Service manual
GENERATOR
INFORMATION
USE
OF
ELECTRIC
MOTORS
The power required to start an electric motor is considerably
more than is required to keep it running after it is started.
Some motors require much more current to start them than
others. Split-phase (AC) motors require more current to start,
under similar circumstances, than other types. They are
commonly used on easy-starting loads, such as washing
machines, or where loads are applied after the motor is
started, such as small power tools. Because they require 5 to
7 times as much current to start as to run, their
use should be
avoided, whenever possible, if the electric motor is to
be
dri-
ven by a small generator. Capacitor and repulsion-induction
motors require from 2 to 4 times as much current to start as
to run. The current required to start any motor varies with the
load connected to it. An electric motor connected to an air
compressor, for example, will require more current than a
motor to which no load is connected.
In general, the current required to start 115-Volt motors con-
nected to medium starting loads will be approximately as
follows:
MOTOR
SIZE
AMPS
FOR
AMPS
FOR
(HP)
RUNNING
STARTING
(AMPERES)
(AMPERES)
1/6
3.2
6.4
to
22.4-
1/4
4.6
9.2
to
32.2-
1/3
5.2
10.4
to
72.8-
1/2
7.2
14.4
to
29.2-
3/4
10.2
20.4
to
40.8-
1
13
26
to
52
*NOTE:
In
the
above table
the
maximum Amps for Starting
is
more
for some small motors than for larger
ones.
The
reason
for
this
is
that
the
hardest starting types (split-phase)
are
not
made
in
larger
sizes.
Because the heavy surge
of
current needed for starting
motors is required for only an instant, the generator will not
be damaged
if
it can bring the motor up to speed in a few
seconds.
If
difficulty is experienced in starting motors, tum
off all other electrical loads and,
if
possible, reduce the load
on the electric motor.
Required
Operating
Speed
Run the generator first with no load applied, then at half the
generator's capacity, and finally loaded to its full capacity as
indicted on the generator's data plate. The output voltage
should be checked periodically to ensure proper operation
of
the generating plant and the appliances it supplies.
If
an AC
voltmeter
or
ampmeter is not installed to monitor voltage and
load, check it with a portable meter and ampprobe.
NOTE:
When
the
vessel
in
which
the
generator
is
installed
contains AC equipment
of
120 volts
only,
it
is
recommended
that
the
generator's AC terminal block
be
configured
to
pro-
vide
one 120 volt AC hot
leg
for
the
vessel's distribution
panel.
This
will
ensure
good motor starting
response
from
the
generator.
Generator
Frequency
Adjustment
Frequency is a direct result
of
engine/generator speed, as
indicated by the following:
• When the generator is run at 1800 rpm, the AC voltage
output frequency is
60 Hertz.
• When the generator is run at 1500 rpm, the AC voltage
output frequency is
50 Hertz.
Therefore, to change the generator's frequency, the genera-
tor's drive engine's speed must be changed. Along with a
reconfiguring
of
the AC output connections at the generator,
a regulator board voltage output adjustment must also be
made.
See ELECTRONIC GOVERNOR in this manual.
Generator
Maintenance
• Maintaining reasonable cleanliness is important.
Connections
of
terminal boards and rectifiers may become
corroded, and insulation surfaces may start conducting
if
salts, dust, engine exhaust, carbon, etc. are allowed to
build up. Clogged ventilation openings may cause exces-
sive heating and reduced life
of
windings.
• For unusually severe conditions, thin rust-inhibiting
petroleum-base coatings, should
be
sprayed or brushed
over all surfaces to reduce rusting and corrosion.
• In addition to periodic cleaning, the generator should be
inspected for tightness
of
all connections, evidence
of
overheated terminals and loose or damaged wires.
• The drive discs on single bearing generators should be
checked periodically
if
possible for tightness
of
screws
and for any evidence
of
incipient cracking failure. Discs
should not be allowed to become rusty because rust may
accelerate cracking. The bolts which fasten the drive disc
to the generator shaft must be hardened steel
SAE grade
8,
identified by 6 radial marks, one at each
of
the 6 cor-
ners
of
the head.
• The rear armature bearing is lubricated and sealed; no
maintenance is required. However,
if
the bearing becomes
noisy or rough-sounding, have it replaced.
• Examine bearing at periodic intervals. No side movement
of
shaft should be detected when force is applied. if side
motion is detectable, bearings are wearing or wear on
shaft
of
bearing socket outside bearing has occurred.
Repair must be made quickly or major components will
rub and cause major damage to generator.
Carbon
Monoxide
Detector
------------,
WES1ERBEKE recommends mounting a carbon
monoxide detector in the vessels living quarters.
Carbon
monoxide, even
in
small
amounts
is deadly.
The presence
of
carbon monoxide indicates
an
exhaust
leak from the engine or generator, from the exhaust
elbow/exhaust hose, or that fumes from a nearby vessel
are entering your boat.
If
carbon monoxide is present ventilate the area with clean
air and correct the problem immediately!
Engines & Generators
59