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Authors Name, Affiliation, and E-mail:

Dr. Wolfgang Kürner, Airbus, wolfgang.kuerner@airbus.com

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Reason for Change:

Section 19 includes tests regarding a possible susceptibility
to magnetic fields coupled into equipment and magnetic and electric
fields coupled into wiring.

Possible interferences caused by low frequency electric
fields coupled into equipment are not covered by section 19 but has
been observed in reality.

Therefore Section 19 should be enhanced to cover
this kind of coupling.

Proposal Disposition:

     Accepted As Written

     
Accepted As Modified

       Withdrawn

         
Rejected

  

         
Other

Rejection Reason:

Proposal Deferred To:

        
RTCA SC-135 Concurrence

        
EUROCAE WG-14 Concurrence

Proposal Disposition By:

Date:

Revise From:

19.3.3 Electric Fields Induced Into Interconnecting
Cables

Subject the interconnecting wire bundle of the equipment
under test to an audio frequency electric field as illustrated by Figure
19-3. DETERMINE COMPLIANCE WITH APPLICABLE EQUIPMENT PERFORMANCE STANDARDS
when the field is of the value specified in Table 19-1.

During this test, all equipment interconnecting cables
shall be in accordance with the applicable installation and interface
control diagrams. Shielded or twisted wires shall be used only where
specified by the equipment manufacturer. Any inputs or outputs from
or to other equipment(s) normally associated with the equipment under
test shall be adequately simulated. The electric field power source
shall not be synchronized with the power source of the equipment power
supply. Frequency scan rates and dwell times shall be in accordance
with section 19.3.5

19.3.4 Spikes Induced Into Interconnecting Cables

During this test, all equipment interconnecting cables
shall be in accordance with the applicable installation and interface
control diagrams. Shielded or twisted wires shall be used only where
specified by the equipment manufacturer. Any inputs or outputs from
or to other equipment normally associated with the equipment under test
shall be adequately simulated.

Subject the interconnecting wire bundle of the equipment
under test to both positive and negative transient fields using the
test setup shown in Figure 19-4. Table 19-1 defines the desired cable
lengths for categories of section 19.2. The timer shown in Figure 19-4
shall be adjusted to yield a pulse repetition rate of eight to ten pulses
each second. The waveform present at point A, Figure 19-4, should be
similar to that described in Figure 19-5. For both positive and negative
polarities of the transient, the 

pulsing for each polarity shall be maintained for
a period of not less than two minutes or for a longer period of time
if specified in the relevant equipment specification.

After exposure, DETERMINE COMPLIANCE WITH APPLICABLE
EQUIPMENT PERFORMANCE STANDARDS. Any requirement for performance of
the equipment during application of the tests will be specified in the
equipment performance standard.

The inductive switching transient generated when
the contact opens should be very similar to the illustration in Figure
19-5, when monitored at point A on Figure 19-4. When the contact opens,
the voltage at Point A drives from +28 V dc to large negative voltages
in about two microseconds. (The capacitance, 250 to 3,000 picofarad
typically, between windings of the coil is charged negatively during
this time.) When the voltage reaches the ionizing potential, arc-over
occurs at the contact and the voltage drives rapidly toward 28 V dc
through the ionized path at the contact. The voltage at Point A usually
overshoots +28 V dc because of the wire inductance between Point A and
the coil. At this time, the arc extinguishes and the cycle is repeated.
In a typical case, the repetition period is 0.2 to 10 microseconds and
the number of repetitions is often 5 to 1,000 before the energy of the
inductive load (E = 1/2 LI 2) is dissipated.

19.3.5 Frequency Scan Rates

For test equipment that generate discrete frequencies,
the minimum number of test frequencies shall

TABLE 19-1 : APPLICABILITY OF CATEGORIES TO INDUCED
SIGNAL SUSCEPTIBILITY

Paragraph

Test

Category ZC

Category AC

Category BC

Category CC

19.3.1

Magnetic Fields induced into the equipment

20 A rms at 400 Hz

20 A rms at 400 Hz

20 A rms at 400 Hz

20 A rms at 400 Hz

19.3.2

Magnetic fields induced into interconnecting cables

IxL=30 A-m at 400 Hz reducing to 0.8 A-m at 15 kHz

IxL=18 A-m from 380 to 420 Hz

Not Applicable

IxL=120 A-m from 380 to 420 Hz and 60 A-m at 400 Hz reducing to 1.6
A-m at 15 kHz

19.3.3

Electric Fields induced into interconnecting cables

VxL=1800 V-m from 380 to 420 Hz

VxL=360 V-m from 380 to 420 Hz

Not Applicable

VxL=5400 V-m from 380 to 420 Hz and 5400 V-m at 400 Hz reducing to
135 V-m at 15 kHz

19.3.4

Spikes induced into interconnecting cables

Figure 19-4L=3.0 m

Figu