2018.01 / g
Electric Power Generation
22
Installation and maintenance
R449 revision f
AVRs
3983 en -
5 - TROUBLESHOOTING
5.1 - Checking the windings and
rotating diodes using a separate
excitation
During this procedure, you must check that
the alternator is not connected to any
external loads and examine the terminal box
to check that the connections have been
made correctly.
- Stop the generator, disconnect and isolate
the regulator wires.
- There are two possible assemblies for a
separate excitation: see the diagrams
below.
- Assembly A: Connect the DC supply (2
batteries in series) in series with a rheostat
of approximately 20 ohms/500W and a
diode on both field winding wires (5+) (6-).
6 -
5 +
Diode 5 A
Battery 12V
Rh. 20 - 500 W
-
+
ASSEMBLY A
Exciter field
- Assembly B: Connect a «variac» variable
power supply and a diode bridge to both
field winding wires (5+) (6-).
- These two systems must be compatible
with the excitation rating of the machine
(see the nameplate).
- Run the generator set at its nominal speed.
- Gradually increase the power supply
current of the field winding by adjusting the
rheostat or variac and measure output
voltages L1, L2, L3, checking the no-load
excitation voltages and currents. (See the
alternator nameplate or ask factory for the
test log).
- If the output voltages are at their rated
values and are balanced at < 1% for the
given excitation value, the machine is
operating correctly and the fault is due to the
regulation part (regulator, wiring, sensing,
auxiliary windings).
When the alternator is stopped, mains
voltage may still be present at the module
voltage sensing terminals.
Do not perform dielectric tests without
disconnecting the module and
associated AVR.
RISK OF DESTRUCTION
-
+
6 -
5 +
Variac
AC
220 V
Diode
5A
50
60
70
80
90
100
40
30
20
10
0
ASSEMBLY B
Exciter field
5.2 - Static checking of the regulator
If the regulator operates correctly during a
static test, this does not necessarily mean
that it will operate correctly under real
conditions.
If the regulator fails the static test, it can be
concluded without doubt that the regulator is
faulty.
Connect a test bulb in accordance with the
diagram.
The power supply voltage must be between
200 and 240V. The voltage of the bulb is
230V. The power of the bulb will be less than
100W.
- Turn potentiometer P2 fully anti-clockwise.
- Switch the regulator on; the bulb must
briefly light up and then go out.
- Slowly turn the voltage potentiometer
clockwise, to the right.
- When turned fully clockwise, the bulb lights
up continuously.
- At the regulation point, turning the voltage
adjustment potentiometer slightly in one
direction or the other should make the bulb
light up or go out. If the bulb is either lit
continuously or does not light up at all, the
regulator is faulty.
