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 qualified 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 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 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.
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 high loads.
WARNING!
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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