Determining Electrical Load For Generator - Desa PowerFast PGH7500IE, PowerFast PGH1100IE Owner's Operation And Installation Manual

PORTABLE GASOLINE GENERATORS
DETERMINING
ELECTRICAL LOAD
FOR GENERATOR
You must decide what electrical load your
generator can power. Do this before using
generator. Use the following four-step
method. It will help you select a load that is
not too large. Make sure total wattage of all
electrical loads does not exceed rated watt-
age of generator. For rated wattage of your
generator, see Specifications, page 5. Elec-
tric motors present a special problem when
figuring load. Read Step 3 carefully.
1. Make two lists of items you want pow-
ered by generator. List all motors and
motor powered appliances in one. List all
lights, small appliances, etc. in the other.
For standby service to home or building,
only include items you must power.
Chart 1 - Typical Electric Appliance Wattages
Running Starting
Equipment Watts
Light bulb (100W) 100
Radio 150
Fan 200
Television 400
Furnace fan (1/3 hp)
with blower 600
Vacuum cleaner 600
Sump pump (1/3 hp) 700
Refrigerator/freezer 800
6" Circular saw 800
Floodlight 1000
Chart 2
Motor Approximate
HP Running
Rating Watts
1/8 275
1/4 400
1/3 450
1/2 600
3/4 850
1 1000
1 1/2 1600
2 2000
3 3000
* – Always use starting watts, not running watts, when figuring correct electrical load.
x – Motors of higher horsepower are not generally used.
2. Enter running watts of each item ex-
cept motors. The light bulb or appliance
nameplate lists its wattage. Remember,
1KW = 1000 watts. Note: The name-
plate may not list wattage. It may only
list volts and amps. The formula for
finding wattage is: Volts x Amps =
Watts. For example: An appliance
nameplate states 3 amps at 120 volts. 3
amps x 120 volts = 360 watts.
3. Electric motors present a special prob-
lem. They require up to three-times
their rated wattage to start. Chart 2,
below, shows starting watts for differ-
ent size motors. For example: an elec-
tric motor nameplate states 5 amps at
120 volts. 5 amps x 120 volts = 600
watts running. Multiply this figure by
3. This will show the starting watts
needed. 600 watts x 3 = 1800 watts to
start. When figuring the generator load
Watts Equipment
100 1/2" Drill
150 Toaster
600 Coffee maker
400 Skillet
14" Chain saw
1800 Water well pump
750 (1/2 hp)
2100 Hot plate/range
2400 (per burner)
1000 10" Table saw
1000 Water heater
(storage-type)
Approximate Starting Watts*
Universal Repulsion
Motors Induction
(small appliance) Motors
400
500
600
750 1300
1000 1900
1250 2300
1750 3200
2350 3900
x 5200
Running Starting
Watts Watts
1000 1250
1200 1200
1200 1200
1200 1200
1200 1500
1000 3000
1500 1500
2000 6000
5000 5000
Split
Capacitor Phase
Motors Motors
600 850 1200
850 1050 1700
975 1350 1950
1800 2600
2600
3000
4200
5100
6800
10
for motors, you must use the starting
watts figure. Do not use the running
watts figure. Note: Some motors re-
quire nearly the same wattage to run as
to start. These items include saws,
drills, hair dryers, and food mixers. See
Chart 1 for typical appliance wattage
examples.
4. Add watts and starting watts of all
items. This total must not be larger than
the rated wattage of your generator. It
is a good idea to have up to 25% extra
capacity for future needs or extra
equipment.
x
x
x
x
x
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