Generators

A lower-cost alternative to home standby systems is to use a portable generator of the appropriate wattage for your needs (at least 4000 Watts for starters) and run extension cords into the house to power chosen appliances. A safer system is to install a power transfer switch, connected to the house's main electrical panel. Just fire up the generator, run a single extension cord into the transfer switch and power the circuits you need through the main circuit breaker. This eliminates the risk of electrical "back feed" injuring utility workers repairing downed power lines.

A small portable gasoline-powered electric generator can provide power for TVs, small kitchen appliances, hair dryers, power tools, lights and other comforts of civilization when you are out roughing it in the woods.

er portable generators can be put to work on construction sites that have no electrical service, providing clean, reliable power to operate saws, drills, air compressors, heaters, paint sprayers and other AC-powered tools. Most are gasoline-powered, a few run on diesel, and some models have multi-fuel capabilities, running on gasoline, propane or natural gas. These are generally full-featured machines with engine idle control, GFCI receptacles and 120 Volt full power switch.

Residential Standby Systems
An emergency home standby generator system can automatically restore power to your house in about 20 seconds. When the power goes out, the generator automatically starts and continues to run until power is restored. You can choose a generator that delivers enough power for the entire house (including air conditioning) or go with a smaller unit and power a few selected circuits, like the refrigerator, sump pump, furnace fan and several lights for basic survival.

These all-weather generators are installed outside the home and are wired through an automatic transfer switch (sold separately) to the main electrical panel. The use of an automatic transfer switch is required when generators are connected to home wiring.

Home standby systems can be fueled by natural gas, LP gas or diesel fuel. Many models can be connected to the home's natural gas line, eliminating the need to fill fuel tanks. Standby system capacities range from 6,000 Watts up to 40,000 Watts and more, and start automatically-even if you are not home.

Commercial Standby Systems
If you have a business that simply can't be without power or you have no existing source of electrical power for your home or business, you will need an industrial generator. These are typically stationary, heavy-duty units that generate single (120 Volt) or three-phase (120, 240 or 480 Volt) power. These massive systems are powered by water-cooled diesel engines, with some models generating up to 200 KW (200,000 Watts) of power. With the use of an automatic transfer switch, these generators can serve as backup power for large commercial or industrial operations, such as nursing homes, refrigeration operations, farms, large buildings and other businesses that can't go without power due to an outage.

RV Generators
Quiet, powerful gasoline, diesel or LP-powered generators can be installed in your RV, 5th wheel trailer, truck camper, tent trailer or travel trailer to provide electrical power.

PTO and Belt-Drive Generators
Create power on demand by attaching a generator to the PTO on your tractor or construction equipment. Belt-driven generator heads work with your existing gas engines. They are less expensive because the engine is not included.

How Many Watts Will Your Generator Need to Produce?

You first need to determine the electrical load that your generator will need to supply. There are resistive loads (like lights and heaters) that don't require extra power to start. Reactive loads (like electric motors) have starting requirements that can be double or triple the normal running wattage requirement. You will want to use the starting requirement in your calculations.

Generator power is measured in Watts: Watts = Volts x Amps
Most home appliances and power tools are 120 Volts; larger appliances like electric stoves and clothes dryers may be 240 Volts. For reactive load devices that have higher starting requirements, multiply the Amps x Volts x 3 (starting requirement) = Watts
EXAMPLE: 1 HP Motor requires 13.3 Amps at 120 Volts to run, plus 3x load factor for starting 13.3 Amps x 120 Volts x 3 (starting requirement) = 4,788 Watts

You can use our Wattage Chart below to estimate the wattages of the tools, appliances and motors you will be operating at the same time. Add up the wattage of the tools, appliances and motors you will be running at the same time. Then, select the generator with the continuous wattage rating that meets or exceeds your total load.

