GENERATOR
INFORMATION
USE
OF
ELECTRIC
MOTORS
The power required
to
start
an
electric motor
is
considerably
more
than
is
required
to
keep
it running
~r
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
com-
monly 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
connected
to
medium
starting
loads
will
be
approximately
as
follows:
MOTOR
SIZE
AMPS
FOR
AMPS
FOR.
(HP)
RUNNIN~)
(AMPERES
(~TARTIN~)
AMPERES
1/6
3.2
6.4
to
22.4*
114
4.6
9.2
to
32.2*
113
5.2
10.4
to
72.8*
1/2
7.2
14.4
to
29.2*
314
10.2
20.4
to
40.8*
1
13
26to
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
~er
sizes.
Because the
fieavy
surge
of current needed
for
starting
motors
is
required.f6r.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, turn
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
ampere
meter
is
not installed
to
monitor voltage
and load, check it
with
a portable meter and
amp
probe.
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 tenninal 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. A reconfiguration
of the AC output connections at
the
generator is also
neces-
sary.
Generator
Maintenance
• Maintaining reasonable cleanliness is important.
Connections of terminal boards and rectifiers may
become
corroded,
and
insulation surfaces may start
con-
ducting
if
salts,
dust, engine exhaust, carbon, etc.
are
allowed to build
up.
Clogged ventilation openings
may
cause excessive heating
and
reduced life of windings.
• For unusually severe conditions, thin rust-inhibiting
petro-
leum-base coatings, should be sprayed or brushed
over
all
surfaces
to
reduce rusting
and
corrosion. Typical
materials
suggested
are
Daubert Chemical Co. "Non-Rust
AC-
410" and Ashland ''Tectyle 506"
or
equivalent.
• In addition
to
periodic cleaning, the generator should
be
inspected for
(a)
tightness of
all
connections, (b)
evidence
of overheated terminals
and
(c)
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 annature 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
n:rust
be
made quickly or major components
will
rub
an~
cause major damage to generator.
The
generator's
data
plate
gives
the
voltage,current,
and
frequency
rating
of
the
generator.
An
AC
wiring
decal
is
on
the
inside
of
the
louvered
cover
at
the
~
generatpr
end
that
includes
the
AC
voltage
connections.
These
voltage
diagrams
ate
also
shown
on
these
pages.
Enpintis~.Gene,._o.rs
36
To Next Page
Loading...
