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How to Select an Air Compressor


Quiz Questions

1.Compressed air, or pneumatic devices are therefore characterized by a high power-to-weight or power-to-volume ratio.
True
False
2.

Not as fast as electricity, nor as slow as hydraulics, compressed air finds a broad field of applications for which its response and speed make it ideally suited. Where there is an overlap, the choice often depends on cost and efficiency, and _________is likely to hold the advantage.

Air
Hydraulic
3.

Reciprocating single acting compressors are generally of one-stage or ______ design. Compressors can be of a lubricated, non-lubricated or oil-less design.

Two- stage
Three stage
Four stage
4.

In the single-stage compressor, air is drawn in from the atmosphere and compressed to final pressure in a single stroke. The single-stage reciprocating compressor is illustrated in Figure 1. Single-stage compressors are generally used for pressures of 70 psi (pounds per square inch) to 135 psi.

70 psi to 135 psi
300 psi to 1000 psi
1 psi to 35 psi
5.

In the two-stage compressor, air is drawn in from the atmosphere and compressed to an intermediate pressure in the _____ stage. Most of the heat of compression is removed as the compressed air then passes through the intercooler to the second stage, where it is compressed to final pressure.

First
Second
6.

Hospitals and laboratories usually purchase lubricated design

True
False
7.

Controls are not required for all compressors in order to regulate their operation in accordance with compressed air demand. Different controls should be chosen for different types of compressor applications and requirements.

True
False
8.

Most compressors are driven with electric motors, internal combustion engines, or engine power takeoffs. Three types of drives are commonly used with these power sources.

True
False
9.

V-Belt Drives are most commonly used with electric motors and internal combustion engines. V-Belt drives provide great flexibility in matching compressor load to power source load and speed ____________. Belts must be properly shielded for safety.

At minimum cost
At maximum cost
10.

All compressor motors should be equipped with overload protection to prevent motor damage. Some motors are furnished with built-in thermal overload protection. Larger motors should be used in conjunction with starters, which include thermal overload units. Such units ensure against motor damage due to low voltage or undue load imposed on the motor.

True
False
11.

The optimum compressor installation for a shop is:

Start with a small unit Then, as expansion takes place, instead of replacing the single unit with a larger capacity single unit, another unit of the same size is installed and so on, as the expansions grow.
Start with a small compressor in the shop, when expansion take place, replace the small one with a big central compressor and have piping to all the different stations in the shop.