Tools Power Required

Air Compressors, 1/2 HP 1500 - 3000W

Circular Saw, 7 1/4" 1000 - 2500W

Electric Chain Saw, 14" 800 - 1500W

Electric Drill, 1/4" and 3/8" 300 - 600W

Electric Drill, 1/2" 350 - 1200W

Grinders, 6" 1000 - 2600W

Jig Saw 200 - 800W

Paint Sprayer 800 - 1300W

Portable Oil Heater 900 - 1000W

Router 900 - 1000W

Sander, 4" Belt 700 - 1500W

Soldering Iron 100 - 300W

10 Amp Battery Charger 300 - 400W

Electric Motors* Power Required

1/6 HP, 460 Watt 340 - 850W

1/4 HP, 725 Watt 450 - 1050W

1/3 HP, 800 Watt 560 - 1300W

1/2 HP, 970 Watt 760 - 1800W

3/4 HP, 1340 Watt 1080 - 2600W

1 HP, 1700 Watt 1250 - 3000W

1 1/2 HP, 2300 Watt 1600 - 4200W

Household Uses Power Required

Air Conditioner 10,000 BTU 2000 - 3000W

Coffee Pot 1000 - 1500W

Electric Heater 1000 - 2000W

Electric Stove (one element) 750 - 1800W

Gas Furnace 300 - 1500W

Hair Dryer 800 - 1500W

Iron 1000 - 1500W

Microwave 500 - 1500W

Oil Furnace 400 - 2000W

Radio 30 - 100W

Refrigerator/Freezer 600 - 2500W

Sump Pump 800 - 3000W

Television 100 - 350W

Toaster 1100 - 1700W

Water Pump 1000 - 3000W

*Electric motors require at least three times more wattage when first starting than when running.

Finally, add together the wattage requirements for all the electrical devices that you want to run or start at the same time. This is the minimum continuous wattage you will need from a generator.

Typical Home Standby Power Needs:

Minimum Recommendations for Typical Home Standby Power (1 kw = 1,000 watts)

Customer Type One Item at a time Two Items at a time All Items at once

Customer #1

Lights
Color Television
Furnace Fan
Freezer
Refrigerator
Sump Pump 2.4kw
2.4kw
2.4kw
2.4kw
2.4kw
4.5kw 4.5kw 6.6kw

Customer #2

Includes Customer #1 and central air 4.5kw 6.6kw 10.5kw

Customer #3

Includes Customer #1 and a well pump 4.5kw 6.6kw 10.5kw

Customer #4

All of the above 4.5kw 6.6kw 13.5kw

When in doubt, remember that bigger is better!

Engines and Alternators: What to Look For

Brand Name
Choose a portable generator equipped with a brand-name engine that you know and trust, such as Honda, Briggs & Stratton and Tecumseh.

OHV (Overhead Valve) Engine
OHV engines start easier, run quieter, last longer and produce less emissions than side-valve (pushrod) engines.

Cast Iron Sleeve
The cast iron sleeve is a liner in the cylinder of some engines which reduces wear and makes the engine last longer. The added cost of an engine with a cast iron sleeve is small and well worth it, if you expect to operate your generator often or for long periods of time.

Low Oil Shutdown
This feature shuts the engine down if the oil level drops below a safe operating level, especially recommended for generators with large fuel tanks.

Electric Start
Enables easy starting of generator without having to pull a starter rope.

Full Power Switch
Allows you to switch off the 240 Volt output to get more 120 Volt power from the generator, useful for starting 120 Volt electric motors on air compressors and water pumps.

Idle Control
Automatically throttles down engine when no power is being drawn from alternator, reducing engine wear and noise.

Hour Meter
Keeps a record of how long engine has run. Can help with oil change scheduling.

Portability Kit
Includes wheels and handles for moving the generator around. Can be a real back saver when using units that weigh over 100 lbs.

Large Fuel Tank
Generators with a fuel tank of 5 gallons or larger can typically run 7 to 10 hours on a single fill, useful for providing backup power during power failures.

All-Metal Alternator
Get an all-metal alternator because plastic housings can warp over time and cause the moving parts of the alternator to come out of alignment and break or wear excessively.

Total Harmonic Distortion (THD)
Total Harmonic Distortion is a means to measure the quality of electricity. 6% THD is considered the upper limit for "clean" electricity. Above 6% THD the electricity may reduce the life of electrical circuits, cause microprocessors to malfunction and cause furnace controllers to operate incorrectly. All NorthStar generators have THD less than 6%. Some generators produce THD greater than 15%.

Brushless Alternator Des