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3.3
MANUAL TRANSFER AND
START-UP
To transfer electrical loads to the Standby (EMER-
GENCY) power source side and start the engine man-
ually, refer to the Owner's Manual of the particular
transfer switch.
3.4
ENGINE GOVERNOR
ADJUSTMENTS
Engine speed governing is also controlled by the
engine control board. Connector J2 on the engine
control board interfaces with a governor driver mod-
ule and the Bosch throttle body. The engine governor
has been set by the factory during final testing of the
generator and, in most cases, should not be adjusted.
If, however, adjustments are necessary, or a new
engine control board is installed in the generator, the
following procedure should be followed (Figure 3.2):
1. Set all three potentiometers (pots) fully counter-
clockwise.
2. Under no load condition, increase the GAIN pot
as much as possible without causing instability.
3. Apply 1/4, 1/2, 3/4 and full load to the unit.
Decrease the GAIN pot if there is instability at any
load point.
4. Under full load condition, increase the stability
pot until the unit returns to 60 Hertz (or 50 Hertz
in 50 Hertz applications).
Figure 3.2 — Engine Governor Adjustment
U7
C4
C30
R49
U1
V .
R E
0 6
4 9
0 E
0 0
B #
P C
DIFFERENTIAL
STABILITY
14 Generac
®
Power Systems, Inc.
Section 3 — Operation
Guardian Liquid-cooled 27 kW and 30 kW Generators
R44
C27
Q2
C9
C26
D10
C21
C2
RL1
RL2
R1
R48
D17
L3
D19
DIP SWITCH
1
POSITION 1
POSITION 2
UNUSED
50/60 HZ
GTS/ATS Select
3
ON = 50 HZ
ON = GTS
2
GTS/ATS
OFF = ATS (standard mode)
OFF = 60 HZ
4
50/60 HZ
5. Reduce load to 3/4, 1/2, 1/4 and no load.
Decrease the stability pot if there is instability at
any load point.
6. Adjust differential pot to make the recovery to
load changes even faster and minimize load
change undershoot and overshoot. If it is set too
high it may introduce oscillations at some load. It
can be set to zero (full CCW) if a small amount
causes oscillations at some load.
3.5
RETRANSFER AND SHUTDOWN
When utility power source voltage has been restored,
electrical loads may be transferred back to that
source and the generator can be shut down as fol-
lows:
• Verify that UTILITY power supply voltage to the
transfer switch has been positively turned OFF,
using whatever means provided (such as utility
main line circuit breaker).
• Set the generator's main circuit breaker to its OFF
or OPEN position.
• Let the generator engine run at no-load for a few
minutes, to stabilize internal unit temperatures.
• On the generator console, set the AUTO/OFF/
MANUAL switch to OFF. Wait for engine to come to
a complete stop.
• For transfer to utility position, refer to the Owner's
Manual of the particular transfer switch.
• Turn on the UTILITY power supply to the transfer
switch, using whatever means provided (such as a
utility main line circuit breaker). The UTILITY
power source now powers the loads.
3.6
AUTOMATIC OPERATION
To set the system for fully automatic operation, pro-
J2
ceed as follows:
• Check that load circuits are connected to the
utility power supply.
• Set the AUTO/OFF/MANUAL switch to its AUTO
position.
• Set the generator main circuit breaker to its ON or
CLOSED position.
3.7
WEEKLY EXERCISE CYCLE
The engine control board will start and run the gen-
erator once every seven days for approximately 12
minutes. If utility should fail during this exercise
period, the engine control board will transfer the load
J1
to the generator output and continue to run until util-
ity returns.
On the day, and at the time of day chosen for the gen-
erator to exercise, set the weekly exercise cycle as fol-
lows:
1. Place the AUTO/OFF/MANUAL switch in the
AUTO position.
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