The growing unquenchable thirst for more power in the developed countries and perhaps more in the developing ones has led to constant innovation, a thirst that has never been quenched since the early industrial revolution to the present 21st century. Various contraptions have been designed to satiate this thirst. An engine generator is one of them.

An electric generator and an internet combustion engine assembled together so as to form a single piece of equipment is called as an Engine- Generator or even more colloquially, it is also called as generator set. They have evolved as a complimentary choice or an alternative for the electric generator and utilize the engine for the mechanical rotary force that needs to be developed for producing electricity.

In general, these generator sets also included a fuel reservoir for the engine, an engine speed regulator and also a voltage regulator. Some units also come equipped with a batter and a self-starter notwithstanding a transfer switch which can be used to load or on load the utility source on or off the generator set combination of an electric generator with an internal combustion engine, mounted

Most of the small and portable generators used in the US today are single- phased and there are very few such generators available. However there are quite a few large ones and most of them operate on three-phased models. While selecting a generator for a particular purpose, the generator voltage, frequency and wattage are carefully chosen to suit the load that is about to be connected to the generator.

Engine- generators also come in a plethora of power ratings, ranging from small portable ones which generate a few hundred watts, moving upwards to the hard-carted, slightly larger ones which can produce up to a few thousands and then onto the stationary ones which can purge millions of watts. The smaller ones usually use gasoline as a fuel, while the larger ones can use variety of fuels like gasoline, diesel, natural gas or propane.

While choosing generators for residential or commercial usage, one needs to carefully assess his or her requirements. For sensitive output demanding installations like computers and other such electronic equipment, invertors, which produce clean-sinusoidal wave electrical currents, might be apt. Places where utility power stations are not present might need the portable devices and where permanent installations are required, for example. Hospitals, factories and communication service centers, the large ones are apt.