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Portable Generators

Portable generators provide electricity by running a gas-powered engine that turns an on-board alternator to generate electrical power. Power outlets on the unit allow you to plug extension cords, electric-powered tools and appliances into it. Unlike standby generator systems, portable generators are not permanently installed, can be easily moved from place-to-place and must be manually started.

What portable generator do I need?

It depends on what you will use it for. Different types of portable generators are better suited for certain tasks. A small generator for tailgating won’t run multiple tools on a job site.

Requirements make a good starting point but there are other factors to consider. Generators designed for RVing, tailgating, and camping are small and lightweight, efficient, and exceptionally quiet. Power the air conditioner and a few lights, charge up electronics, and keep a small refrigerator cold or heat something in the microwave.

On the other hand, contractors need generators that supply enough power for multiple tools all at the same time. They are large and heavy, noisy, and portable means they need two to four guys or perhaps a small crane to lift them off the truck.

In the middle ground are general purpose portable generators that supply 3,000 to 7,000 watts of power. Plenty if you need to run one or two tools at the back of the lot or keep a few crock pots running at a family picnic.

What can I run with a portable generator?

Camping – Fan, coffee maker, refrigerator, bug zapper, campfire lights.

Work –Saws, drills, compressors, pumps, lighting, shop vac.

Home – Refrigerator, freezer, sump pump, television, lights, cell phone.

In fact, you can run just about anything you want provided the portable generator supplies enough power. Some do certain jobs better than others. Small portable generators may only supply 120 volts and one or two receptacles for a few lights and charging a cell phone. Larger generators can supply 240 volts and power an entire house in an emergency, although standby generators do that job much better than portables.

Think about the outlets in your home. Each 15-amp outlet delivers up to 1,800 watts. 20-amp outlets 2,400 watts. If you plug in too much or a load the outlet cannot handle, the breaker trips. The same happens on a generator. A generator rated for 2,000 watts delivers a little more than one 15-amp outlet.

How much power do I need?

Total the power usage in watts of everything the portable generator will run at the same time, then add in the starting watts for the largest motor, and the total is how much power you need.

Motors in general need about three times as many watts to start as to run and that can substantially increase the power requirements of your generator. If the manufacturer designed the motor to start under a heavy load (compressors, pumps) it might need six times as much power to start—an important factor to consider.

Light bulbs, toasters, most electronics, electric heaters, and similar devices don’t require that extra boost of power. Just add their power into the total load.

Portable Generators have two ratings. Surge watts provide an extra boost of power available for a very short time to help start motors. Continuous watts refer to the generator’s actual rated capacity. Manufacturers sometimes name portable generator by the surge watts instead of the continuous watts.

Use Portable Electric Generators Safely

Portable electric generators can offer many benefits when a long-term electrical outage occurs due to a storm. However, if you do not know how to use them properly, they can be dangerous. Contact a qualified vendor. or electrician to help you determine what generator is best suited to your needs. Before using, be sure to read and follow manufacturer's instructions.

Follow these tips to prevent misuse of portable electrical generators:

  • Be sure to follow manufacturers’ directions for installation and operation.

  • To prevent electric shock, make sure your generator is properly grounded. The operation manual should provide correct grounding procedures.

  • Operate electric generators or other fuel-powered machines outside where deadly carbon monoxide fumes cannot enter the home.

  • Use the generator only in a well-ventilated and dry area located away from air intakes to the house. Do not use a generator in an attached garage.

  • Turn the generator on before plugging in appliances to it. Once the generator is running, turn your appliances and lights on one at a time to avoid overloading the unit. Do not overload the generator by operating more appliances and equipment than the generator can handle. Remember, generators are for temporary usage, prioritize your needs. The operating instructions should have an output rating for the generator.

  • Individual appliances should be plugged directly into the receptacle outlet of the generator using appropriately sized extension cords to carry the electric load.

  • Make sure the cords are rated for outdoor use, have a grounded, three-pronged plug, and are in good condition.

  • Do not run extension cords under rugs.

  • Never connect generators directly to your home’s wiring. The reverse flow of electricity can electrocute an unsuspecting utility worker.

  • Never plug a generator into a household outlet.

  • Do not refuel a generator while it is running. Be sure the generator is turned off and cool before fueling it.

  • Generators pose electrical risks especially when operated in wet conditions. Use a generator only when necessary when weather creates wet or moist conditions. Protect the generator by operating it under an open, canopy-like structure on a dry surface where the water cannot form puddles under it. Always ensure that your hands are dry before touching the generator.

  • Only store fuel outside of living areas and away from heat sources like water heater pilot lights.

  • Turn off all equipment powered by the generator before shutting it down.

  • Keep children and pets away from generators at all times. Many generator components are hot enough to burn you during operation.

If you are considering purchasing a generator, please call us with any questions.

