Terminology and Technology you need understand.
STAND-BY OR PRIME?
Will you require stand-by or prime power supply? Simply stated, prime power is required when you have no other source of power.
A stand-by generator set is a backup to utility power
Why differentiate? The rating of a generator for backup power assumes the generator will be in occasional use for periods of several hours or days. Prime power generators are expected to run 7/24 for 365 days per year. Generators are rated are higher for backup use than for prime power.
USED as an Option
There are good deals to be found within the used market. We come across generators which have been installed for many years as backup with incredibly low hours on the equipment. However, if your application is critical or you require the unit for prime power you must understand that parts, although available, may not be readily available or on hand at your local engine dealer for older engines.
GENERATOR TYPES & FEATURES
Generator sets produce either single or three phase power. Choose a single phase generator if you do not have any motors above five horsepower. Three-phase power is better for motor starting and running. Homeowners usually require single phase whereas industrial or commercial applications frequently require three phase power.
Three phase generators are set up to produce 120/208 or 277/480 or 347/600 volts. Single-phase sets are 120 or 120/240. Large heaters, stoves and dryers frequently use 240V volt power. 120V is the voltage available at your normal household electric outlets.
Generators are rated in either kVA (Kilovolt amperes) of kW (kilowatts), Kilo meaning 1000. kVA is always higher than the kW. All of our three phase water-cooled generators are rated with a power factor of 0.8 and single phase generators have a power factor of one.
GAS OR DIESEL?
Diesel generators while initially more expensive are frequently the best alternative due to their longevity and lower operating costs. Modern diesels are quiet and normally require much less maintenance than comparably sized gas (natural gas or propane) units. Fuel costs per kW produced with diesels is normally thirty to fifty percent less than gas units.