Operator`s manual
BT GENERATOR
This generator is a brushless self-excited generator, which requires only the driving force
of
the engine to
produce AC output. The copper and laminated iron in the exciter stator are responsible for the self-
exciting feature
of
this generator. The magnetic field produced causes an AC voltage to be induced into
the related exciter rotor windings during rotation. Diodes located in the exciter rotor rectify this voltage
to DC and supply it to the windings of the rotating field. This creates
an
electromagnetic field which
rotates through the windings
of
the main stator, inducing an AC voltage which is supplied to a load. A
transformer is connected
in
parallel
to
the AC output of the main stator. An AC voltage is produced in
the auxiliary windings of the transformer and main stator and is, in turn, supplied to a full-wave bridge
rectifier. The rectifier produces a DC voltage
to
further excite the excitor stator windings, enabling the
generator to produce a rated AC output.
No-Load Voltage Adjustment
Voltage adjustment is made with the compound transformer goveruing generator regulation.
1.
Operate the generator and apply a moderate load momentarily; then remove the load. Note the voltage
output from the generator's
l20-Volt leg(s) (110 Volts at
50
Hertz). The no-load voltage should be
between
121
-
123
Volts at 61.5 - 62 Hertz
(Ill
-
113
Volts at 51.5 -
52
Hertz).
NOTE: The no-load voltage should be adjusted to the voltage produced by the generator
when: the generator
is
started, a momentary load
is
applied to excite the transformer, and
then removed. The voltage produced
by
the generator after this momentary load is removed
is the no-load voltage.
2.
To raise or lower the voltage, non-<:onductive shims
of
varying thickness are inserted or removed from
under the laminated steel bar that is situated on top
of
the compound transformer. The material used for
shimming should not soften at temperatures in the
176
0
F (80
0
C) range. A small reduction in no-load
voltage
(1
to 3 volts) sometimes can be accomplished by gently tapping the top
of
the laminated steel bar
to reduce the air gap between the existing shims and the transformer core.
II
CAUTION n
Under no circumstances attempt
to
increase the no-load voltage by increasing the gap between
the laminated steel bar and the transformer core without the use
of
shims. Magnetic forces
created within the transformer during the generator's operation
may
close the air gap and
reduce the no-load voltage output.
3.
To remove the laminated steel bar, remove the
two
upper securing bolts from the compound
transformer and lift the bar from the transformer. The addition of shim thickness will raise the no-load
voltage and, conversely, the removal
of
shim thickness will lower the no-load
Voltage.
Varying shim thickness by .001 inch (0.025 mm) will change the no-load voltage by 4 to 6 volts.
51
WESTERBEKE
GENERATORS