Soga sincro FB4 BT, Use And Maintenance Manual

Page: 23 / 36

FB BT - Giugno 2009 - Rev. 00 - 23
Caution! Unhook the AVR voltage regulator before carrying out
this test.
The results must be over 2MOhm. If this is not the case, the alternator
alone should be oven dried at 60 ÷ 80°C for 3 hours. Before carrying out
this op er a tion remove the voltage regulator. As an alternative to oven
dry ing hot air at 60 ÷ 80°C can be blown through the alternator for at
least 1 hour.
Important! The windings are tested under high tension during pro-
duc tion. Additional high tension tests can weaken the insulation
there by reducing the working lifespan. If a high tension test should
prove necessary for cus tom er approval, these tests should be car-
ried out at lower voltages.
6.4.2 Control of voltage and frequency
Control that the voltage and frequency levels required by the electricity
generating set correspond to the generator data plate.
6.4.3 AVR board settings
To select the AVR settings access the control board after removing the
cover. Most adjustments are factory set to ensure satisfactory results in
the operating tests on commissioning. Further adjustments may be nece-
essary to ensure optimum operation under specifi c working conditions.
The fi gure alongside shows the position of the jumpers, one jumper
(Frequency) refers to the operation of the alternator at 50 or 60Hz.
The output voltage can be changed by adjusting trimmer
"V ”. Take the
generating set to its nominal speed and turn until the required voltage is
obtained. If a small variation in speed causes a change in voltage, then
the Under Fequency protection should fi rst be calibrated.
The voltage reference should be connected:
• at terminal “ V
b+
” (red wire) and “ V
b-
” (black wire) the output of three-
phase bridge rectifi er (reference n°32, paragraph 12.1).
With the jumper on 48 V (fi gure alongside), the trimmer “ V ” changes
the voltage between 45 to 58 V.
The current reference should be connected:
• at terminal “ I
b+
” (red wire) and “ I
b-
” (black wire) the output of current
transformer CT (reference n°39, paragraph 12.1).
The trimmer “ I ” changes the voltage between 50 to 250 A.
Caution: if the voltage and current are set any higher than their
maximum limit the generator may be damaged.
Setting the bottom speed at 50 (60)Hz : start up rotation of the
generating set adjusting it to obtain a frequency of 46 (56)Hz. Turn
trimmer “
UF ” until the voltage begins to drop. Restore nominal speed.
Caution: if the bottom speed is set at too low a frequency the gen-
erator may be damaged. On the other hand, too high a frequency
can cause voltage drops with high loads.
Connecting an external potentiometer (5kOhm) : remove the
jumper on terminals “ EXT POT ” and wire the potentiometer to the free
terminals, however make sure that it is set at its maximum resistance.
Turn trimmer “
I ” clockwise to its limit (minimal resistance). Take the
generating set to its nominal speed, applied a load and adjust the
Important!
The windings are tested under high ten-
sion during pro duc tion. Additional high
tension tests can weaken the insulation
there by reducing the working lifespan.
If a high tension test should prove neces-
sary for cus tom er approval, these tests
should be car ried out at lower voltages.
Caution!
Unhook the AVR voltage regulator before
carrying out this test.
ENGLISH
Caution!
If the voltage is set any higher than its
maximum limit the gen er a tor may be
damaged.
Caution!
If the bottom speed is set at too low a
frequency the gen er a tor may be damaged.
On the other hand, too high a frequency
can cause voltage drops with high loads.