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# Thread: Air Compressor takes a nap

1. ## Air Compressor takes a nap

My air compressor as decided to lay down on the job and I have a small aluminum job coming up this weekend so I'll be needing the plasma. I've searched and read but I still can't find a answer. I'll be hooking up a cylinder of compressed air. Lws pointed me toward med air. Its cheap and readily available. My question is how long would I expect this cylinder to last? Its a 335 cubic ft. Is it feasible or do I need to go ahead and bite the bullet and repair the compressor? \$\$\$\$

2. Originally Posted by sledsports
My air compressor as decided to lay down on the job and I have a small aluminum job coming up this weekend so I'll be needing the plasma. I've searched and read but I still can't find a answer. I'll be hooking up a cylinder of compressed air. Lws pointed me toward med air. Its cheap and readily available. My question is how long would I expect this cylinder to last? Its a 335 cubic ft. Is it feasible or do I need to go ahead and bite the bullet and repair the compressor? \$\$\$\$
335 cf @ what PSI..??

your plasma consumes how many CFM @ 60?? PSI..?? (60 is a guess... give us your real number)

then we will have to find the calc to figure the conversion..

how much cutting do you need to do??

What is the matter with your compressor??

3. Originally Posted by H80N
335 cf @ what PSI..??

your plasma consumes how many CFM @ 60?? PSI..?? (60 is a guess... give us your real number)

then we will have to find the calc to figure the conversion..

how much cutting do you need to do??

What is the matter with your compressor??
Its a 3phase running off of a rotary phase converter or (add a phase) as some like to say. It burnt a leg up on my motor starter so a a new starter and some wiring, motor repairs and the compressor needs the head rebuilt with new unloaders (been putting that off for awhile). Fix it all at once is gonna be cash!

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too many variables are missing to think of something...

what makes you think your compressor will be \$\$\$ ?

the air cylinder is a what pressure ? 2200, 2500 if it's the case it should last about the same time an oxy bottle, what is your post flow time on your plasma, pressure required for your alu. thickness...ahhh so many questions.

a guy stuck in the fields would think of stealing air from a large truck tire...

darn...hn80 beat me to the finish line lol

5. OK, you guys got me. I have no idea what PSI is in a Med air cylinder because I've never messed with one. My plasma says 6.7scfm @ 90psig. I'm cutting some 6"x 5/8" flat stock. Be about 16 square cuts total. I know the compressor is gonna cost \$\$\$\$ cause its a Quincy.

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it may be cheaper to rent or buy a small compressor and work with it, slower but it 'll get the job done.

7. The compressor itself has had unloader problems for a while now. I got one unhooked. Its a 2 stage 340 on a 200 gallon tank. I had an electrical issue on the starts the other day and it burnt one of the legs up on the out starter. Cooked the terminal and burnt the wire off. Probably ruined the whole thing. It still pulls together but I'll bet the contacts on that leg is fried crispier than saterday morning bacon.

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your contactor and wire frying has probably been caused by that defective unloader valve, as it tried to start loaded. Some time also combined with a defective check-valve at the tank entrance ( also seen parts of the head valve plates stuck in check valve...) Don't tell us it has no fuses or breaker Ha!

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HN 80 if you get your hand on a formula to calculate cfm at different psi and psi at different cfm or whatever...I'm interested

10. Originally Posted by snowbird
your contactor and wire frying has probably been caused by that defective unloader valve, as it tried to start loaded. Some time also combined with a defective check-valve at the tank entrance ( also seen parts of the head valve plates stuck in check valve...) Don't tell us it has no fuses or breaker Ha!
Well you hit the nail on the head. Lol. Yes its breakered but its over killed like everything else I do.

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