They would pass a lot more current and do not arc.
They were required to be in the operating position for some time
unless they have heaters.

Martin

On 1/17/2014 9:38 PM, Jon Elson wrote:
Ignoramus23003 wrote:


Paul, I believe that this is what these switches are for, for very
frequent switching.
Really old DEC computers used them. I guess the problem was the
possibility of the turn-on surge welding the contacts of traditional
contactors, and the mercury contactors were pretty immune to
that. This was in the PDP-8 days of the 1960's.

Jon