Portable Electric Generators
Portable Electric Generator TIPS
- Allow you to have heat and cooling in power outages
- Small ones, 2,000 watts, are for minimal power requirements
- 5,500 watts is more realistic for output
- WATCH video below of automatic stand-by generator
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DEAR TIM: Last year, we lost electric power to our home three times. One of the outages cost us approximately $400 in spoiled food.
Will a portable generator solve this problem? How do you size a generator?
Can they be safely connected to the electric panel, or do you have to use extension cords to power separate items?
Will these generators supply sufficient power to run sensitive electronic equipment such as my computer? Doug Turner, Oregon
DEAR DOUG: Two years ago, the exact same thing happened to me.
My Own Outages
A few years back, a summer storm left my family and I without power for 36 hours. Then a freak fall snow storm knocked out my power for three days.
A portable electric generator would have allowed me to run my refrigerator and freezer just enough to save my food.
Plenty Of Natural Gas - But NO HEAT
I could have also powered my furnace for 10 minutes an hour to keep the pipes, my wife and kids from freezing. October is normally a balmy month but this storm brought in a bubble of cold air that made it feel like December.
I had an unlimited supply of natural gas coming into my home, but my furnace was ice-cold because there was no electricity to power the thermostats and giant fan that blew hot air to all the rooms.
Sleeping in the family room in front of the fire made us feel like we were in a log cabin.
All because I didn't own a simple portable generator that would have allowed us to not go back in time 100 years!
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Great Machines & Reliability
Portable electric generators come in all sizes and levels of quality. They can provide you with emergency power to run virtually any electric appliance in your home.
They can also provide electric power for picnics, camping and construction needs.
Portable Generators For Smaller Loads
However, if you plan to power a whole house air conditioner or heat pump, you are dreaming. These large electrical devices will overwhelm an average or large size portable generator.
Sized In Watts
Portable electrical generators are sized by the amount of watts they will produce when operating. A 2,500 watt generator will supply enough electricity to power twenty-five 100 watt light bulbs for 30 minutes.
After that, you should reduce the load by 10 percent to avoid overheating the generator.
The total capacity of a generator cannot always be delivered to a single appliance. The power you can deliver to any one appliance is determined by the size of the outlets on the side of the generator.
Add Up Watts To Size One
Sizing a generator for your household emergency needs can be a bit complicated. You need to calculate the total amount of watts (electrical load) you might have connected to the generator at any one time.
Appliances and motors have labels that tell you how many watts the appliance requires while operating. You'll discover quickly that if you want to power several things at once, plus have a few lights burning, you'll need at least 4,500 watts, maybe even 5,500 watts.
Typically you'll discover even with a larger generator you'll have to switch out what things get power.
In other words, you may let the furnace run for an hour, then switch that power cord to the refrigerator. Not all things can have constant power unless you get a massive generator.
Giant Generators - In Case You Must Have One
Watch this video to see my automatic stand-by generator at my own home. It comes on automatically if the main power is out for ten seconds.
This generator can produce 17,000 watts. That may seem like a vast amount of electricity, but it's not enough to power a 240-volt large oven.
Typical Watts For Appliances
- cell phone battery charger - 25 watts
- furnace fan blower - 700 watts
- electric crock pot - 240 watts
- microwave - 700 to 1,200 watts
- video game device - 40 watts
- refrigerator - 550 watts
- water well pump - 575 watts
- hand hair dryer - 1,200 watts
- window air conditioner - 1,500 watts
Start Up Draw
In addition, certain appliances require significantly more power at start-up than while actually running. It takes a big initial surge of power to get the core of the electric motor spinning.
Refrigerators, furnace blower motors, freezers, washing machines, etc. are examples of these appliances.
If you've ever seen your lights temporarily dim while your refrigerator starts up you know what I am talking about.
This is called reactive load and it can be as high as double the running load of an appliance. You need to keep this in mind when sizing a generator.
Well pumps, larger AC units, etc. can have crippling reactive loads and stall out a generator that's too small.
Transfer Switch Is Complicated
Connecting a portable generator to your main electric service panel where the circuit breakers are located is accomplished using a transfer switch. These switches completely take your house off line while the generator is operating.
If you don't use a transfer switch and simply feed power to the electric panel, you could kill a utility company linesman who is attempting to restore power to your neighborhood. These switches also protect the generator when power is restored by the utility company. Make sure a qualified electrician installs your transfer switch. It must be inspected by your local electrical inspectors and/or the utility company.
Generators & Extension Cords
Almost all portable generators come with electrical outlets. You plug in an extension cord into these outlets.
Extension cords are inherently dangerous because all too often they're under sized. This means if you try to put lots of electricity through them they can overheat and cause a fire.
If you choose to use them, be sure they are sized adequately to handle the flow of electricity. An undersized cord can overheat, short out and cause a fire.
CLICK HERE to read my past column about Sizing Extension Cords.
Modern Generators SAFE For Electronics
To power sensitive electronic equipment, you need to purchase the highest quality portable generator you can afford. The quality of electricity produced by different generators can vary.
The gasoline engine and the generator must provide consistent, smooth power. Inexpensive motor or generator components can adversely affect electrical power production.
Consider purchasing an engine that has an automatic shut off that can detect low engine oil levels. This simple feature will protect your engine from failure. Remember, higher quality usually means higher initial cost. The most economical generator may not be the best long term investment.
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