The energy level of air or gas flowing through it is increased by the action of the rotor blades which exert a torque on the fluid which is supplied by an electric motor or a steam or a gas turbine.
The energy level of the fluid increases as it flows through the compressor due to the action of the rotor blades which exert a torque on the fluid. Compressors are typically driven by an electric motor or a steam or a gas turbine.