- Discoloration
- Cracking
- Hardening
8Appearance of the Lubricants (Thermal Ageing)
PASSED FAILED
BEFORE EXPOSURE AFTER EXPOSURE
9Thermogravimetric Analysis (TGA)
- Determination of thermal stability
- Weight change measurement
- Heating rate 10 0C/min
- N3 is stable up to 4000C
10Current Cycling Tests
- Test I measured contact resistance and
temperature of lubricated Al-to-Al busbar bolted
joints - Thin layer of the lubricant spread over
overlapping zones - Joints repeatedly heated up to 2000C (for 5 min)
and cooled to ambient temperature
11Current 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 2000C
12Results of the Current Cycling Tests
µ
µ
- Typical data sample lubricated Al to Al wedge
connectors - N3 and C1 lubricants are the base formulation for
effective high temperature applications
13Discussion 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