Watts (W) and Kilowatts (kW) are units of power. They measure how much work electricity is doing or the capacity to do work. Small portable generators are often rated in watts. Standby generators and larger portable generators are rated in Kilowatts.

1 Kilowatt = 1000 Watts. Watts X 1000 = Kilowatts.

Running Watts or Kilowatts refers to the amount of power the generator can produce continuously. Starting Watts or Kilowatts refers to a surge capacity for a few seconds to start motors, which require much higher power to start from fully stopped.

Kilowatt-Hours or kWh is a measure of energy used. 1 kilowatt used for 1 hour is 1 kWh or 1 kilowatt-hour. The number shown on an electric bill or given as the storage capacity of a battery is energy as kWh or watt-hours Wh.

If you fill a one-gallon bottle of water, you have one gallon. Amperes are a similar measure for how much electricity is flowing at any given moment. Electricity is the movement of electrical charges. One Ampere = 6.2415090744×1018 elementary charges moving past a point in one second. We can say that elementary charges are electrons.

Small quantities do little work. Large quantities can do much more. Motors are a familiar part of everyday life and they do work. Large motors use many amps and do a lot of work like cooling your home when it’s hot. Small motors use only a few amps and do small amounts of work like turn an exhaust fan in your kitchen.

What are Volts?

How fast will the faucet fill that one-gallon bottle mentioned in the previous section? It depends on how much pressure there is behind the water in the faucet. High pressure fills the bottle faster than low pressure because it pushes the water harder and faster.

Voltage is very much like water pressure. It pushes electricity through a wire. The harder it pushes, the more work it can do. However, unlike the faucet, electricity always moves at the same speed in a wire no matter how high the voltage.

As we mentioned above, Watts and Kilowatts measure work done or the potential to do work. Volts X Amps = Watts.

120 Volts X 10 Amperes = 1200 Watts or 1.2 Kilowatts.

12 Volts X 10 Amperes = 120 Watts or 0.12 Kilowatts.

240 Volts X 5 Amperes = 1200 Watts or 1.2 Kilowatts.

In the first two examples we have 10 Amperes, but the volts in the first case is 10 times higher than the second case, and the result is 10 times the work. In the third case, we only have 5 Amps, but the Volts is twice that of the first case, so the work done is still 1200 watts.

In North America, the electric utilities supply 240 volts to homes over two wires, each one at 120 Volts (120/240 Volts.) Larger buildings and businesses may use 120/208, 120/240, or 277/480 Volts.

Internal combustion engines burn fuel to create rapidly expanding hot gases that push pistons down and turn a shaft. Some heat escapes through the exhaust. The engine absorbs the remaining heat. High engine temperatures can cause catastrophic damage.

Small engines like a lawn mower can cool themselves using the air surrounding the engine. The Larger engines found in a standby generator usually use a fan to move cooler air through the generator enclosure, over the engine and other parts to remove heat.

Air Cooling has limitations. As engines grow larger, some parts of the engine may not transfer heat to the air fast enough to cool it. In hot climates with temperatures frequently above 100 degrees, the hot air doesn’t provide enough cooling.

A liquid-cooled engine has built-in channels for coolant. The coolant pump circulates liquid through the engine to a radiator. An electric or belt-driven fan blows air through the radiator to remove heat from the coolant.

Cars and trucks use this method to keep the engine cool. It works well for larger engines with more than two cylinders. The largest engines in the world use the same basic strategy to remove heat as modern cars and larger generators.

Liquid-cooled engines experience fewer problems in desert climates. They efficiently remove heat in temperatures up to 120 degrees Fahrenheit and beyond. Air Cooled Generators may shut down because they can’t cool themselves faster than they create heat.

Transfer Switches supply power directly to a home or business electrical system. A manual switch requires someone to move the switch from utility power to generator power. An Automatic Transfer Switch (ATS) does it without human intervention.

The ATS is an essential part of the Standby Generator System. Without it, the generator can’t supply power to the building without human intervention.

An ATS makes the generator system fully automatic and starts the generator in any weather, even a hurricane, to restore power a few seconds after it goes out.

Throughout most of the world, electric utilities generate 3-phase current. In the section above titled “Voltage—What Are Volts?” we stated that most homes have two lines at 120-Volts each. The two 120-volt lines come a single phase of the local utility’s distribution grid. A standby generator for a home only generates one phase at 120/240-Volts.

Businesses, manufacturing, and industry may use three phases of current from the distribution grid in one of three configurations: 120/208-Volts, 120/240-Volts, or 120/480-Volts 3-phase.

Electrical systems designed to run on 120/240 single phase can’t run on anything else without special equipment. Likewise, 3-phase systems can’t run on single phase without a special converter.

When choosing a generator, it’s important to choose one that supplies the correct voltage and phase.