As
flight systems evolve from traditional hydraulic, to electrically-controlled/hydraulically
powered, to electrically (or optically) controlled/electrically
powered, one of the key design requirements for new power generation
will be the ability to provide high-quality power at variable
frequencies. An
equally important requirement will be for electrical equipment
and systems to be able to utilize the wide variable frequency
(or “Wild” frequency) of 350 to 800 Hz that is output by the
variable frequency generators. In addition, ground support and
test equipment capable of producing and handling “Wild” frequencies
will be required.
Read the
article in January 2007 Avionics magazine titled:
Perspectives: "Wild" Frequency
must move toward wide acceptance
See the results
of the survey:
Electrical Power trends in the military
and civilian aircraft industry
Questions
from readers with answers from our wild frequency experts
What
exactly is wild frequency?
Mike
T. MT
Wild frequency
is the 350 to 800 Hz output from the variable frequency generator.
This is a direct result of the aircraft engine speed. The variable
speed is result of the takeoff and landing and in Military aircraft
during combat maneuvers. Most of the time the engine produces
400 Hz.
I
thought 400 Hz was the AC standard on all aircraft?
Jim
W. OH
400
Hz is the standard aircraft frequency in use today. To have
a constant 400 Hz requires equipment that converts the varying
engine speed to a constant 400 Hz. This adds weight, cost and
maintenance. Using equipment that operates over the wild frequency
will eliminate this extra equipment.
What
will happen to all the existing avionics that are powered from
115VAC, 400Hz?
Peter
R. NY
Since
400 Hz is still the standard most equipment will not have to
operate from wild frequency. For aircraft that require wild
frequency operation there are companies like Behlman that make
frequency converters that can take the 350 to 800 Hz wild frequency
and produce a fixed 400 Hz frequency.
Is
there any equipment presently being manufactured that works
at the wild frequency?
Gary
V. PA
There
is a number of product designed to operate from wild frequency.
We have added a sampling of some of those product; flap actuator,
data recorder, anti-collision light system, AC/DC module, control
box, ice protection equipment. See items listed below.
Are
there any MIL Specs for wild frequency requirements?
George
B. CA
MIL-STD-704F
references wild frequency under Table II. AC normal operation
characteristics-variable frequency. There is also a commercial
aerospace test specification for Radio Technical Commission
For Aeronautics (RTCA/DO160) Section 16 which addresses the
new variable frequency range of 360-800 Hz.
How
could I verify if my equipment operates over the wild frequency?
Jack
F. CA
Companies
like Behlman manufacture frequency converters that can produce
the 350 to 800 Hz variable frequency. This variable frequency
can be used to power the UUT (unit under test) either manually
by varying a potentiometer or encoders or via a remote control
interface.
Information
and products regarding wild frequency
High-Performance
Front-End Converter for Avionics Application
This
paper presents analysis, modeling, and design of a low-harmonic,
isolated, active-clamped SEPIC rectifier for future avionics
applications. Simpler converter dynamics, high switching frequency,
zero-voltage-switching, and a single-layer transformer construction
result in an efficiency of 90% and a very low harmonic distortion
over 400-800 Hz line frequency variation.
Questions
and answers on "Origin of 400 Hz in aircraft"?
Demonstration
of Very High Power Airborne AC to DC Converter
This
paper describes the challenges inherent in developing high power
(>100kW) AC-DC converters for aerospace applications. Various
technologies and topologies were considered, analyzed and rated,
with an optimum design being chosen. Details regarding power
quality, magnetics design, and thermal management are discussed.
Performance results from demonstration hardware are provided,
including power quality, regulation, efficiency (98%) and temperature
results.
End
of the circuit breaker: smart power makes its mark
Computer
control of power distribution on aircraft and other integrated
platforms is helping systems integrators improve reliability,
safeguard sophisticated electronics from power spikes, and protect
not only aircraft and other expensive military and aerospace
systems, but also the men and women who operate them. An AIRINC
429 Tutorial
SAE
AE-7 Committee Minutes 29 April-1 May 2003
SAE
AE-7 5 year document review list. A 5-year review of AS 8023
is required. The committee needs to get a handle on which SAE
documents are in active use. Only keep 5-year review for active
document. Discussion on AS 1212 Electric Power Systems, Characteristics
vs. MIL STD 704: 704 is accepted as is DO-160. Has AS 1212 lost
its importance?...
Some
questions about " MAGNESIUM OVERCAST- The story of the
Convair B-36" by Dennis R. Jenkins
For
members of IEEE
High-power
variable frequency generator for large civil aircraft
Fault
tolerant, variable, unity power factor converters for aircraft
power systems
Converter
enhanced variable frequency power bus architecture
Unity
power factor power supply for use with variable frequency power
Aircraft
power supply 400 Hz and beyond
The
role of avionics in the all electric airplane
Available
for purchase from the Electronic Library of AIAA
Personnel
Licensing Advisory Circular
Aircraft
Maintenance Technician Licenses Type Ratings
Goodrich
On Board A400M
Airbus
has selected Goodrich Corporation to supply the flap actuation
package for its military transport aircraft,....
Data
Recording Products
A wide
range of data recording products with power test capability
to 800 Hz
Anti-Collision
Light System
Anti-collision
light system based on LED technology that operates on 115 VAC
form 360-800 Hz
Hi-Rel
AC/DC Module
Active
Power Factor Corrected over variable frequency 360-800 Hz
Airline
Control Boxes
Can
drive up to 10 standard actuators, up to 16 BUS actuators...power
supply frequency 360-800 Hz
Ice
Protection Systems
Products
ranging from ice protection systems, both anti-icing and de-icing,
to avionic systems and system monitoring equipment. Technologies
include wild frequency.
