So I just aquired a vacuum pump from a friend... on loan
It's a rotary vane type pump that will pull 20"Hg or 25"Hg intermittently.
So, I don't want to fry this pump while vacuum bagging. Therefore, I need a vacuum limit switch. Having very little budget to do this, I'm posting this question to everyone. Any solutions?
Here's the one I came up with... And I do recognize the Rube Goldbergian properties of it. Hook up a syringe to the vacuum lines and on the plunger, hang a weight. Below the weight, place a micro switch. When there's vacuum, the weight hangs above the switch and the pump is off. If the system loses vacuum, the weight falls the switch is closed. This will cost me about $5 (10 cents for syringe and ~$4 for switch), $10 at the most including electrical components.
Diagram
Thoughts, suggestions, alternatives? Anything blatantly obvious I'm missing?