Power Supply Function
• The internal resistance of an alternator, in the case of load dump, is mainly a
function of alternator rotational speed and excitation current.
• The internal resistance, Ri, of the load dump test pulse generator shall be
obtained from the following relationship.
– U
nom
: The specified voltage of the alternator
– I
rated
: The specified current at an alternator speed of 6000r/min
– N
act
: The actual alternator speed, unit: round per minute (r/min)
• The pulse is determined by the peak voltage U
n
, the clamping voltage U
S
,
the internal resistance R
i
, and the pulse duration t
d
; in all cases small values
of U
n
are correlated with small values of R
i
and t
d
, and high values of U
n
with
high values of R
i
and t
d
. For the test voltage U
A
please refer to ISO16750-1.
How to recall this waveform from menu (take Test A 12V as an example):
1. Press the composite keys [Shift]+[I-set] (Function) on the front panel to en-
ter the function menu.
2. Use the knob or press the Up/Down key to select 3.Road-Vehicles = Off
and press [Enter].
3. Press the Left/Right key to select ISO16750-2 and press [Enter] to confirm.
4. Press the Left/Right key to select Load-Dump, and press [Enter] to confirm.
5. Press the Left/Right key to select Test A, and press [Enter] to confirm.
6. Press the Left/Right key to select 12V, and press [Enter] to confirm.
7. Set the Td and Un in turns, and press [Enter] to confirm.
The interface returns to the main interface of the system and displays
LOAD-DUMP.
8. Press [On/Off] on the front panel to turn on the output.
9. According to the selected trigger method (same as the trigger method of the
LIST function), for example, press [Shift]+[On/Off](Trigger) to trigger the
output of the waveform.
4.6.3.3 42V Road Vehicles — Electrical and Electronic Equipment for
a Supply Voltage of 42 V — Electrical loads
A test wave completely conforming to International Standard ISO21848 is built
inside the device, which can be used for the test of Electrical and electronic
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