I have a 60 Gallon Kobalt A/C. It's about 3 years old, hasn't been used much until recently. It runs all my tools fine, as well as my paint gun. When sandblasting though it runs constantly........but i still have enough pressure to blast with. Down the road I will probably put a bigger motor and 2 stage pump on it, but for now I was wondering if anyone has ever tried bumping up the drive ratio on there store bought compressors to turn the pump faster, nothing radical maybe from like 3:1 to 2.5:1? Worst comes to worse the pump or motor just wears out faster........
Sort of... I had a 4 hp Sears oilless POS that finally broke a rod and spit parts... That POS had the pump as part of the motor; direct drive. So, I went to HF and bought their large V twin pump and used an older 4 hp comp belt drive motor. I was working on this on a weekend so I had a limited amount of drive pulleys. I did the math and I think it figured to a 2.5 drive, but I had a 3. What happened was during constant use sandblasting in summer, it would eventually kick the thermo switch ...maybe in 3/4 hour. So I found a 2-3/4 and it cured it. I was suprised a 1/4" would make a drastic change. I run two comps when blasting. My twins never shut off, I just set up a fan on each on real hot days.
I haven't but I did have two visually nearly identical compressors here, sanborn units. Both had the same 2 stage pump and fly wheels. One unit was a 1700 rpm 220 and the other was a 3400 rpm 3 phase. The motor pulley was a bit smaller om the 3400 rpm vs the 1700 rpm motor. The 3 phase unit put out almost twice as much air, was almost twice as loud, and gets almost twice as hot. This is an industrial sanborn with the exact same pump as the commercial/heavy hobbyists unit.
I have regeared but usually to slow down the pump.I had 2 60 gallon tanks at work that were old dead compressors and I bought a nice 220 5 HP from hrainer and the large v style pump from harbor freight and ran it 15% slower to keep heat and noise down. It would run long but keep up with all shop requirements. And it was nice and quite. Will be building a similar unit for my house
I checked mine, the motor was actually just luke warm not hot during running so Im thinking I could push it a little harder......... and perhaps be able to let the pump catch a few minute break between cycles. It is 220V btw.
UPDATE: Well I did it....I installed a 5" pulley on the motor, original was 4". After doing some calculations thats an increase of 25% in Rpms on the Compressor. It actually smoothed the sound of the compressor out some and is noticeably faster at filling the tank. I used the same belt, redrilled holes on the mounting plate and went with a Chicago aluminum pulley to cut back on weight, it weighs about 1/3 less the original cast iron pulley so that should help cut back on motor lag. Anyways thought I'd post, I'll let yah know if/when she blows. Should get a good workout next weekend blasting and painting all day!
My 5 HP dual stage US compressor is at least 50 years old. I rebuilt it in the 70's, and along the way I ported the head, changed the drive pulley to 9" for a 1.89 :1 ratio. I have run it this way for over 30 years. It's a little loud but makes pretty good air up to 175#
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