Operator`s manual
BT
GENERATOR
This generator is a four-pole, 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 wind-
ings
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
(see the
top
of
page 34).
No-Load
Voltage
Adjustment
Voltage adjustment is made with the compound transformer governing generator regulation.
1.
The selector switch must be in the
CaMP
position.
2.
Operate the generator and
apply
a moderate load momentarily; then remove the load. Note the voltage
output from the generator's
120-Volt leg(s) (110 Volts
at
50 Hertz). The no-load voltage should be be-
tween
121
- 123 Volts
at
61.5 - 62 Hertz
(111
- 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.
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 volt-
age
(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.
See the next page
for
an
illustration
of
the generator's AC distribution box.
33