WARNING: Electrocution, severe personal injury or death can occur: Do not connect any generator to any building's electrical system unless an isolation switch has been installed by a licensed electrician. Refer to the Generator Owner's Manual.

CAUTION: Property damage can occur: Do not connect any generator to any building's electrical system unless an isolation switch has been installed by a licensed electrician. Refer to the Generator Owner's Manual.

CHOOSING THE RIGHT GENERATOR

Follow these steps when determining your energy needs:

1. Identify the wattage requirements for the tools and appliances that you want to power. The power requirement for the tool or appliance can be found on its identification plate or in the Owner's Manual. If the power requirement is given in amps, multiply the amps times volts to derive the required watts.

Amps x Volts = Watts

2. Add up the required watts of all the tools and appliances you expect to operate simultaneously.

3. The total watts derived in step 2 is the size Yamaha generator you need. These three simple steps will "size" a generator.


GENERATOR WORKSHEET
RUNNING
WATTAGE REQUIREMENTS
ADDITIONAL STARTING WATTAGE REQUIREMENTS
TOTALS
HEATING/COOLING:
Furnace Fan, gas or fuel oil furnace
1/8 horsepower
300
500
1/6 horsepower
500
750
1/4 horsepower
600
1000
2/5 horsepower
700
1400
3/5 horsepower
875
2350
Central Air Conditioner
10,000 BTU
1500
2200
20,000 BTU
2500
3300
24,000 BTU
3800
4950
32,000 BTU
5000
6500
40,000 BTU
6000
6700
HEATING/COOLING:
SUB-TOTAL:
KITCHEN
Refrigerator, Average 600 2200
Dish Washer - Cool Dry 700 1400
Dish Washer - Hot Dry 1450 1400
Clothes Dryer - Gas 700 1800
Clothes Dryer - Electric 5750 1800
Microwave Oven, 750W 750 800
Washing Machine 750 2300
Coffee Maker 850 0
Toaster 2-slice 1100 0
Toaster 4-slice 1650 0
Electric Skillet 1500 0
Electric Range 6-in. element 1500 0
Electric Range 8-in. element 2100 0
Freezer 2500 2200
KITCHEN SUB-TOTAL:
BATHROOM
Hair Dryer 800 - 1700 0
Iron 1200 0
BATHROOM SUB-TOTAL:
APPLIANCES
Lights- Wattage Actual:
VCR 50 0
Heating Pad 65 0
Radio 100 0
Television - Black & White 100 0
Television - Color 300 0
Dehumidifier 400 0
Electric Blanket 400 0
Garage Door Opener - 1/4HP 550 1100
Garage Door Opener - 1/3HP 725 1400
Well Pump - 1/3 hp 750 1400
Well Pump - 1/2 hp 1000 2100
Sump Pump - 1/3 hp 500-1200 1700
Sump Pump - 1/2 hp 1050 2150
Vacuum Cleaner - Standard 800 0
Vacuum Cleaner - Deluxe 1100 0
APPLIANCES SUB-TOTAL:
COMMERCIAL PRODUCTS:
1/4" Drill 300 300
Jigsaw 300 300
Electric Weed Trimmer 500 500
Router 1000 1000
Belt Sander 1000 1000
Disc Sander 1200 1200
Chain Saw 1200 1200
Worm Drive Saw 1560 3100
12" Concrete Cutter 1800 3600
7 1/4" Circular Saw 1500 3000
Disc Grinder 2000 4000
Air Compressor, Average 2000 4000
COMMERCIAL PRODUCTS: SUB-TOTAL:
GRAND TOTAL

ADDITIONAL GUIDELINES

CONVERTING AMPS OR HORSEPOWER INTO WATTS

Watts = Amps x Volts

Running Watts* = Horsepower x 932** (for motors)

Remember, this worksheet lists average power requirements — a particular manufacturer's device may use more or less than the listed wattage.

  • Add a 10% correction factor to your totals to help overcome this uncertainty.

If your customer plans to operate devices that use electric motors, list both the starting and running requirements of each.

  • Starting requirements of some devices maybe significantly higher than their running requirements . This higher demand must be considered when estimating your power needs. Some small, universal motors — which do not draw a heavy starting load (drills, small saws, blenders, etc.) — require very little extra current for starting.

When listing items that use motors, take them in the order of highest-to-lowest starting requirements, as shown in the example below. Motor A, for instance, has a starting requirement of 2,600 watts, so it's listed first, followed by Motor B at 1,300 watts, and Motor C at 1,000 watts.


MOTOR/
DEVICE
STARTING
WATTS
RUNNING
WATTS
Motor A 2,600 850
Motor B 1,300 600
Motor C 1,000 750

Once you have compiled an accurate list of what you will be operating, you can calculate the maximum power requirements. There are three different calculations you can make, depending upon the kinds of tools and appliances on the list, and their intended use:

  • No electric motors.
  • One motor running at a time.
  • More than one motor running at a time.

NO ELECTRIC MOTORS
If your list does not include any devices that use electric motors, simply add the power (running) requirements of all the items on your list to obtain the maximum power needed.

  • For example, if you intend to use only an electric skillet, a 100-watt light and a heating pad (as shown below), the maximum power requirement would be 1,655 watts. In this case, a generator like the EF2800i, that can produce 2,500 watts rated output, is recommended.

DEVICE WATTS
Electric Skillet 1,500
Light 100
Heating Pad 65
Total: 1,665

NOTE: The EF1600's rated output is 1,400 watts, so its output would be too low to handle this load on a continuous basis.

*Running Watts is the amount of power a motor consumes once it has started to run at normal speed.
**932 is the factor used to convert motor horsepower ratings to needed electrical energy. It takes into account normal losses in utilizing that power.