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RTCA SC-135 and EUROCAE WG-14
Change Proposal Form
(One major comment per form.
Shaded blocks for committee use only.)
SC-135 Paper Number:
Date:
DO-160E Section:
Rev F #054H
October 11, 05
16
Author’s Name, Affiliation, and E-mail:
Paragraph:
Page:
C. Bertran EUROCAE
16.7.3
Reason for Change:
Requirement in addition to the one related to AC voltage modulation (§ 16.5.1.2) and derived from last
issue of ISO1540. Regarding limit of line current modulation, the limit is set to 10% (instead of 15%)
issued from our experience.
Proposal Disposition:
X
Accepted As Written
Withdrawn
Accepted As Modified
Rejected
Other
Rejection Reason:
Proposal Deferred To:
Note: The goal is not to capture infrequent current changes from changes in operating modes (actuated
or non-actuated.) but to look for unstable and poorly filtered systems
RTCA SC-135 Concurrence
Proposal Disposition By:
EUROCAE WG-14 Concurrence
Date:
Revise From:
New paragraph
Proposal Page Number:
1 of 3
SC-135 Change Proposal Form Rev C
Revise To:
16.2 Current Modulation Control Tests: Test Designation L
This test designation relates to equipment where the current ripple (or current modulation) drawn
from the power source is controlled. Equipment that meets the requirements of this test
designation is to be marked with test designation L. Equipment that does not meet the
requirements of this category is to be tested and marked with test designation Z (other test
criterion.)
---------------------------------------------------------16.7.3 Current Modulation in Steady-State Operation (ac)
16.7.3.1 Definition
The following requirements shall be met for equipment with test designation L (as defined in
section 16.2) Equipment that meets an alternate test condition is to be marked with designation
Z.
Current Modulation is the cyclic variation, random variation, or both, about the mean level of the
ac peak current that may occur during steady-state equipment operation.
Any equipment which load current may modulate is potentially contributing to ac voltage
modulation. Test designation L is intended for equipment with a maximum power consumption
greater than 35 VA or a maximum total power consumption of all similar equipment type on
airplane greater than 150 VA.
16.7.3.2 Requirement
Operate the equipment in the mode that draws minimum and maximum steady-state current
from the electrical power source used for this test, with a voltage of 115 Vrms ± 1 Vrms (see
note 1 below) at its terminals and a frequency as specified in the note 2 below. If the difference
between maximum and minimum steady state current is less than 25% of the maximum steady
state current, only the maximum steady state current needs to be tested
. After the equipment has stabilized, at any time the value of the equipment line current
modulation shall not exceed 0.28 peak to valley times the RMS value of the equipment
maximum steady-state current for equipment of the same type < 1 kVA and 0.14 peak to valley
times the RMS value for equipment maximum steady-state current >= 1 kVA.. The load current
is to be tested over at least three 500 msec long sweeps.
Notes:
1.
The AC source used to supply the EUT shall be such as the RMS value of the voltage
modulation is equal or less than 420 mVpeak to valley, whatever the modulation frequency
between 1 Hz and higher of 200 Hz and one half the fundamental line frequency, when this
AC source supplies a resistive load drawing a current equal to the EUT maximum steadystate current.
2.
This test shall be performed with a frequency of:

400 +5/-0 Hz for A(CF) category equipment

360 +5/-0 Hz for variable frequency equipment then repeated with 650 +5/-0 Hz for
A(NF) category equipment and 800 +5/-0 Hz for A(WF) category equipment.
3 The following load demand variations are exempt from this requirement:

Initial start-up
Proposal Page Number:
2 of 3
SC-135 Change Proposal Form Rev C

Operating mode changes.

Responses to changes in input voltage and frequency.

Final shut-down.
4. This test is not intended to monitor current changes above the fundamental line frequency.
5. The current probe shall be dc coupled.
As Modified Text:
Related action items:
Update figure 16-1 to extend table out from 200 Hz to 1/2 the line frequency.
Update verbiage in section 16.2 as necessary to add text for designation L
Paul's notes:
1 TBC is the same as TBD.
2. Add this test as its own letter designation to allow modulated loads to modulate.
3.Will this requirement be interpreted consistently between different avionics such as transponders, HF
Coms, Microwave Ovens (10% heat setting) and actuators?
5. di/dt of operating mode changes is not intended to be controlled by this proposal.
Proposal Page Number:
3 of 3
SC-135 Change Proposal Form Rev C