ITech IT-M3900B Series User Manual page 99

Inside most novel alternator, the amplitude of load dump is decreased by in-
creasing the limiter diode (clamping diode). The load dump may be caused by
cable corrosion, poor cable contact or disconnecting the battery intentionly
when the engine is running.
The pulse shape and parameters for an alternator without centralized load
dump suppression (Test A) are given in follow.
•
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
Parameter
U S a (V)
79≤U
Ri a (Ω)
0.5≤Ri≤4
t (ms)
40≤t
d
t (ms)
–
r
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 in-
ternal resistance.
Copyright © Itech Electronic Co., Ltd.
Type of system
12V 24V
≤101 151≤U
S S
1≤Ri≤8
≤400 100≤t
d d
–
Power Supply Function
= 14V in the 12V
A
Minimum test
requirements
≤202
10 pulses at 1 min intervals
≤350
87