Control Of Voltage And Frequency; Bl4-U Avr Settings - Sincro HB Série Manuel D'utilisation Et De Maintenance

All changes in connection must be carried
out solely by a qualifi ed specialist.
WARNING!
6.4.4 BL4-U AVR
The various generator parameters are
factory set before testing: so no further
adjustments on the machine should be
necessary; in the event that the covers
WARNING!
need to be removed for the adjustments
and live electrical con tacts are left bare, it
is important that this operation be carried
out solely by qualifi ed specialists in
electrical plant maintenance.
The AVR controls the generator voltage. The AVR is
used to keep a constant voltage when the load and
machine parameters vary.
The AVR requires a so-called sensing connection; a
power supply from a specific circuit (AUX); an output to
the exciter (+/-). In case of unbalanced or distorted load,
voltage regulation accuracy could be reduced.
A frequency control progressively reduces the generator
excitation when the drive engine speed drops below a
pre-set, adjustable threshold preventing over-excitation
at low operating speeds and abating the load engage
effects on the engine.
The BL4-U AVR has two dip-switches: switch 1 for
the frequency setting and switch 2 for remote voltage
regulation. Set switch 1 to "ON" for 50Hz working, to
"OFF" for 60Hz working. Set switch 2 to "Std" for working
without remote voltage regulation, to "Ext" position for
working with remote voltage regulation.
The output voltage can be changed by adjusting
potentiometer "V". Run 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 speed protection should first be
calibrated.
The voltage sensing jumper should be connected:
• to terminals "115" and "0", if connected to a voltage
between 100 and 130V
• to terminals "230" and "0", if connected to a voltage
between 185 and 245V.
• to terminals "400" and "0", if connected to a voltage
between 340 and 480V.
If the voltage is set any higher than its
maximum limit the gen er a tor may be
damaged.
WARNING!
Stability adjustment: if on load voltage fluctuations
are experienced adjust potentiometer "ST", which
modulates the reaction time of the regulator to external
inputs, there by eliminating any instability in the
alternator-load system.
If the under speed is set at too low
a frequency, the generator may be
damaged. On the other hand, too high a
frequency can cause voltage drops with
WARNING!
high loads.
Setting of the under speed protection at 50 (60)
Hz: start up rotation of the gen er at ing set adjusting it to
obtain a frequency of 46 (56)Hz. Turn trimmer "UF" until
the voltage begins to drop. Restore nominal speed.
Remote voltage adjustment :
1) with potentiometer: wire the potentiometer
(5kOhm, 3W) to the terminals "EXT POT". Run the
generating set to its nominal speed and adjust the
external potentiometer and eventually also the trimmer
"V" to obtain the required voltage.
2) Connection with controller or cosf regulator: the
AVR regulator accepts voltage analogic input (0-5VDC,
observe polarity shown in figure) for remote voltage
adjustment. To set the system, follow this procedure:
- Decrease the voltage by turning the "V" trimmer
counter-clockwise;
- Apply half the control voltage at the "EXT pot" terminals
(2,5 VDC);
- Act on the "V" trimmer to bring the voltage to the
nominal value;
in this way, the external controller can increase or
decrease the output voltage.
Voltage V
Sensing
Voltage
increasing
Voltage
decreasing
Underfrequency
protection limit
increasing
Underfrequency
protection limit
decreasing
Stability ST
Underspeed protection UF
switch 2
switch 1
BL4-U
Supply
Stator Excitator
Stability
decreasing
Stability
increasing
Connection with controller,
Observe polarity:
23