A pump is a device that moves fluids liquids or gases, or sometimes slurries, by mechanical action. Pumps can be classified by their method of displacement into positive displacement pumps, impulse pumps, velocity pumps, gravity pumps, steam pumps and vacuum and valveless pumps. There are three basic types of pumps positive displacement, centrifugal and axialflow pumps. In centrifugal pumps the direction of flow of the fluid changes by ninety degrees as it flows over an impeller, while in axial flow pumps the direction of flow is unchanged. When a casing contains only one revolving impeller, it is called a singlestage pump. When a casing contains two or more revolving impellers, it is called a double or multistage pump. Vacuum pumps are simply compressors that take in contained gas at a pressure lower than atmospheric pressure, compress it, and discharge the gas at atmospheric pressure creating a vacuum where the contained gas originated. In an electric motor, the moving part is the rotor, which turns the shaft to deliver the mechanical power. The rotor usually has conductors laid into it that carry currents, which interact with the magnetic field of the stator to generate the forces that turn the shaft. Alternatively, some rotors carry permanent magnets, and the stator holds the conductors. Specifications. Speed 5 GPM. Height 0.38 in.. Width 2.75 in.. Length 2.75 in.