Why we use 400Hz Power Supply in Aircraft?


We use 400Hz power supply in aircraft for lighter, more efficient electrical systems, enabling smaller transformers and lighter cables.

Why we use 400Hz Power Supply in Aircraft?
Why we use 400Hz Power Supply in Aircraft?


400Hz power supply is utilized in aircraft due to several factors:

  1. Weight reduction: Higher frequency allows for smaller transformers and lighter cables, crucial for aircraft weight management.
  2. Efficiency: Electrical components like motors and transformers are more efficient at higher frequencies.
  3. Size reduction: Components can be smaller without sacrificing performance, vital in the limited space of aircraft.
  4. Compatibility: Many aircraft systems, including avionics and instruments, are designed to operate optimally with 400Hz power.
  5. Historical reasons: Early aircraft designs adopted 400Hz due to the availability of military surplus equipment.
  6. In-flight power quality: 400Hz minimizes electromagnetic interference, ensuring stable operation of sensitive avionic systems.
  7. Global standardization: The aerospace industry has standardized on 400Hz power, simplifying maintenance and compatibility across different aircraft models.
  8. Ground power compatibility: Most airports provide 400Hz ground power, facilitating aircraft servicing and maintenance.
  9. Heat dissipation: Higher frequency reduces heat generation in electrical components, enhancing reliability.
  10. Safety: 400Hz power reduces the risk of electrical shock and improves overall safety for passengers and crew.


Q: Why do aircraft use 400Hz power?

A: 400Hz power enables lighter and more efficient electrical systems.

Q: What are the advantages of 400Hz power in aircraft?

A: Size reduction, weight reduction, improved efficiency, and compatibility with aircraft systems.

Q: How does 400Hz power benefit aircraft performance?

A: It reduces weight, enhances efficiency, and ensures reliable operation of onboard systems.

Q: Is 400Hz power standard across all aircraft?

A: Yes, most modern aircraft utilize 400Hz power due to its advantages.

Q: Are there any disadvantages to using 400Hz power in aircraft?

A: Higher frequency may require more sophisticated equipment, but benefits outweigh drawbacks.

Q: Can ground power at airports supply 400Hz?

A: Yes, most airports provide 400Hz ground power for aircraft servicing.

Q: Does 400Hz power affect passenger experience?

A: No, passengers won’t notice any difference, but it enhances safety and reliability.

Q: How does 400Hz power impact maintenance costs?

A: It can reduce maintenance costs due to smaller, lighter components and standardized systems.

Q: Are there alternatives to 400Hz power for aircraft?

A: While alternatives exist, 400Hz remains the standard due to its proven advantages.

Q: Is 400Hz power used only in commercial aircraft?

A: No, it’s also common in military and private aircraft due to its benefits.