Metal finishing Q&As since 1989
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"Hot" wires cause electrical erosion wear
Q. We have a situation with wires whizzing and sliding over steel pulleys with fairly high currents flowing thru the wires. We want to reduce the "wear" caused by the arcing and slipping. Tests indicate the "wear" is more a spark erosion process. We want to identify a material we can plate (or otherwise deposit) onto the pulleys that will boost electrical conductivity thereby improving wear life. All suggestions gratefully appreciated.
Jim IrwinMaterials Processing - Austin, Texas
2004
A. So far, it sounds like a mechanical problem. Keep the wire in contact with the pulley and keep them clean.
An idler holding the wire in contact with the pulleys is a possibility; or an idler set up so the wire wraps around the pulley; or 2 pulleys set up for significant wrap around each and electrically connected.
As for cleaning, application-specific, and you haven't told us the application or its environment or what you consider a 'fairly high current' or the contact area between the wire and pulley or...?
Tom Gallant- Long Beach, California, USA
2004
A. It is not clear to me precisely what is happening in your application, but it may be useful to try a cryogenic treatment of the wires and / or pulley. Without knowing the materials (metals) involved, it's difficult to know if it would be a good candidate or not. We have seen improved conductivity and better thermal transfer in a variety of materials (after treatment) as well a reduced coefficent of friction. Certain steels (e.g. high carbon) also show dramatic improvement in wear resistance. It's worth discussing with a knowledgable party that has experience in cryogenic treatment of metals.
Robin RhodesWorcester, Massachusetts
2004
A. If I understand the problem correctly, there is a significant voltage on the wires causing arcing. One simpler way could be electrically isolating the pulleys from ground so the wires are not grounded through the pulleys. Could you use non-metal shafts, even wood-shafts, for pulleys?
Mandar Sunthankar- Fort Collins, Colorado
2004
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