subject: A Guide To Picking An Air Compressor [print this page] Folks frequently get confused concerning selecting the most appropriate air compressor to operate their equipment. Quite simply, there are several aspects you need to look at when choosing an air compressor for your garage or store.
Lets look at these elements:
1. Horse power rating
Many people are of the opinion that the higher the horse power, the more effective is the air compressor. However, all horse power ratings aren't equal and can even be misrepresented. For instance, when you visit a hardware store to get a 6 hp air compressor, you find one that is priced really cheap. So, why is 6 hp commercial model so expensive? Well, 6 hp is 6 hp, right? Not always, because when selecting an air compressor, you need to see the power that the air compressor draws. If if needs 15 amps from a 110 volts circuit, then you're actually getting around 2 hp. So, the 6 hp rating on the compressor is inflated.
In order to generate 6 horse power, you would require at least 24 amps from a 220 volts circuit. For that reason, if you're thinking about a 6 hp electric compressor, you should get a industrial compressor, instead of buying a cheaper unit from a hardware store.
2. How much PSI will you need?
For all newcomers, PSI means pounds per square inch and many of the compressors in the US are rated in this way. In the EU, they are measured in bar. When selecting an air compressor, you may want to settle for 90 PSI for correct operation. However, still you'd have to have a air compressor that has higher shut-off pressure. Air compressors in hardware stores are single-stage and have a shut off about 126-135 PSI. All light duty air compressors shut off at around 100 PSI and so are fine for light duty garage use. However, if you are planning to use power tools, then more is definitely better. Most of the industrial air compressors are two-stage, that is they build up the shut-off pressure in two separate stages. The first stage builds up at about 90 PSI and the second state builds it to 175 PSI.
3. CFM
CFM (Cubic Feet per Minute), is a measurement of volume, that is the amount of air which is being moved. Air tools need specific volume of air to run effectively. Although every manufacturer attempts to impress that his product gives higher CRM ratings at various pressures, your actual concern when choosing an air compressor should be on how much you'd get at 90 PSI as this is what many of the air tools require for effective operation.
4. Tank size
The tank size of air compressor is expressed in US gallons. Lots of people get confused about the best tank size when picking an air compressor. Firstly, you shouldn't mistake a large tank with more run time for your air tools. If tools are used intermittently, then a large tank is good. However, should you want to use your tools continuously, you would do better with a small tank and large enough motor and pump. This will ensure you wont run out of air.
You can now effectively select an air compressor equipped with this useful information. Finally, you have to decide on what you're likely to use your air compressor for and choose the right model.
