An auxiliary power unit (APU) refers to a self-contained device or system utilized in various industries to supply power independently from the primary power source. It is predominantly used in vehicles, aircraft, and other machinery that require secondary power or backup power during operation or when the primary power source is unavailable.
In the context of vehicles, an APU typically serves as an additional power provider to support various non-propulsion functions. It delivers electrical power for essential systems such as air conditioning, heating, lighting, and electric motors when the main engine is turned off or unable to sustain these operations. This auxiliary power unit ensures the continuous functionality of crucial components, enhancing comfort and safety for both passengers and crew members.
In aviation, an APU is an onboard system found in aircraft that offers a self-sustained source of energy to power multiple aircraft systems. This self-contained unit generates electrical power to maintain cabin pressurization, provide air conditioning, power cockpit instruments, and start the aircraft's main engines. Furthermore, APUs can also provide compressed air for engine starting, hydraulic power for utility functions, and emergency electrical power during critical situations.
Overall, an auxiliary power unit denotes a supplementary power source that plays a vital role in maintaining the normal operation of diverse machinery by delivering uninterrupted and independent power, thereby ensuring the efficiency, safety, and comfort of the equipment or vehicle.
