Master Lock MGY5000 installation manual Determining Electrical Load For Generator, Chart

DETERMINING ELECTRICAL LOAD FOR GENERATOR

18

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 5000 watts. Electric motors present a special problem when figuring load. Read Step 3 carefully.

1.Make two lists of items you want powered 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. 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 name- plate states 3 amps at 120 volts. 3 amps x 120 volts = 360 watts.

3.Electric motors present a special problem. They require up to 3-times their rated wattage to start. Chart 2, below, 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. 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 5000 watts. It is a good idea to have up to 25% extra capacity for future needs or extra equipment.

Chart 1—Typical Electric Appliance Wattages

	Running	Starting		Running	Starting
Equipment	Watts	Watts	Equipment	Watts	Watts
Light bulb (100W)	100	100	1/2" Drill	1000	1250
Radio	150	150	Toaster	1200	1200
Fan	200	600	Coffee maker	1200	1200
Television	400	400	Skillet	1200	1200
Furnace fan (1/3 hp)	600	1800	14" Chain saw	1200	1500
Vacuum cleaner	600	750	Water well pump
Sump pump (1/3 hp)	700	2100	(1/2 hp)	1000	3000
Refrigerator/freezer	800	2400	Hot plate/range
6" Circular saw	800	1000	(per burner)	1500	1500
Floodlight	1000	1000	Water heater	5000	5000

Chart 2

		Approximate Starting Watts*
Motor	Approximate	Universal	Repulsion		Split
HP	Running	Motors	Induction	Capacitor	Phase
Rating	Watts	(small appliance)	Motors	Motors	Motors
1/8	275	400	600	850	1200
1/4	400	500	850	1050	1700
1/3	450	600	975	1350	1950
1/2	600	750	1300	1800	2600
3/4	850	1000	1900	2600	x
1	1000	1250	2300	3000	x
1 1/2	1600	1750	3200	4200	x
2	2000	2350	3900	x	x

*– Always use starting watts, not running watts, when figuring correct electrical load. x – Motors of higher horsepower are not generally used.