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.

Why don't you replace the cams with discs with
notches (the existing cams might actually still
work) and use optical sensors to sense the up/down
of the cam?
This will have no wear at all except the shaft
bearings of the cam. The sensors can then drive a
single transistor to control DC solenoid valves.
Some of the better valves can operate for millions
of cycles. And, if they wear out, you don't have
to adjust the cam timing when you replace them. I
have salvaged sensors from old floppy drives and
used them for a bunch of projects.

Jon