A portable generator is a gas or diesel-powered device which provides temporary electrical power. The engine turns a small turbine, which in turn creates usable electricity up to a certain level of wattage. Users can plug electrical appliance or tools directly into the generator's sockets, or the generator can be professionally wired into the sub-panel of a home.
Many construction teams use a portable generator to power tools and lights at a remote site. Sports officials may also bring in one to aid in night play or to run an electronic timer/scoreboard. Most commonly, residents and businesses left without power after a weather event will use a portable generator to keep vital appliances operating. These devices usually have enough power to keep a freezer, refrigerator, television and some lights working.
Because a portable generator uses a combustion engine to generate electricity, it must have several regulators on board. The engine must turn at 3600 rpm in order to generate the standard 60hz of alternating current in North American homes. In order to control engine speed, a generator uses a 'governor' which mechanically keeps the engine from spinning too fast. A voltage regulator also keeps the output at 120 volts, which keeps electric motors from burning out.
For safety reasons, these devices must be operated under dry conditions in a ventilated outdoor area. Carbon monoxide fumes can build up from the exhaust of the generator's engine, so indoor use is strongly discouraged regardless of the ventilation system. Touching a working portable generator with wet hands can cause electrocution. A canopy can be placed over the generator to protect it from the elements, but the ground below it should be dry.
A portable generator is designed to be a temporary electrical generator, measured in hours of use instead of days. Size does matter when it comes to the capacity the device. The key measurement is total wattage. All electrical motors need more power to start than to run. Before plugging appliances into the generator, add up the total number of watts all of them will require. This information should be found on a plate near the plug. Compare this number to the wattage rating. The generator needs to produce an equal or higher amount of wattage in order to work safely. This may mean sacrificing the use of an air conditioner in favor of a refrigerator. A bigger generator with a higher wattage rating means more available power for higher wattage tools and appliances.