roninjiro Posted November 17, 2006 Share Posted November 17, 2006 i just bought a two stage 120 gal. air compressor. problem is it as a 1/2 hp motor on it, too small but works anyway. i guess all i have to do is upgrade the motor, what do you guys think? and lets not forget i bought this setup for only $50, and it works flawlessly<-------- i dont care who ya are, you cant beat that deal!!! Quote Link to comment Share on other sites More sharing options...
Cruez Posted November 18, 2006 Share Posted November 18, 2006 Nice... the compressor itself is usually the expensive piece... grab a good motor at Grainger or something and go with it.. I wish I ran across a deal like this.. Quote Link to comment Share on other sites More sharing options...
240zV8 Posted November 18, 2006 Share Posted November 18, 2006 a good 5hp motor should be about $100-$150 new. You could probably find a used one for cheap. I just wanna know who would put a 1/2 hp on a 120 gal..lol...must take forever to fill. I have a 26 gal but i'm looking into adding a extra tank to it to make it about 80 gal (just gotta find the right deal on a old tank someone has sitting around). Great deal, just make sure ur pump is also made to handle more hp if you get a bigger motor. Quote Link to comment Share on other sites More sharing options...
roninjiro Posted November 18, 2006 Author Share Posted November 18, 2006 i was searching around for this compressor on the web and found out this is originally supposed to have a 5hp motor on it and run about 15csfm at 175psi. Quote Link to comment Share on other sites More sharing options...
240zV8 Posted November 18, 2006 Share Posted November 18, 2006 i was searching around for this compressor on the web and found out this is originally supposed to have a 5hp motor on it and run about 15csfm at 175psi. yea, even my 26 gal has a 5 hp (2 real hp). So you'll be real happy if you get a 5 hp motor on that tank. Make sure you get a dual cylinder pump for that size tank to. Quote Link to comment Share on other sites More sharing options...
roninjiro Posted November 18, 2006 Author Share Posted November 18, 2006 i has the dual cylinder pump already, i guess i should look forward to the 5hp motor then. cool beans Quote Link to comment Share on other sites More sharing options...
Tony D Posted November 29, 2006 Share Posted November 29, 2006 The horsepower of the motor will be determined by the compressor capacity. If you look closely at compressors (doesn't matter which manufacturer) you will see the stuff in the 3 to 10 HP range is very similar. In one manufacturer's cars, you can see they use the SAME compressor for 3,5, and 7 HP units. The ONLY thing that changes on the machine is the pulley size on the driver motor, and the HP rating of the motor. in other words, the speed up the pumps for capacity increase. Chances are good if you can do an amp check or check out particulars on the compressor you have, that you will be able to put a 7HP motor, as well as a 7HP motor pulley on it, and get that amount of capacity out of the compressor you have. Truthfully, a 15scfm compressor should only require about 3HP at 125psi, so the increase to 175 is accomplished through turning the compressor slower, and running one motor size higher (5hp). On your setup you should easily be able to run a 7.5HP motor with the 5hp pulley and NEVER enter the service factor of the motor (this will NOT be the case if you install the 5hp motor!). When you check the prices on a 5HP and a 7.5Hp motor, you will see the prices are almost identical. You will NOT pay any more for electricity as the compressor will only use what it needs amperage wise. What you will get is a return on investment in a cooler running electric motor, and after it runs for a while, if you determine you need more capacity, you can do an amp check on the motor while running at full 175psi (just before cut-out) and determine what kind of drive pulley size increase you can tolerate and still be within the capacity of the motor... Just make SURE the motor you buy is compatible with the VOLTAGE you have available at your house. In many places there is 208VAC, and not the standard 220/230/240VAC! This will BURN UP a motor very quickly. If you have low line voltage, you will benefit from the larger motor as it will be able to handle the additional amperage load without the killing heat the 5HP unit would produce. I do this all day long (Work as a Field Engineer for Ingersoll Rand), so if you have any questions, PM me. You can't go wrong with a 7.5 HP motor on that frame, it gives you many options down the road, for little cost if any right now. FYI, the current I-R model 2475N7.5 has a 7.5HP motor on it, and it's specifications are 24.3 CFM at 175psi, and 24.3 CFM at 90 psi The model below it 2475N5 has a 5HP motor on it, and it's specifications are 17.2 CFM at 175psi, and 16.8 CFM at 90 psi The model belo that is 2340L5 also has a 5hp motor on it, and it's specifications are 15.1 CFM at 175 psi, and 15.8 CFM at 90 psi Those are the "upmarket V-Configuration" compressors, The models with two cylinders inline like the SS5L5 only have a 135psi capacity, so that should give you an example of what yours should be capable of with various motors and pulley sizes to drive the compressor at various speeds. Always check running amps to know if you are overloading your circuit or motor. Good Luck! Quote Link to comment Share on other sites More sharing options...
roninjiro Posted December 1, 2006 Author Share Posted December 1, 2006 thanx alot, it makes alot more sense now due to your post. i will go ahead and do that then. thanx again tony Quote Link to comment Share on other sites More sharing options...
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