Similar experiences here.The contacts are usually just copper or copper
plated with silver.

Many schemes are contrived to save the wear and tear on the contacts. On
larger capacity units there are two sets of contacts, ones that take the arc
and are easy to replace and a second set that can carry big currents, close
last and open first.

Some use vacuum bottled contacts to eliminate arcing and most use an
inductor or resistance not as good) to afford tap changing without ever
breaking the circuit.

Oh, I have dealt with a few pole mounted units for inline use in the rural
long lines to boost it back up a bit.
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"daestrom" wrote in message ...
The few tap-changers I've seen 'up close and personnel' are in
sub-stations, not pole-mounted. The contacts are in oil-bath and
arranged such that they don't open under appreciable current (multiple
contacts, a center-tapped inductor and ingenious mechanism).

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On 4/19/2011 17:28 PM, Jim Wilkins wrote:
Would the contacts be the tungsten (heavy) cylindrical slugs sometimes
found below equipment-laden power poles?