Dbc1 Avr Settings - Sincro DC Serie Manual De Uso Y Mantenimiento

6.4.3 DBC1 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 controller has a jumper to set the frequency. Set the
jumper "Jumper Frequency" of the AVR board, in function
of the operating frequency.
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 sensing voltage (+ Batt. - Batt.) must be connected to
the + and - terminals of the bridge rectifier. Observe the
polarity.
The jumper voltage is already set in the
factory according to the internal connection
of the generator. You can NOT change the
output voltage by moving the voltage jumper.
WARNING!
The sensing of current from the TA must be connected to
the terminals TA and Com / TA. The potentiometer "I" is used
to set the limit of maximum current from the generator DC.
If the voltage, or current, are set any higher
than its maximum limit the generator may be
damaged.
CAUTION!
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 "POT V" and "Com/TA". 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 (0-3VDC,
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 "POT V" and "Com/
TA" terminals (1,5 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
corrente
Voltage
(TA)
Sensing
Voltage
increasing
Voltage
decreasing
Underfrequency
protection limit
increasing
Underfrequency
protection limit
decreasing
Current I
Underspeed protection UF
Stability ST
Voltage jumper
Frequency jumper
DBC1
Supply
Stator Excitator
Stability
decreasing
Stability
increasing
Current
increasing
Current
decreasing
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