Generator Information - Westerbeke 5.0KW BCD Operator's 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 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) RUNNING
STARTIN~)
(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.S·
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 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 impOliant.
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 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 tJ:.l.ust be made quickly or major components will
rub and cause major damage to generator.
Engines
&
Generators
44