RTCA DO-160 – Section 18.0 – Audio Frequency Conducted Susceptibility – Power Inputs
This test determines whether the equipment will accept frequency components of a magnitude normally expected when the equipment is installed in the aircraft.
These frequency components are normally harmonically related to the power source fundamental frequency.
This section of DO-160 is intended to provide test procedures and test levels that can be used to test equipment for audio frequency conducted susceptibility of power input lines.
It is the responsibility of the installer to make sure the test results satisfy the certification requirements of the proposed installation.
Test designation for equipment consists of:
– For ac equipment: R(CF), R(NF) or R(WF)
– For dc equipment: R, B, or Z
Categories R(CF), R(NF), R(WF) and R
Equipment intended for use on aircraft electrical systems where the primary power is from a constant or variable frequency ac system and where the dc system is supplied from transformer rectifier units, is identified as:
for ac equipment: Category R(CF), R(NF) or R(WF),
for dc equipment: Category R.
Dc equipment intended for use on aircraft electrical systems supplied by engine-driven alternator/rectifiers, or dc generators where a battery of significant capacity is floating on the dc bus at all times, is identified as Category B. Unless otherwise specified, tests levels for 14 Vdc equipment are half those shown for 28 Vdc equipment.
Dc equipment that may be used on all other types of aircraft electrical systems applicable to these standards is identified as Category Z. Category Z shall be acceptable for use in place of Category R or B. Examples of this category are dc systems supplied from variable-speed generators where:
The dc power supply does not have a battery floating on the dc bus, or
Control or protective equipment may disconnect the battery from the dc bus, or.
The battery capacity is small compared with the capacity of the dc generators.
Equipment intended for use on aircraft electrical systems where the primary power is from a constant or variable frequency ac system and characterized by a voltage distortion level higher than the one for the ac supplies applied on category R equipment. Category K shall be acceptable for use in place of Category R.