Three basic types of air compressors exist: the centrifugal, reciprocating and rotary vane compressors. Centrifugal compressors are widely used in large machines and equipment, while the rotary vane and reciprocating compressors use helical screws and pistons respectively in order to decrease the pressure of the air. The compressor pumps meanwhile also have two variations, the oil lubed and oil-less. The oil-less pump are more expensive due to their more efficient use and function, while the lubed pumps work more silently and extensively in terms of removing air pressure.
The basic parts of an air compressor include the electric motor, receiver and pump. The receivers are either vertical or horizontal, depending on their size and capacity to hold and receive air. The electric motor meanwhile gives power for the compressor to work and reduce the pressure of the collected air. It runs a pulley wit two belts, which work by delivering power from the motor device to the pump pistons. Other accessories important in an air compressor include the flywheel fan and the crankshaft, in which the air is cooled after its pressure is reduced.
Air compressors are sometimes built with two-stage compartments or cylinders. In this case, these compressors are able to reduce air pressure twice, the first stage through a low-pressure cylinder, followed by a high-pressure cylinder. Most reciprocating compressors are built in two cylinders, while larger compressors such as the centrifugal types are built in single stage cylinder structures.
Air compressors, regardless of type, are used in five different applications. They can fill gas cylinders with pressurized air, as well as provide clean air to submerged surface supplied individuals such as scuba divers. Air compressors are also used to fill tires with air. Additionally, air compressors can be used to produce high volumes of moderate-pressure gas for industrial purposes such as petroleum oxidation. Lastly, the machines are used to cement plant bag house purging.
It is recommended that air compressors be installed with a magnetic starter. The magnetic starter prevents motor damage by keeping the compressor's thermal capacity. A compressor with no magnetic starter may intermittently apply high temperatures during compressing operations, which may result to motor overwork and eventual breakdown. Most manufacturers provide magnetic starters on their compressors, and users are required to have them installed before using the compressor device. Failure to use the starter may void the owner of the compressor's warranties and may face high costs of repair.