Calibrate Pressure Switch?

[Mr V]

Adjusting or attempting to adjust the switch to a higher pressure is a huge wast of time. If anything you want a switch that shuts of and turns back on at a lower pressure. The compressor will thank you with building up less heat over time and getting it back up to pressure quicker. Take a look at the rated outputs of compressors the lower the pressure it is working against the higher the cfm. Or take a look at your gauge when you fill the system from empty you'll find the rate of increase in stored pressure decreases dramatically as the stored pressure rises.

[FrankJ]

Originally Posted by Mr V

Adjusting or attempting to adjust the switch to a higher pressure is a huge wast of time. If anything you want a switch that shuts of and turns back on at a lower pressure. The compressor will thank you with building up less heat over time and getting it back up to pressure quicker. Take a look at the rated outputs of compressors the lower the pressure it is working against the higher the cfm. Or take a look at your gauge when you fill the system from empty you'll find the rate of increase in stored pressure decreases dramatically as the stored pressure rises.

This discussion got started because the OPs switch was turning off at 105 psi. I am not sure where the point of diminishing returns on your system is, but I would say generally speaking I expect it is more than 105 psi. Our comp bot was good at 110 psi. I think our compressor was on for most of the match so the HP cutoff wasn't that important. If you are running a off robot compressor, there is a big difference between 105 & 120 psi in terms of storage. Compressor efficiency is less of an issue if you are running an off board compressor.

[Mr V]

Originally Posted by FrankJ

This discussion got started because the OPs switch was turning off at 105 psi. I am not sure where the point of diminishing returns on your system is, but I would say generally speaking I expect it is more than 105 psi. Our comp bot was good at 110 psi. I think our compressor was on for most of the match so the HP cutoff wasn't that important. If you are running a off robot compressor, there is a big difference between 105 & 120 psi in terms of storage. Compressor efficiency is less of an issue if you are running an off board compressor.

Yes if you are running an off board compressor that is a different story but with an on-board compressor having it shut off at 105 is perfectly fine and I would say desirable.

[Al Skierkiewicz]

Has anyone actually done the math? How much more storage volume conversion at 60 psi do you get with 110 psi stored in two tanks as opposed to 120 psi? Assume that the regulator is the same efficiency at both pressures, and that the compressor efficiency doesn't matter.

[FrankJ]

Originally Posted by Al Skierkiewicz

Has anyone actually done the math? How much more storage volume conversion at 60 psi do you get with 110 psi stored in two tanks as opposed to 120 psi? Assume that the regulator is the same efficiency at both pressures, and that the compressor efficiency doesn't matter.

In terms of air storage, it is a linear calculation. Essentially ideal gas law, PV=nRT. So saying 60 psi is the minimum useful pressure. 110 PSI gives a delta P of 50. 120 PSI gives a delta P of 60. A 20% difference. That is in the physics lab with no friction, a perfect vacuum & ignoring entropy. All of this will effect how useful the extra air will be.

Life is always more complicated than that. In our case, the minimum useful pressure was 100 psi because that is what it took to consistently shoot the ball. What was important for us was that the compressor turned on before then. 120 psi would have been useful for precharging before the match, but 110 was good for during the match. We also went with minimal on board air storage to keep the recharge time low. So I largely agree with Mr V about what is a good set pressure.