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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-160G Section: 16
Rev G #087
March 17th 09
Author’s Name, Affiliation, and E-mail:
Paragraph:
Page:
Evelyn Matheson, Boeing
16.7.6.2
16-40
Reason for Change:
Existing requirement calls out test to be performed at minimum and maximum operating currents.
However, it makes more sense to specify a test operating mode where the equipment has its
highest input current modulation – and this may or may not occur at the minimum and/or
maximum current demand.
Proposal Disposition:
X
Accepted As Written
Withdrawn
Accepted As Modified
Rejected
Other
Rejection Reason:
Proposal Deferred To:
X
RTCA SC-135 Concurrence
Proposal Disposition By:
EUROCAE WG-14 Concurrence
Date:
Revise From:
16.7.6.2
Operate the equipment in the mode that draws minimum and maximum steadystate current from the electrical power source used for this test, with a voltage of
115 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 operating mode 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 that the RMS value of the
voltage modulation is equal to or less than 420 mV peak to valley, whatever the
modulation frequency is between 1 Hz and the higher of 200 Hz and one half the
fundamental line frequency, when this AC source supplies a resistive load drawing a
Proposal Page Number:
1 of 2
SC-135 Change Proposal Form Rev G
current equal to the EUT maximum steady-state current.
2.
3.
This test shall be performed with a frequency of:

400 +5/-5 Hz for A(CF) category equipment

360 +5/-0 Hz for variable frequency equipment then repeated with 650 +0/-5 Hz
for A(NF) category equipment and 800 +0/-5 Hz for A(WF) category equipment.
The following load demand variations are exempt from this requirement:

Initial start-up

Transition between operating modes.

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
Revise To:
Operate the equipment in the mode as determined by the equipment manufacture that draws the
maximum amount of input current modulation (i.e. the greatest variation of input peak to valley
current as measured within a 500msec window.) from the electrical power sourceand with a
voltage of 115 Vrms (see note 1 below) at its terminals and a frequency as specified in the note 2
below. If the equipment’s input current modulation does not vary with operating mode, operate the
equipment in the mode that draws maximum steady state current.
Note 6. If the equipment under test supplies other loads, those downstream loads should be either
connected during the test or simulated in a manner that represents simliar modulation
characteristics.
Rationale:
Existing requirement calls out test to be performed at minimum and maximum operating currents.
However, it makes more sense to specify a test operating mode where the equipment has its
highest input current modulation – and this may or may not occur at the minimum and/or
maximum current demand.
Proposal Page Number:
2 of 2
SC-135 Change Proposal Form Rev G