The digital voltage regulator (DVR) is a
microprocessor-based voltage regulator. The
parameters are preset at the factory or the
parameters can be modified in order to meet the
specific requirements on the site. Certain system
parameters can also be monitored on the display (1)
of the DVR. Keypad (5) is used to change the
information that is shown on the display. J1
connector (6) is used to join the DVR to a personal
computer. Screw terminals (7) are used to join the
DVR to the generator and various customer options.
Adjustment Procedure for the
Voltage Regulators
VR3F
Note: The VR3F regulator is protected by a fuse(s).
The VR3F regulator also has a solid-state
overcurrent protection. If a fuse becomes open,
contact a Caterpillar dealer.
1. Remove the access panel of the generator.
2. Loosen the locknut on the voltage droop
potentiometer (1). Remove the protective screw
from the voltage level potentiometer (2).
3. Turn voltage droop potentiometer (1)
counterclockwise to zero droop. Tighten the
locknut. Voltage droop potentiometer (1) is located
next to the regulator.
4. Perform required maintenance on the engine
before you start the engine.
5. Start the engine. Allow the engine to warm up.
Refer to the Safety Section, “Engine Starting”.
6. Increase engine speed to full governed rated
speed (high idle).
7. Observe the voltmeter reading. If the desired
voltage is not indicated, set the no-load voltage
with the voltage level potentiometer (2) or the
voltage adjust rheostat. The voltage adjust
rheostat is located on the control panel.
8. Close the load circuit breaker. Apply full load
gradually. Adjust the governor control until the
nameplate frequency is on the frequency meter or
until the rated speed is displayed on the
tachometer. The unit of measurement for
frequency is Hertz. The unit of measurement for
the rated speed is RPM.
9. Remove the load. If necessary, adjust the voltage
level potentiometer (2) in order to obtain the
desired voltage.
10. Apply the load. Observe the voltmeter reading.
Repeat Steps 8 and 9 until the voltage at no load
equals the voltage at full load.
11. Tighten the locknuts. Install the protective screws
on the respective potentiometers. Install the
access panel of the generator. STOP.
Digital Voltage Regulator (DVR)
Refer to the Specifications, Systems Operation,
Testing and Adjusting, SENR5833, “Digital Voltage
Regulator”.
The digital voltage regulator (DVR) can be set up for
a specific application by using the configured
parameters. Parameters are preset at the factory.
Parameters may need adjustment in order to meet
the specific requirements of a site. The DVR also
detects faults. When a fault is detected, the DVR sets
the appropriate alarm or caution. Certain system
parameters can also be monitored on the display of
the DVR.
Display (1) and keypad (5) are used to select
parameter values. The display and the keypad are
also used to manipulate the parameter values that
control the operation of the digital voltage regulator.
The display of the digital voltage regulator has four
digits. When one of these digits is a colon, the
number that is showing is a parameter code. When a
colon is not present, the number that is showing is a
parameter value. A decimal point in the display is
used to indicate the precision of the parameter value.
Keypad (5) has three keys. The keys are listed below.
• Function key (2)
• Scroll down key (3)
• Scroll up key (4)
Display (1) has two modes. These modes are the
parameter code mode and the parameter value
mode. Function key (2) is used to toggle back and
forth between the two modes. Scroll down key (3)
and scroll up key (4) are used to change the value of
the parameters on the display. The scroll down key
will decrease the parameter number or the scroll
down key will decrease the value. The scroll up key
will increase the parameter number or the scroll up
key will increase the value.
Table 4
Parameter Code Parameter Value
:01 0480
0481
0482
0483
(continued)
78
SEBU7125-13
Operation Section
Voltage Regulators
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