Governor System Components And Operation - Westerbeke 5.0KW BCG-60Hz Service Manual

GOVERNOR SYSTEM COMPONENTS
and OPERATION
DESCRIPTION
The Electronic Governor consists of three components, the
CONTROLLER,
a pc board installed in the control panel. A
MAGNETIC PICK·UP
(MPU) installed in the bellhousing over
the engine flywheel and the linear
ACTUATOR
mounted on the
engine and attached by linkage to the injection pump
throttle control.
SYSTEM OPERATION
On start up system DC voltage is supplied to the controller to
use for actuator operation. When the starter is energized and
the engine cranks, the magnetic pick-up (MPU) that is
positioned over the engines flywheel ring gear sends a low
AC signal to the controller (1.5 - 2.5 AC volts).
The controller interprets this as engine cranking speed and
sends a DC voltage to the actuator
to
operate the carburetor's
throttle ann. The position of the throttle by the actuator has
been previously determined by the speed adjustment on the
speed controller. The engine carries up to a set speed
determined by the AC voltage sent by the MPU.
The speed controller maintains this signal no load to full load
by varying the DC voltage to the actuator providing more or
less tlu'ottle depending on the generator load.
Gain Adjustment
The gain can be adjusted using a small screwdriver.
Adjustment should be between 30% and 40% as is required
to dampen speed oscillation under load.
An
adjustment of
more than 40% can cause the unit to race (speed up) when
the load is removed or go into a hunting mode.
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GAIN ADJUSTMENT
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Speed Controller
The speed controller has a green LED indicating power to
the controller, a plus and minus speed adjustment (buttons)
and a gain adjustment. The green LED blinks when the
power is tumed on and after it receives a signal from the
magnetic pick-Up, it blinks at a faster rate.
GAIN
ELECTRONIC SPEED
CONTROLLER
MAGNETIC PICK-UP [MPU] INSTALLATION
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 tum 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 ensure the MPU is positioned correctly, slowly rotate
the crankshaft by 360
0
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 teeth,
the MPU may be damaged. Remove the MPU and inspect
it. Replace if necessary and repeat the above
installation procedure.
;=::,.=:=====
D.D30in
NOTE:
If 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.
GOVERNOR CIRCUIT VOLTAGES
Monitoring the voltages found in the electronic governor's
circuit will be helpful in determining where in the circuit
the operating fault lies and with which component.
The circuit voltages listed with the circuit "wiring
schematic" are the approximate voltages found in the
governor circuit with the unit running at idle and at
normal 1800rpm.
The electronic governor's circuit voltages can all be read
and monitored from the connections on the 12 position
terminal strip as illustrated.
Engines
&
Generators
49