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6. RANGE OF APPLICATIONS
Generally, the power rating of an electrical appliance indicates the amount of work that can be
done by it. The electric power required for operating an electrical appliance is not always equal
to the output wattage of the appliance. The electrical appliances generally have a label show-
ing their rated voltage, frequency, and power consumption(input wattage). The power con-
sumption of an electrical appliance is the power necessary for using it. When using a generator
for operating an electrical appliance, the power factor and starting wattage must be taken into
consideration.
In order to determine the right size generator, it is necessary to add the total wattage of all
appliances to be connected to the unit.
Refer to the followings to calculate the power consumption of each appliance or equipment by
its type.
(1) Incandescent lamp, heater, etc. with a power factor of 1.0
Total power consumption must be equal to or less than the rated output of generator.
Example : A rated 3000 W generator can turn thirty 100W incandescent lamps on.
(2) Fluorescent lamps, mercury lamps, etc. with a smaller power factor
Select a generator with a rated output equivalent to 1.2 to 2 times of the power consump-
tion of the load.
Example : A 400W mercury lamp requires 600 W to 700 W power source to be turned on.
A rated 3000 W generator can power four or five 400 W mercury lamps.
NOTE 1 : If a power factor correction capacitor is not applied to the mercury lamp or fluorescent
lamp, the more power shall be required to drive those lamps.
A rated 3000W generator can drive one or two 400W mercury lamps without power fac-
tor correction capacitors.
NOTE 2 : Nominal wattage of the fluorescent lamp generally indicates the output wattage of the
lamp.
Therefore, if the fluorescent lamp has no special indication as to the power consumption,
efficiency should be taken into account as explained in item (5) on the following page.
(3) Motor driven tools and light electrical appliances
Generally the starting wattage of motor driven tools and light electrical appliances are 1.2
to 3 times lager than their running wattage.
Example : A rated 250 W electric drill requires a 400 W generator to start it.
(4) Initially loaded motor driven appliances such as water pumps, compressors, etc.
These appliances require large starting wattage which is 3 to 5 times of running wattage.
Example : A rated 900 W compressor requires a 4500 W generator to drive it.
NOTE 1 : Motor-driven appliances require the aforementioned generator output only at the starting.
Once their motors are started, the appliances consume about 1.2 to 2 times their rated
power consumption so that the excess power generated by the generator can be used for
other electrical appliances.
