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
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
tum,
supplied to a full-wave bridge
rectifier. The rectifier produces a DC voltage to further excite the exciter stator windings, enabling the
generator to produce a rated AC output.
An optional solid-state voltage regulator is available to work in tandem with the transformer regulator to
produce a more stable AC output.
No-Load
Adjustment
Voltage adjustment is made with the compound transformer governing generator regulation.
1.
The seletor switch must be
in
the COMP position.
2.
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) (220 Volts at
50
Hertz). The no-load voltage should be
between 118 - 128 Volts at 61.5 - 62 Hertz (218 - 228 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 alier this
momentary load is removed is the no-load Voltage.
3.
To raise or lower the voltage, non-conductive 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
(I
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
II
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.
4. 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
the 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.
WESTERBEKE
GENERATORS
60