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Powering a HUGE air compressor

SolarShedTed

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I'm building out a 20 foot shipping container to act as a large sandblasting cabinet. I'd like to power a huge 3 phase 240v 29a 10hp air compressor with solar. What would be the bare necessities for such a solar draw?

Any knowledge shared would be appreciated.

Thank You
 

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How many hours of run time will the air compressor be used for? What state are you in? Run during the day or night?

Totally off grid power or grid tied?
 
PF at 73% says you will need 30% additional apparent power from the inverter.
I assume the nameplate is the start surge maximum close to 30kW. Running should be less. I think I would want to plug it in and measure the actual start and run power draw. That is a monster.
 
I'm building out a 20 foot shipping container to act as a large sandblasting cabinet. I'd like to power a huge 3 phase 240v 29a 10hp air compressor with solar. What would be the bare necessities for such a solar draw?

Any knowledge shared would be appreciated.

Thank You

$10,000
 
208Y, 37A
That's 4440W (or VA) for each of three 120V phases.
I don't spot LRA locked rotor amps. Assume 5x nameplate, 185A

Running it is easy, with enough battery and/or PV.
3x Sunny Island 6048US and 3x Sunny Boy 7.7

The problem is starting. Rated surge power of Sunny Island is 11 kW for 3 seconds. Peak current is 180A for 60 ms, enough time to trip a breaker but probably not to start a motor.


A VFD that ramps the motor up to speed would help. Probably ramp fairly quick before pressure builds in the line.
I have had an issue with Sunny Boy giving a fault when trying to wake up while VFD is running. I think it is OK if VFD is off at the moment Sunny Boy wakes up from night or reconnects after generator/grid issues. DC coupling PV is another option, although I really like AC coupling.


Which equipment do you recommend? I just suggested about $16k to $20k (msrp) of inverters, although bargains can be had. We haven't even gotten into batteries and PV panels.

Silly thing is, VFD is an inverter that can run it just fine, and for cheap. If only we had a good MPPT SCC to take in PV and put out 350V or so.
 

Powering a HUGE air compressor​

FYI 10hp (35cfm) is puny for sandblasting. You'll spend most of your time waiting for the pressure to build.

Using a diesel screw compressor won't use any electricity and blasting will take 10 minutes instead of an hour. Buy one used, use it for five years then sell it for what you paid...... If your still alive.
 
Last edited:
208Y, 37A
That's 4440W (or VA) for each of three 120V phases.
I don't spot LRA locked rotor amps. Assume 5x nameplate, 185A

Running it is easy, with enough battery and/or PV.
3x Sunny Island 6048US and 3x Sunny Boy 7.7

The problem is starting. Rated surge power of Sunny Island is 11 kW for 3 seconds. Peak current is 180A for 60 ms, enough time to trip a breaker but probably not to start a motor.


A VFD that ramps the motor up to speed would help. Probably ramp fairly quick before pressure builds in the line.
I have had an issue with Sunny Boy giving a fault when trying to wake up while VFD is running. I think it is OK if VFD is off at the moment Sunny Boy wakes up from night or reconnects after generator/grid issues. DC coupling PV is another option, although I really like AC coupling.



Which equipment do you recommend? I just suggested about $16k to $20k (msrp) of inverters, although bargains can be had. We haven't even gotten into batteries and PV panels.

Silly thing is, VFD is an inverter that can run it just fine, and for cheap. If only we had a good MPPT SCC to take in PV and put out 350V or so.
Why not just use a Sunny Tripower CORE1 33-US ?
That will do 33Kw nominal. If he needs more he could get a CORE1 50US and that would do 50KW.
 
TriPower appears to be the 3-phase equivalent to Sunny Boy, and more watts.
Still need a grid-forming inverter. Three Sunny Islands would do it, but possibly not the starting surge.
There are 3-phase European models, not UL listed and require a 400V battery.


Depending on what percentage compressor is running vs. off, and total Wh/day needed, maybe 5kW to 15kW of PV is sufficient. Maybe more.

What would be nice is a big air tank and PV direct to VFD (no battery), vary speed of compressor for MPPT operation. To DIY and be economical, I would try to find a VFD that could handle highest Voc, and make a servo/PID control that varies VFD frequency.
 
The sunny islands are mostly needed to get the grid going. The start up load would be shared between them and the Core1.
 
The sunny islands are mostly needed to get the grid going. The start up load would be shared between them and the Core1.

AC coupled PV inverters contribute nothing to startup surge, but they can provide 100% of operating current with enough PV & sun.
It takes a few seconds for Sunny Island to swing frequency down and enable Sunny Boy or Core 1. Sunny Island has to provide the surge from batteries for a couple hundred milliseconds.
 
Convert it to a gas engine or diesel engine from electric motor and save few thousand dollars then mount the compressor outside the shipping container. Some things aren't worth trying to run on solar, i.e. welding machines, air compressors, plasma cutters etc... Sell the electric motor to recoup your losses.
 
PV powering an air compressor could save on fuel costs and be a great convenience, if total consumption is large. Problem is how much needed at once. If 10kW to 15kW of PV provides what's needed for daily use, could be great. That's a big motor, so smaller motor and different pully size could scale it to different output.

For occasional use, burning fuel as suggested is easiest and cheapest.
 
I don't see any mention of the other loads that will be required. Fans, filters, lighting, etc. This sounds like an exercise in futility. I may have missed it, but is the intent to use the shipping container as the storage for the blasting media, or is the whole operation going to be contained inside the container? I was assuming the latter. In that case, I'd be concerned about toxic paint and coatings too.

I've had some experience with having containers modified to have cyclone separators and such mounted on the roof, with flanges welded to the roof so hoppers and cyclones can be removed (if needed) for transport. The noise factor is tremendous, and we preferred (when possible) to put that stuff outside.

Shipping containers are very interesting to work with, and I've done a fair amount of it. But often what happens is someone has a preconceived idea that they are easy and cheap to adapt, and that often proves to be false. If I was bent on using one to do large scale sandblasting, I'd be thinking diesel generator on the roof, or end. Dust collection up top or on back side. And probably a 40' unit. Or if solar HAD to be used, maybe a lean to roof off the container for a BIG array. And do some google searches for how to baffle noise from things that create a lot of it. A good place to start is how they quiet compressors in oil fields.
 
I'm curious to see how this turns out. My first thought is "How much real estate do you have to mount the panels?" We have 6kW mounted on our roof. That's 24 panels. 12kW would be 48 panels. 15 kW would be 60 panels. The problem is that they rarely put out the full power! If you wanted to run "off grid" you would probably need 30% over. With batteries to act as a buffer, you would need a monster bank to handle the amperage needed. The idea of a diesel compressor would be a better way to go.
 
Hey everybody!!! He decided to return after nothing for 6 weeks!!!

Join us here:

 
Hey everybody!!! He decided to return after nothing for 6 weeks!!!

Join us here:

WTF is your problem? I had much more important business to attend to than replying to the thread I had started. Life occasionally takes turns. Covid fell upon me and my family. Sorry I didn't respond to your advice. But shaming someone because you felt ignored? Come on! Grow up.
 
How many hours of run time will the air compressor be used for? What state are you in? Run during the day or night?

Totally off grid power or grid tied?
I was hoping to run it totally off grid. I would expect to run it for 2 hours at a time (2 on 1 off) during daylight hours. But after reviewing the comments here I think the best course of action is to change out my compressor for a much more efficient one and go from there.
 
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