Why 400hz is used for aircraft systems

Aerospace manufacturing companies can achieve a lower weight by using Hz power. With Hz, airplanes require fewer generators or alternators to produce a sufficient amount of power. This reduces their total weight, thereby making it easier for airplanes to take off. If airplanes used a lower power frequency, they would require more generators or alternators, thus increasing their total weight. Another reason why Hz power has become so common is because it allows for the standardization of electrical devices and components.

Rather, some devices and components would be restricted to certain airplanes. Using Hz power ensures creates a standard for electrical devices and components. Since most airplanes use Hz power, their devices and components can be easily replaced. Airplanes use Hz power because it reduces their total weight while also providing standardization of their electrical devices and components. When researching some of the different types of washers used in the aerospace industry, you may We use cookies to improve your experience.

By your continued use of this site you accept such use. For more information, please see our privacy policy. Centralised power systems while cheaper to construct, do have several disadvantages. These include the balancing of the system, maintaining adequate voltage drops amongst others. Where fixed ground power is not available, mobile power units can be deployed. These are typically towed or mounted on vehicles and deliver power by utilising diesel generators. The amount of kVA required is dependant on the aircraft type and size.

During design processes, the amount of power required is calculated and suitable equipment installed. For point of use converters see blow , these are often standardised as 90 kVA units. For HZ systems, the impedance will be around eight times larger than normal mains systems and consequently voltage drop becomes a major issue.

In addition for normal four core cables, the distance between the centres of each phase is not equal [due to the neutral conductor taking up space in the image a3 is larger than a1 or a2 ]. This creates an imbalance and consequently the inductance of each phase varies.

This variation of inductance between phases, while not that important at mains frequency, become more pronounced at Hz and can lead to imbalanced voltages. To reduce any imbalance in inductive reactance, often special symmetrical seven core cables are used - with interspersed phases wrapped evenly around a neutral conductor. Generators providing Hz power use less copper in their windings and smaller magnetic cores than those of 50 or 60 Hz - making them lighter.

Given the relative short transmission distances in aircraft, the negative aspects of larger voltage drops at Hz are not so serious. The reduction in weight of equipment more than compensates for this.

Maintaining V at the aircraft plug in connector can be difficult; this is especially so where each phase is unbalanced. Several methods exist for ensuring the correct voltage level at the aircraft. Two methods which yield reliable results for point of use converters are:.

Commercial mains power at most airports operates on either 50 or 60 Hz. Frequency converters are required to change this to the Hz required for aircraft operation. No break power transfer: most modern aircraft operate a no-break power transfer. This means that consumption is transferred from the air-crafts own power generation units to ground generated power without any interruption.

Synchronization and switching over of the power supplies is carried out by equipment on board the aircraft. Tip: aircraft synchronism equipment is not always the most accurate. Employing frequency converters which can detect aircraft synchronization problems and react accordingly is a good idea.

Two common methods employed at larger airports are bridge mounted cable reel devices or apron buried pit systems. Need an account? Click here to sign up.

Download Free DOC. Download Free PDF. Why we use Hz Power Supply in Aircraft? Areeb Ahmed. A short summary of this paper. Origin of Hz in Aircraft Is there any particular reason, why the standard aircraft power supply is Hz? As aircraft fly higher, faster and grow larger, the services that the power supply has to satisfy also grow more complex. In civil aircraft this means more power to the galley units, environmental control and passenger entertainment systems, while increased power demands for actuators, lighting systems, avionics and heating.

The primary function of an aircraft electrical system is to generate, regulate and distribute electrical power throughout the aircraft. The aircraft electrical power system is used to operate a aircraft flight instruments, b passenger services. Essential power is that the aircraft needs to be able to continue safe operation.

Passenger services power is the power that is used for cabin lighting, operation of entertainment systems and preparation of food. Aircraft electrical components operate on many different voltages both AC and DC. AC power, normally at a phase voltage of V, is generated by an alternator, generally in a three- phase system and at a frequency of Hz. However, higher frequencies are also more sensitive to voltage drop problems.

There are two types of drops: resistive and reactive. Resistive losses are a function of current flowing through a conductor with respect to the length and size of the conductor.