On Thu, 02 Jul 2009 09:47:54 -0500, the infamous Don Foreman
scrawled the following:

On Wed, 1 Jul 2009 20:20:10 -0400, "Buerste" wrote:

I have some air circuits that are controlled by cams that actuate manual air
valves that look like limit switches with roller arms that follow the cam.
Would I be better off with electric limit switches on the cams and use
electric air valves? The cam rotates at 120 rpm. The dwell on the switch
is 45 degrees.

I do have to replace the air switches every 2 years or so.

One difference between the approaches is that the cams operate the
mechanical switches gradually compared to switches and electric air
valves, so changing to electric might introduce some "hammer" when
they abruptly open and/or close. The difference may also affect
system timing, but once set up right it would tend to survive repairs
involving replacement of switches and/or valves.

I've seen air-damped solenoids, so I know they're available in at
least some form factors, FWIW.
Only the curious will learn and only the resolute overcome
the obstacles to learning. The quest quotient has always
excited me more than the intelligence quotient.
-- Eugene S. Wilson