Electronic Governor (Optional) - Westerbeke 11.5KW-60Hz Service Manual

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ELECTRONIC GOVERNOR
(OPTIONAL)
ACTUATOR (ELECTRONIC GOVERNING)
The
BCU (Electronic Control Unit) in the control box on the
generator controls the engine speed electronically. The ECU
senses engine speed from a signal sent to it from a MPU
(Magnetic Pick Up) positioned on the flywheel bellhousing
over the flywheel's ring gear teeth. The ECU continuously
monitors this signal and
if
there is any discrepancy in this
signal the ECU adjusts the DC voltage to the ACTUATOR
positioning its plunger to let the injection pump fuel rack to
allow more or less fuel delivery to maintain a constant engine
speed depending on the amperage load on the generator.
Maintaining a steady Hertz operation of the AC generator.
The following instructions are for adjusting or replacing the
actuator.
1. Tum OFF the DC breaker on the control box.
2. Unplug the actuator from the engine harness. Back off
the 17116 jam nut that secures the actuator and
unscrew it from the engine block.
3. Apply a small amount of teflon sealant to the actuators
threads and screw it into the engine block
4
to
5
full
tums. Just snug up the jam nut. Reconnect the actuator
to the engille harness. Tum ON the DC breaker on the
control box. NOTE: Tum OFF the
AC
circuit breaker
on the generator.
4. Start the engine. Monitorthe generator output
frequency that it is operating at the selected frequency.
5. With the engine running, depress the STOP switch to
test for proper engine shut down. If the engine does
not shut down and only goes to a slow idle speed,
loosen the jam nut and thread the actuator in slowly
until a full shut down takes place. Then thread the.
actuator in 112 tum and secure it in place with a jam
nut. Un-twist the actuator wires as needed. This
adjustment should now allow the engine to start and
stop under normal operating conditions.
A final adjustment may be necessary after the genset has
operated approximately
20
mluutes and has raeched its
normal operating temperature. If the engine shuts down
properly under normal operating conditions, but fails to shut
down fully under more extreme conditions such as running at
high amperage loads for a long period of time and/or under
extreme ambient temperatures. The actuator may need to be
turned in an additional 1/2 tum.
MAGNETIC PICK-UP [MPUlINSTALLATION
The MPU is installed in the threaded opening on the side
of the flywheel bellhousing. This positions the MPU over
the teeth of the flywheel ring gear.
Viewing through this opening, manually rotate the engine
crankshaft so as to pOSition the flat of one of the ring
gear's teeth directly under the opening. Thread the MPU
into the opening until it gently contacts the flat of this .
tooth (Thread is
3/8"
x
24).
Back the MPU out of the
opening one turn and then lock it in this position with
the jam nut. This will position the end of the MPU
approximately 0.030 inches away from the flats of the
ring gear teeth. .
To ens.ure the MPU is positioned correctly, slowly rotate
the crankshaft by 360· by hand to assure there is no
physical contact between the MPU and
the
ring gear teeth.
If contact is felt between the MPU and the flywheel teeih,
the MPU may be damaged. Remove the MPU and inspect
it. Replace if necessary and repeat the ahove .
installation procedure.
NOTE: When replacing the Magnetic Pick-Up (MPU) it
MUST be replaced without cutting and splicing into the
existing wiring cable. Doing so will cause a erratic
AC
signal to the controller.
RESISTANCE
(at
rest)
950 -1000 ohm
"~
~0.D3Di
WIRES
BOARO
-
-
~ BACKPLATE
~.
SPEED SENSOR TEST VALUES
~
VOLTAGE (while cranking)
1.5· 2.5 VAC
GOVERNOR CIRCUIT VOLTAGES
Below are the voltages normally found in the governor
circuit when the system is functioning normally. These
voltages are an approximate and should be help in
troubleshooting a system that is not functioning correctly.
DC VQJtage IntQ Controller
Bat
+
to Bat - (ba.ttery charging voltage 13.5 - 14.5 VDC)
(Terminal block #1 and
#2) .
DC Voltage to Actuator
ACT to ACT (5.5 - 6.5 VDC)
(Terminal block #5 and #6)
AC Voltage from MPU into Controller
MPU to MPU
(2.S
-7.0 VAC)
(Terminal block #3 and
#4)
This voluige spread is the result of the dislarlce the MPU is
positioned from the flat of the flywheel ring gear tooth.
The closer to the tooth, the higher the AC signal. The
further away, the lower the AC signal.
-..y"
WESTERBEKE
Engines & Gimeralors
91