Think in terms of PRESSURE! I learned a lot about this topic years ago when I analysed catastrophic failures on relays and connectors. Railway connector makers know all about high current contacts, they need connectors for 10,000 amperes! Pressure and correct sliding mechanism is alfa & omega. Oftenly, they use copper alloyed pins without any kind of plating. When the pin and the female meets, the sliding force removes all debris and when the mating is fulfilled, the resulting pressure per microscopic contact spot is so high that you have an almost gastight connection. This is the secret of a successful high power connector. 80A does not seem much, but you still ought to consider basics.
Below is a good example on what I mean. These connectors have a spring loaded ring that cause hundreds of reliable high pressure microcontacts on the pin.
http://www.multi-contact-usa.com/products/powerline/1
Good Luck
Ingemar Hernefjord
Ericsson Microwave Systems
PS. Carbon steel pin, not much used as pin bulk material...
-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of - Bogert
Sent: den 11 februari 2005 00:39
To: [log in to unmask]
Subject: [TN] Calculate current capacity for electrical contacts
February 10, 2005
How does one determine what current can be carried by electrical connector contacts to determine capability to carry about 80 AMPs (RMS), low freq AC, or DC.
We have an application that uses a carbon steel base metal pin contact. The contact is given a nickel flash, followed by a copper plating (to fill in small voids), followed by another nickel flash, followed by silver plating. Does one calculate current capacity from just the carbon steel base metal, or does one need to take the plating into account? What formula or chart is used to support the calculation? If the nickel flash thickness is increased, will it impact current capacity? If plating is changed to gold, does that impact current
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capacity?
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