TD - As480 Avr - 04.08 - 02 - GB
TD - As480 Avr - 04.08 - 02 - GB
TD - As480 Avr - 04.08 - 02 - GB
REGULATOR (AVR)
SPECIFICATION INSTALLATION AND ADJUSTMENTS
General description
Technical specification
The AVR is linked with the main stator windings and the exciter
field windings to provide closed loop control of the output voltage
with load regulation of +/- 1.0%. The AVR voltage sensing
terminals continuously sample the output windings for voltage
control purposes. In response to this sample voltage, the AVR
controls the power fed to the exciter field, and hence the main
field, to maintain the machine output voltage within the specified
limits, compensating for load, speed, temperature and power
factor of the generator.
Positive voltage build up from residual levels is ensured by the
use of efficient semiconductors in the power circuitry of the AVR.
A frequency measuring circuit continually monitors the
generator output frequency and provides under-speed protection
of the excitation system. This is done by reducing the output
voltage proportionally with speed below a pre-settable threshold.
A manual adjustment is provided for factory setting of the under
frequency roll off point, (UFRO). This can be changed to 60Hz
(or 50Hz) in the field by push-on link selection.
A wide range of stability settings are available to compensate for
machine sizes and applications. A slow setting is available for
applications involving single/twin cylinder engines and where
lamp-flicker could be a problem.
Provision is made for the connection of a remote voltage
trimmer, allowing the user fine control of the generators output
voltage.
Operation with 110Vac sensing is possible, replace the hand
trimmer link with fixed resistor. The hand trimmer option cannot
be used in this configuration. The generator overload capability
is reduced in 110V operation.
The AVR has the facility for droop CT connection, to allow
parallel running with other similarly equipped generators.
Over excitation conditions are limited to a safe period by a
protection circuit within the AVR. Once activated by a sustained
over-excitation condition, the generator voltage is reduced to a
low level until reset. Stopping the generator or removing power
from the AVR will perform the necessary reset.
Connections are provided to interface to the optional Excitation
Boost System. This incorporates a small externally mounted
rotary power supply which provides excitation power in the event
of heavy overloads or short circuits. The EBS is short term rated
and responds to signals from the AVR to deliver excitation power
when required. A separate overload protection system within the
EBS electronic module protects the generator against sustained
overloads.
Cummins 2008
OUTPUT
Voltage
Voltage
Current
Resistance
REGULATION
+/- 1.0% (see note 2)
THERMAL DRIFT
0.03% per deg. C change in AVR ambient (see note 3)
TYPICAL SYSTEM RESPONSE
AVR response
Field current to 90%
Machine Volts to 97%
20ms
80 ms
300ms
20-100 Hz
100Hz 2kHz
Operating temperature
Relative Humidity 0-70C
Storage temperature
50mm/sec
3.3g
-40 to +70C (note 6)
95% (note 7)
-55 to +80C
NOTES
1. De-rate by 20% if mounted external to generator.
2. Inclusive of 4% engine governing.
3. After 2 minutes warm-up.
4. Generator de-rate may apply. Check with factory.
5. Factory set, semi-sealed, jumper selectable.
6. De-rate output current by 5% per deg. C above 60C.
7. Non condensing.
TD_AS480 AVR_04.08_02_GB
Cummins 2008
TD_AS480 AVR_04.08_02_GB
Stability Linking
> 100kW
< 100kW
Slow
Link BD
Hand
Trimmer
(optional)
Raise
VOLTS
< 100kW
Fast
1k / 1W
2
1
S2
S1
DROOP
Link BC
F1
DR
EB
F2
F2
connections for
excitation boost
unit
F1
No Link
STABILITY
D
C
B
50
HZ
60
50Hz 60Hz
UFRO Linking
Control
Droop
C/T
(optional)
UFRO
Remove link
before fitting
LED
Function
Direction
VOLTS
STABILITY
DROOP
UFRO
Cummins 2008
TD_AS480 AVR_04.08_02_GB
UNDER-FREQUENCY-ROLL-OFF ADJUSTMENT:
(UFRO)
Cummins 2008
TD_AS480 AVR_04.08_02_GB
Cummins 2008
As this support is
TD_AS480 AVR_04.08_02_GB
POWER INPUT
Voltage
Frequency
100-120 Hz nominal
time-constants.
OUTPUT
Voltage
Current
continuous 6A
Resistance
15 ohms min
20ms
INTERNAL TIMERS
Start-up timer
5sec nominal
5sec nominal
TD_AS480 AVR_04.08_02_GB