Overheating of flexible tinned copper connectors

Overheating of flexible tinned copper connectors has been observed at a num ber of power stations. These connectors are used to connect the generator t o outgoing busbars and transformers thus serving to counter the effects of vibration and thermal expansion forces. It is shown that the main cause for the observed overheating is a result of a combined action of the high init ial contact resistance, fretting, stress relaxation, differential thermal e xpansion and the formation of intermetallics at the copper-tin interfaces.