Automatic Air Compressor On/Off control idea...

[TheEquineFencer]

OP: Are you concerning that you lose air overnight or while you're not there? What's brand/model/specs on your compressor?

My main concern is me walking out and leaving it on. Then having to hear Linda tell me to go turn the thing off. Some in here have brought up some good points I'm seriously considering. One is adding a valve to cut the air off at the tank when it's not in use. The other is a way to unload the compressor if it is cut off before it completes a cycle and the compressor unloader valve has not unloaded. "Fixing" this problem will probably result in a savings from the motor not starting with a load on it. I can always add a switch to keep if off when I add the automatic controls. Most things in this shop I try to wire to turn themselves off to save on the power bill.

 

[Redlunn]

A papered engineer would probably have everything on it's own stand alone system, with a motion sensor to control the operation and another switch that bypasses the sensor for full on 100% operation all the time. Then add another switching method to give the exact same method of switching that I'm doing now.

This is how an engineer would do it.....
(Not quite done but should be powered up this weekend)
Micro PLC, redundant contactors with fault monitoring, maintenance intervals display, auto moisture drain, etc, etc.

 

[logixjock]

This is how an engineer would do it.....
(Not quite done but should be powered up this weekend)
Micro PLC, redundant contactors with fault monitoring, maintenance intervals display, auto moisture drain, etc, etc.

And I thought that I was Mr. Overkill

 

[TheEquineFencer]

This is how an engineer would do it.....
(Not quite done but should be powered up this weekend)
Micro PLC, redundant contactors with fault monitoring, maintenance intervals display, auto moisture drain, etc, etc.

What brand micro PLC/software did you use? I had a rack of 500's here I was playing with. I almost had the software issue for RSLogix 500 figured out before the shop burned down. My nephew somehow got 500 onto the computer so I could write the programs but we couldn't figure out how to get the computer to communicate with the live rack. All that is gone. One day I hope to get another rack and some software, I guess I'll have to buy the next software. I think PLCs are the neatest things to use for a lot of task. They can make doing a lot of things easy and very flexible when you want to change something. I was planning to use the rack I had for shop automation eventually. There's a website, TheLearningPit.com , they have a free time sensitive download for a training program that mimics RSLogix 500. It a pretty cool program to get you feet wet for learning PLCs. We used it in classes at PCC when I was in the electrical program. I think it's about $40 now.

 

[C96]

Here is another option for you.

This may be the simplest way to achieve your short cycle unloading problem.

Basically, just replace your existing tank check valve with this.

It’s called a Load Genie Combination Unloader & Check Valve

This will automatically unload the head pressure anytime the compressor is shut off for any reason, even a short cycle.

Click on both pictures for more information on each and how to get one.





I think Grainger’s carry them as well

Good Luck

 

[redmondjp]

Here is another option for you.

This may be the simplest way to achieve your short cycle unloading problem.

Basically, just replace your existing tank check valve with this.

It’s called a Load Genie Combination Unloader & Check Valve

This will automatically unload the head pressure anytime the compressor is shut off for any reason, even a short cycle.

Click on both pictures for more information on each and how to get one.





I think Grainger’s carry them as well

Good Luck

That's not a bad idea - my friend's 2HP portable Champion has that exact same valve on it. Basically, it's just a tiny leak on the compressor discharge line upstream of the check valve. I'm not sure what flow this valve is rated for as I've only seen them installed on the smaller compressors.

 

[TheEquineFencer]

I'll have to look into them.
I was looking around that site and found his...
http://www.ecompressedair.com/accessories/valves/ca48-load-genie.aspx

 

[Redlunn]

What brand micro PLC/software did you use?

The PLC is an Allen Bradley Micro810. I got a few of them as freebies from our Allen Bradley rep. I think they cost around $100 with the LCD display and the software (Connected Components Workbench) is free. The PLC and software are not up to full industrial use but it's actually pretty powerful for how cheap it is. The model I used has only 8 digital inputs and 4 digital outputs so it's not appropriate for full garage automation but it seems like a good fit for compressor control.

 

[Tractor Camp]

Keep it simple - get yourself a mechanical water heater timer and mount to your starter. The clock motor of the timer is 220v so it is easy to grab power. Use the switch in the timer to interrupt the contactor coil. Put only the off trip in the timer, set for your usual end of the day. When your in the shop and want air, push the button on the timer and forget it. It will shut off at the end of the day.

As for the unloading issue, if you are turning off for the overnight and restarting the next day (and your tank check is in good shape) there should be enough leakage in the compressor that the morning start won't be an issue - never has been on any of my units.

 

[TheEquineFencer]

Keep it simple - get yourself a mechanical water heater timer and mount to your starter. The clock motor of the timer is 220v so it is easy to grab power. Use the switch in the timer to interrupt the contactor coil. Put only the off trip in the timer, set for your usual end of the day. When your in the shop and want air, push the button on the timer and forget it. It will shut off at the end of the day.

As for the unloading issue, if you are turning off for the overnight and restarting the next day (and your tank check is in good shape) there should be enough leakage in the compressor that the morning start won't be an issue - never has been on any of my units.

The idea of the timer is good if I kept "normal" hours. I was uo here working when I woke up at 2 am until about 5am when I took a nap and started back at 7 am, I'm still here now wiring and running conduit for the two new VFDs. Thanks for the ideas, I'll keep that type timer in mind as I'd never really thought of using one like that.