Owner’s manual, Determining electrical load for generator – Master Lock MGR2900A User Manual

Page 9

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OWNER’S MANUAL

Running Starting

Equipment

Watts

Watts

1/2" Drill

1000

1250

Toaster

1200

1200

Coffee maker

1200

1200

Skillet

1200

1200

14" Chain saw

1200

1500

Water well pump

(1/2 hp)

1000

3000

Hot plate/range

(per burner)

1500

1500

10" Table saw

2000

6000

Water heater

(storage-type)

5000

5000

Running Starting

Equipment

Watts

Watts

Light bulb (100W)

100

100

Radio

150

150

Fan

200

600

Television

400

400

Furnace fan (1/3 hp)

with blower

600

1800

Vacuum cleaner

600

750

Sump pump (1/3 hp)

700

2100

Refrigerator/freezer

800

2400

6" Circular saw

800

1000

Floodlight

1000

1000

Note: Some motors require 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.

* – Always use starting watts, not running watts, when figuring correct electrical load.

x – Motors of higher horsepower are not generally used.

Chart 1 - Typical Electric Appliance Wattages

DETERMINING

ELECTRICAL LOAD

FOR GENERATOR

You must decide what electrical load your

generator can power. Do this before us-

ing 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

wattage of generator. For rated wattage of

your generator, see Specifications, page 5.

Electric 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.

2. Enter running watts of each item except

motors. The light bulb or appliance

nameplate lists its wattage. Remem-

ber, 1KW = 1000 watts. Note: The

nameplate 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, be-

low, shows starting watts for different

size motors. For example: an electric

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 for motors,

you must use the starting watts figure.

Do not use the running watts figure.

Approximate Starting Watts*

Motor Approximate

Universal

Repulsion

Split

HP

Running

Motors

Induction

Capacitor

Phase

Rating

Watts

(small appliance)

Motors

Motors

Motors

1/8

500

625

1100

1500

2250

1/4

700

875

1550

2100

3150

1/3

800

1000

1750

2400

3600

1/2

1100

1375

2400

3300

4950

3/4

1400

1750

3100

4200

x

1

1700

2125

3750

5100

x

1

1

/

2

2100

2625

4620

6300

x

2

2450

3075

5400

7350

x

3

3600

x

7900

10800

x

Chart 2

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