On Jul 2, 5:26*am, "Buerste" wrote:
"Jon Elson" wrote in message

...



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

WAY dusty atmosphere and I don't want to complicate a simple function. *A
mechanic can replace an air switch in 5 minutes. *The time to troubleshoot
anything more complex would cost $7/min in lost production.

There is your answer.

Stay with air.

Check the quality of the air switch...there are different levels of
quality=number of activations.

You may get the desired result by using a better air switch.

TMT