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
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
driven
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 con-
nected
to
an
air compressor,
for
example, will require more
current
than
a motor
to
which
no
load is connected.
fu
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)
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.
T11e
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 generators data plate. The output voltage
should be checked periodically
to
ensure proper operation of
the generating plant and the appliances it supplies. To
monitor voltage and load, check it with a portable meter
and
amp probe.
40
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 excessive heating and
reduced life
of
windings.
In addition to periodic cleaning, the generator should
be
inspected
for
tightness
of
all connections, evidence of
overheated terminals andloose or damaged
wires.
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