Control Of Voltage And Frequency; Bl4-U Avr Settings - Sincro SK160 Serie Manual De Uso

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 contacts are left bare, it
is important that this operation be carried
out solely by qualified 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 for the frequency
setting. Set both switches to "ON" for 50Hz operation.
Set both switches to "off" for 60Hz operation.
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 generator 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, thereby eliminating any instability in the
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.
alternator-load system.
Setting of the under speed protection 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.
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
Underspeed protection UF
Stator Excitator
Sensing
Voltage
increasing
Voltage
decreasing
Underfrequency
protection limit
increasing
Underfrequency
protection limit
decreasing
Stability ST
Frequency dip switch
BL4-U
Supply
Stability
decreasing
Stability
increasing
Connection with controller,
Observe polarity:
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