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What is the main reason for using 400 Hz instead of 60 Hz AC power supply in the aircraft?
Induction motors turn at a speed proportional to frequency, so a high frequency power supply allows more power to be obtained for the same motor volume and mass. Transformers and motors for 400 Hz are much smaller and lighter than at 50 or 60 Hz, which is an advantage in aircraft (and ships).
What does a frequency of 400 Hz mean?
400Hz is a type of frequency within Alternating Current (AC) electrical power, which has become the standard for weapon systems, aerospace, and aircraft industries across the world. It has become the standard of the aircraft and aerospace industry because of its lightweight, reliability, and high power capability.
Why was 400 Hz chosen for power supply?
The reason 400 Hz was chosen over the traditional 50/60 Hz is because of weight. A 400 Hz generator is much lighter, thus saving fuel, and the need to support a heavier unit making the airframe lighter.
Which is smaller 400 Hz or 800 Hz?
With a 400 Hz input, the ripple voltage is 800 Hz (hence smaller), having no impact on the power supply performance. For power supplies greater than 50 W, most AC-DC power supplies have active Power Factor Correction circuitry.
Why is the APU used at 400 Hz?
The APU is used primarily to start the aircraft engines, but is also used to run accessories on the plane while passengers are on board and for preflight checks by the crew when the aircraft has left the gate. The reason 400 Hz was chosen over the traditional 50/60 Hz is because of weight.
Why do we need a 400 Hz generator?
A 400 Hz generator is much lighter, thus saving fuel, and the need to support a heavier unit making the airframe lighter. MIL-STD-704F is the specification that covers Aircraft Electrical Power Characteristics for US military aircraft, and covers in detail all aspects of the requirements.