3.2.3 15 AMP FUSE
Fuse protects the control console's DC control circuit
against electrical overload. If the fuse has melted
open because of an overload, engine cranking and
startup cannot occur. If the fuse needs to be replaced,
use only an identical 15-amp replacement fuse. (Type
3.2.4 4.0 AMP INLINE FUSE
This fuse protects the battery charger against electri-
cal overload. If the fuse needs to be replaced, use only
an identical 4 amp replacement fuse (type AG).
This fuse will not remove the + battery input
power from the PCB when it opens. This means
the exercise timer will not be reset.
3.2.5 SET EXERCISE TIME SWITCH
This switch allows programming the generator to
start and exercise automatically. "See Weekly
3.2.6 SYSTEM READY LED
The System Ready LED (green) has two main pro-
poses. First, the LED will be ON when the
AUTO/OFF/MANUAL switch is in the AUTO position,
UTILITY is present, and there are no system alarms.
This ON state indicates the system is fully ready for
The system ready LED will be OFF when the switch
is in the MANUAL or OFF positions.
The system ready LED is also used to indicate the
presence of UTILITY sensing at the PCB when the
switch is either in the AUTO or MANUAL modes. The
LED will flash at the rate of 1/2 second on, 1/2 sec-
ond off if the UTILITY sensing level is below the
transfer back threshold.
This secondary function is only available with dip
switch two in the OFF position (engineered transfer
MANUAL TRANSFER AND
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
Power Systems, Inc.
Section 3 — Operation
Guardian 40kW Liquid-cooled Generators
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-
2. Under no load condition, increase the GAIN pot
as much as possible without causeing 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
4. Under full load condition, increase the stability
pot until the unit returns to 60 Hertz (or 50 Hertz
in 50 Hertz applications).
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.
Figure 3.2 — Engine Governor Adjustment
ON = 50 HZ
ON = GTS
OFF = ATS (standard mode)
OFF = 60 HZ