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How to choose the right air compressor:

First, you need to know the size of air compressor you need. The following tips should be noticed.
1. Get to know the air requirement of your tool.
As we all know, some tools consume more air comparing to others, for example, the pneumatic nail-guns, staplers that consume less air, on the contrary, the air grinders and sprayers need much air. So we need to know the air requirements or cubic feet per minute of the tools, whatever you are using or planning to use them. Generally, you can find a usage rating for CFM consumption at a recommended PSI on the tools or within the enclosed owner‘s manual provided by the tool manufacturer.
a. One tool at a time. If you are alone to use the compressor, you have to know the required largest CFM of the tool you may use, and then choose the right size accordingly.
b. More than one tools at a time. You need to add up all the CFM of all the tools you may use at the same time, and then determine the size of compressors you need accordingly.
c. If your compressor performs well below or above 100PSI, you should to know that the PSI and CFM is contradictory to each other, which means you drop in PSI usage, you get a slightly higher CFM, and vice versa.

2. Refer to the delivered or free CFM rating instead of the displaced CFM rating.
Actually, the displaced CFM and delivered or free CFM are different. The displaced CFM is the perfect standard rating for compressors that can not exist 100% in real world. This CFM comes out by a compressor working in a prefect environment at a total efficiency. As a result, you should decide the right size compressor by referring to the delivered CFM.

3. Choose the right compressors
The correct size number should be your decided CFM and add 20% more. Then what you have to do is pick out the compressors with the matched delivered CFM.

Second, you have to understand what the horsepower rating is.
As a matter of fact, horsepower is not the only component in the processes of producing air by air compressors, and the compressor pump has worked together with horsepower to produce the needed air. You have to remember that bigger the horsepower does not necessarily mean more air produce. But horsepower works together with a quality pump that can produce adequate CFM you need.

However, you should be aware of the differences between the horsepower from manufacturers and the real horsepower of the compressor you would like to buy. Most of the time, the horsepower provided by manufacturers are not the real horsepower of a compressor. It is the peek horsepower, which is the horsepower when the machine is getting start. Generally, the start-up horsepower is 1.5 to 3 times stronger than the normal running horsepower. So it is the real horsepower instead of the peek horsepower that we should care about.

Third, provide the right voltage to run the compressor.
The voltage is optional to different sorts of compressors. For most of the time, the electric compressors can run properly with a standard 110-volt circuit. However, the electric wheelbarrow compressors is flexible to run with the power varied from 110-volt to 220-volt, which is depending on available power supply for the job. On the other hand, if no other optional gas-powered compressors are available and more air is required, usually the 220-volt motor would be your only choice. Therefore, when you want to buy a stationary shop compressor, you have to know the power supply at your disposal (208v, 230v, or 460v), and the power-phase (single-phase or three-phase).

Sometimes, the power supply failed or is far away, but we do not recommend using a generator to power your compressor for substitute. As generators may damage the compressors if sudden fluctuation in power occur, and it is considered improper usage of compressor and will void any warranty on it. However, we do recommend using a gas-powered compressor when power supply is unavailable, and applied the suggested length and gauge of power cord involved in users manual. You better choose longer (and larger diameter) hose instead of a longer cord. It is commonly known that most electric tools have initial start-up surge which mean more powers are required to start-up than to run, and the disparity of start-up power and normal run power can be as large as 3 times. This also means the amp-draw is 3 times as much.

Forth, use the right mode to run compressor, Stop-start or constant-run.
Stop-start mode means that pressures switch control the pressure level of high and low in the tank by automatically turning on and off the compressor. When the pressure level is lower than designed PSI in the tank, it will auto-turn on. Conversely, it will auto-turn off when the pressure level higher than the designed PSI. This operation is suitable for smaller electric, direct-drive compressors and some smaller wheelbarrow electric compressors.

Constant-run mode means to run the pump continuously without stopping the motor. A pilot unloaded-valve is provided to level the designated pressure in the tank. The valve will open to atmosphere when the tank reaches the high-pressure setting so as to keep the compressor running. The valve will closed when the PSI is come to normal and then repeat the work of direct air back into the tank. This mode is more often applied in such tools that heavy and constant flow of air without interruption is required, for instance, a grinder, or sander, or a sprayer.

Generally, constant-run mode is usually used for a compressor that stops and starts more than 20 times per hour so as to protect the compressor from excessive overheat. As we all know, the frequent stop and star of compressor within a short time will produce a huge amount of heat which is more than the motor stays running all the time. Therefore, we should choose the right mode of compressor depending on the actual situation.

Fifth, buy the most suitable compressor, oil-less or oil-lubricated.
Almost all the reciprocating compressors are provided with a series of pistons that will pump up and down inside their individual cylinder for the purpose of compressing the air to a higher pressure. The rub can create friction and heat. So measures have to be taken to prolong the life of the pump, such as lubricate with oil and have a Teflon-type lining in the cylinder.

Oil-less compressors are widely used for lighter use applications. They are able to run off-level without worry. But the advantages and disadvantages are half and half. They are of low-maintenance, but tend to wear much quicker due to more heat created, and the repair costs would be extensive.

Oil-lubricated compressors are capable of keeping the pump running cooler and lasting much longer if they are well maintained. It is of vital importance to make sure the compressor sits level so as to ensure that the lubricated oil is effective and reach all cylinders. If run off-level, it can do heavy damage to the cylinders over a short period of time. And it is considered improper usage and difficult to claim warranty.

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