DAF LF45, LF55 Series. Manual — part 340
5
LF45/55 series
Description of components
COMPONENTS
2-5
Connection 15
When the contact has been turned on, power is
supplied to the alternator via connection 15,
pin 3 (1010). The regulator uses this power to
activate pre-excitation (self-energising). If there
is an open circuit in this connection, the
alternator will not produce any power until it
reaches a speed of about 5000 rpm. This
corresponds to an engine speed of approx.
1500 rpm. The alternator will energise itself
when it reaches this speed.
Sens connection
The sens connection, pin 4, can be used to
compensate for voltage losses in B+.
There are voltage differences between the
alternator and the battery.
Voltage regulation can be improved if these
voltage variations can be controlled.
This function is, however, not used. The
sens connection is connected directly to B+2
and therefore no voltage differences are
measured.
L connection
The L connection, pin 2, is connected to the VIC
electronic unit.
This connection is used to activate a fault
message in the main display via the VIC, if
necessary.
L voltage high: no fault
L voltage low: fault
The following faults can be detected via the
“L”-connection:
-
voltage too low (< 16 V)
-
open circuit in connection 15 (1010)
-
open circuit in “S” connection - open circuit
in “L” connection
These faults are indicated by the yellow
“Alternator fault” warning.
Too high a voltage (red warning) can be
recognised by too high a voltage (>31 V) on the
VIC electronic unit.
E501129
L
15
S
2
200440
5
COMPONENTS
Description of components
LF45/55 series
2-6
2.6 WINDSCREEN HEATING RELAY
The windscreen heating relay (2) is a time relay
with a duration of 12 minutes. The relay is
activated by the mirror heating switch (1). This
activates the timer (4) in the relay. The timer in
its turn activates the internal relay (5), thus
supplying the windscreen heating system (3)
with power.
E501512
1
5
4
3
2
30
87
85
86
+24V
A.
After 12 minutes the timer automatically
switches off the internal relay, although the
switch continues to be operated.
B.
If the switch is turned off before the 12
minutes have passed, the relay is still
switched on for 12 minutes.
C.
If the switch is turned on and off twice in
succession within the twelve minutes, the
timer will turn off the relay.
E501513
A
B
C
30
85
87
t
t
t
t >12mn
t <12mn
t <12mn
t =12mn
t =12mn
2
200440
5
LF45/55 series
Diagnostics
COMPONENTS
3-1
3. DIAGNOSTICS
3.1 DIAGNOSTICS IN ELECTRICAL SYSTEMS
For diagnosis, DAVIE XD is used.
This tool has a two-channel scope and a
multimeter function.
DAVIE XD is also used to read data from
electronic systems. When a fault arises, it offers
the option of selecting a “guided” diagnosis that
goes through a series of measurement steps to
help locate the cause of the problem.
Refer to the user manual for an extensive
description of the operation and possibilities of
DAVIE XD.
2
200440
5
COMPONENTS
Diagnostics
LF45/55 series
3-2
2
200440
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