Two air compressors

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mkingaz
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Two air compressors

Post by mkingaz »

So I'm fairly new to the CNC plasma table world but I have an issue and its only 1 220 plug in my garage. I need a bigger air compressor, currently running a 30 gal tank and I thinks it is a 3 hp but not big enough to cut any good size project. I'm thinking I need a min of 11CFM at 90psi. The question I have is could I run two 120 volt 30 gal air compressors (I could put on different breakers) join the air lines together and make this work and possible be cheaper than a new full size air compressor? I was already shopping for a new larger one but still have electric issues in a home I will only be in for another 7-9 months.

Thanks,
robertspark
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Re: Two air compressors

Post by robertspark »

I run two when needed for sand blasting

I have 2x3hp ones
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djreiswig
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Re: Two air compressors

Post by djreiswig »

If you set the pressure switches differently, you could do a lead/lag setup. Make the second one turn on at a slightly lower pressure and it will come on when the first one can't keep up.
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ctgolfer1
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Re: Two air compressors

Post by ctgolfer1 »

Considering your electric issues and the fact that you will be around for just a few months, storing more air may be a better option. You can find old, used 500 gallon propane tanks cheap sometimes from a propane dealer that rents out tanks or you could build a tank. Until you get 220 out to the shop it would be hard to find a compressor that runs on 110 and has enough cfm to keep up.
Another option would be to take an old compressor and rig it up with a gas engine to get you by for now, just add that air to your electric tank.
One other option would be to get a tank of nitrogen from a welding shop, they rent the tanks for about $100 a year and refill our tanks for $18.00. Tee it into your airline with a regulator set at 70 or 80 lbs and it would only feed in nitrogen when your compressor is coming up short. Nitrogen is really nice to cut with especially on stainless.
Good luck man.
mkingaz
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Re: Two air compressors

Post by mkingaz »

thanks for the input people. I know I really want and will get a larger air compressor once the house is done, just trying to figure out how to get by in the mean time without constantly stopping my cut's and waiting for the air to catch up.

Thanks again,
robertspark
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Re: Two air compressors

Post by robertspark »

mkingaz wrote: Thu Sep 19, 2019 6:41 pm So I'm fairly new to the CNC plasma table world but I have an issue and its only 1 220 plug in my garage. I need a bigger air compressor, currently running a 30 gal tank and I thinks it is a 3 hp but not big enough to cut any good size project. I'm thinking I need a min of 11CFM at 90psi. The question I have is could I run two 120 volt 30 gal air compressors (I could put on different breakers) join the air lines together and make this work and possible be cheaper than a new full size air compressor? I was already shopping for a new larger one but still have electric issues in a home I will only be in for another 7-9 months.

Thanks,
what is the amperage rating of your 220v output?

I am probably not best to advise as I am in the UK and all outlets are 230v (we don't have 110.... unless it's a shaver socket in the bathroom)

from what little I know about the us, you have 2 hot wires at 110v which provide you with 220 as they are in phase.... 110v to neutral or ground.... do each of the 110 hot wires have a fuse or breaker or is there one two pole breaker for the 220v

if so / either way, what is its rating?

although it doesn't help you out.... I have 2 compressors 3hp which each draw 2200Watts at 230v each (~10A each), I also have a powermax45 which requires about 30A.... total load is about 50A plus lighting the breaker in my garage is about 40A.... so with a running current of over 40A it's a bit close.... however in practice it's never tripped but that is because fuses and breakers have a trip curve so that they can withstand X amount of current for so long before they trip....


example a 40a type C breaker will only trip if it's subjected to 40A for about 2000 seconds continuously (about 1/2 an hour)..... I don't know how the fuses or breakers are rated in the us... but they all should offer some parity

Image


my point being, I think you need to provide a bit more information on your breakers and fuses protecting the two 110v hot wires, such as their ratings and maybe if they have any numbers or letters on them (yes the UK will be a little different as we have different standards and regulations but that is what Google is for)

the normal legal stance is to obviously get a qualified electrician to do your alterations as you generally can't see electricity and it can bite and or occasionally kill depending on circumstance, conditions and disposition
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