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  for Metal Finishing since 1989
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Difference between using Phosphor Bronze and ETP copper as moving contact in a switch

I am Dip Malhar mechanical engineer from Bangalore, working on a project related to switch. I wanted to understand difference between using phosphor bronze and ETP copper as moving contact material. I hope this must help in reducing the temperature rise.

Dip Shah
Student - Bangalore, Karnataka, India
2006

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The resistance of a switch contact depends on a number of variables but principally the force on the contact. Copper is soft so any unsupported contact is usually made of phosphor bronze or beryllium copper. This also eliminates the need for a separate spring. Copper alloys corrode so, depending on the atmosphere and the contact area, contact pressure, sliding or pressure contact design etc. the contact area is either plated or has an inserted contact point. This will be silver, gold or a number of alloys. With good contact design there is minimal resistance and therefore no heat loss

Geoff Smith
Hampshire, England
2007