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DO-160-Section-18-Audio-Frequency-Conducted-Suscpetibility

RTCA DO-160 Section 18.0 Audio Frequency Conducted Susceptibility – Power Inputs

The RTCA DO-160 conducted susceptibility test standard provides test levels to test equipment for audio frequency conducted susceptibility of power lines. It is important for the equipment installer to ensure the test results satisfy the certification requirements of the installation.

The RTCA-DO-160 testing standard for conducted susceptibility assigns equipment to categories. Equipment that is ac powered can be included in categories R(CF), R(NF) or R(WF). DC equipment is either in category R, B, or Z. Included below is a breakdown of each category.

Equipment that falls under categories R(CF), R(NF), R(WF) and R must meet a number of different criteria. First the equipment is aircraft equipment for use on aircraft electrical systems. For ac equipment, the primary power is from a constant or variable frequency ac system. For dc equipment, the dc system is supplied from transformer rectifier units. Category R is assigned to dc systems. The other three categories, R(CF), F(NF) and R(WF) are all associated with ac systems.

Category B equipment is dc powered. This equipment used on aircraft electrical systems. These systems must be supplied by engine-driven alternator/rectifiers, or dc generators. The one clarification per DO-160G test standard is that category B equipment must have a battery of significant capacity is floating on the dc bus at all times. It is important to note that conducted susceptibility test levels for 14 Vdc equipment are exactly half of those required for 28 Vdc equipment.

The DO-160G EMC test standard specifies Category K equipment as having a voltage distortion level higher than the one for the ac supplies applied on category R equipment. As with other equipment in Section 18 conducted susceptibility testing, this equipment is intended for use on aircraft electrical systems. The equipment’s primary power is from a constant or variable frequency ac system.

The RTCA DO-160G EMC testing standard defines Category Z as dc equipment with certain criteria. Essentially, if the equipment is used on an aircraft electrical system not specified, then it is Category Z. RTCA specifies some examples of Category Z equipment. They include are dc systems supplied from variable-speed generators with specific characteristics. For instance, the dc power supply does not have a battery floating on the dc bus. Another characteristic is where control or protective equipment may disconnect the battery from the dc bus. The third characteristic is when the battery capacity is small compared with the capacity of the dc generators.

Keystone Compliance is one of the leading EMC test labs in the country. With seven EMC test chambers a substantial amount of test equipment, we are able to offer shot lead times on scheduling. Our engineers provide communication throughout the entire test program. If challenges arise during the testing, our engineers will provide engineering guidance and problem resolution. Our lab is 17025 accredited to RTCADO-160 testing. In addition to providing RTCA-DO-160G testing, Keystone is accredited to all previous versions of this military test standard as well.

Our EMC-EMI test lab can accommodate small and large items. Please contact us to see firsthand why so many manufacturers rely on Keystone Compliance to be their RTCA DO-160 test lab.

Looking for other testing to other sections of RTCA DO-160 testing? Click on the links below:

Modifications from one Version of RTCA DO-160 to the Next:

Changes from DO-160C Conducted Susceptibility Testing to DO-160D Conducted Susceptibility Testing

DO-160C referenced Figures 16-4 and 16-5 for DC ripple test requirements; these figures were moved to Section 18 as Figures 18-2 and 18-3.

Changes from DO-160D Conducted Susceptibility Testing to DO-160E Conducted Susceptibility Testing

The equipment category designators A and J were eliminated, and categories R and K were added.

Changes from DO-160E Conducted Susceptibility Testing to DO-160F Conducted Susceptibility Testing

New test for 270V dc input differential ripple to follow same curve as 28V Category Z, but at 4 times the amplitude was added. A common mode noise test has been added for 270V Category Z equipment. For test equipment that generate a continuous linear frequency sweep, the minimum (i.e., fastest) sweep rate has been slowed to make swept testing equivalent to stepped testing, especially at resonances.  An optional DC blocking network is added to the test setup figures to prevent damage to the signal source.

Changes from DO-160F Conducted Susceptibility Testing to DO-160G Conducted Susceptibility Testing

Changed secondary limit from a 1000W power limit to a 36A (pk-pk) current limit.  Added user’s guide and moved appropriate material to the guide. Corrected minor issues in existing figures.