An air compressor is a pneumatic device that converts energy into potential energy stored in compressed air (i.e. compressed air). The compressor pushes more and more air into the storage tank, which increases the pressure. A compressor is a mechanical device that increases the pressure of gas by reducing its volume. Since the gases are compressible, the compressor also reduces the volume of gas. The main activity of the pump is to compress and transport fluids. The three most common air compressors are reciprocating, rotary and centrifugal air compressors.