ITech IT6600C Series User Manual page 78

Parameter
12V
79≤Us≤101
a
Us (V)
Us*(V) It is fixed at 35V
here and cannot be
set.
(Ω) 0.5≤Ri≤4
a
Ri
40≤t ≤400
t (ms)
d d
t (ms) -
r
Note: a
If not otherwise agreed, use the upper voltage level with the upper
value for internal resistance or use the lower voltage level with the lower value
for internal resistance.

t: Time

U: Test voltage

t : Duration of pulse
d

t : Rising Slope
r

U : The supply voltage of the generator in operation: U
A
system, U =28V in the 24V system. (see ISO 16750-1)
A

U : Peak voltage
S

U *: Supply voltage with load dump suppression (i.e. clamping voltage)
S
The following general considerations of the dynamic behavior of alternators
during load dump apply:

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 : The specified voltage of the alternator.
nom

I : The specified current at an alternator speed of 6000r/min.
rated

N : The actual alternator speed, unit: round per minute (r/min).
act

The pulse is determined by the peak voltage U
the internal resistance Ri, and the pulse duration t
of U are correlated with small values of Ri and t
n
high values of Ri and t
1.
How to recall this waveform from menu (take Test A 12V as an example):
1. Click Vehicle on the Menu screen to enter the vehicle test screen.
1) Press the up/down key to move the cursor to the Standards function
setting and press the [Enter] key to confirm. Rotate the knob to select
ISO16750-2 and press the [Enter] key to confirm.
2) Press the up/down key to move the cursor to the Mode function setting
and press the [Enter] key to confirm. Rotate the knob to select Load-
Dump and press the [Enter] key to confirm.
3) Press the up/down key to move the cursor to the Voltage Range
function setting and press the [Enter] key to confirm. Press the numeric
Copyright ©ITECH Electronic Co., Ltd.
Type of system
24V
151≤Us≤202
As specified by
customer (typical
value 58).
1≤Ri≤8
100≤t ≤350
d
-
. For the test voltage U
d
Power Supply Function
Minimum test
requirements
5 pulses at 1
minute intervals.
=14V in the 12V
A
, the clamping voltage U
n
; in all cases small values
d
, and high values of U
d n
please refer to ISO16750-
A
,
S
with
69