Generators For Sale

About Generators

Generators convert fuel into electricity, serving as a reliable primary power source in areas where electricity isn’t accessible, backup or standby power during an outage, or continuous power for a city, town, ship, or offshore oil rig. They range from small, 1-kilowatt portable generators to large-scale power plant generators capable of producing several megawatts of electrical power. From campgrounds to hospitals and backyards to construction sites, generators are widely used to provide electricity when and where it is needed.

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2023 Caterpillar D800 GC Stationary Generator

How Generators Work

A generator typically uses an internal combustion engine to power an alternator (generator end) to produce electricity. The engine and generator end combination is sometimes called a “generator set” or “genset.” The engine spins the alternator’s rotor inside its stator, where magnets and windings of copper wiring induce an electrical current via electromagnetism.

How To Buy A Generator

To make selecting the right new or used generator simpler, many manufacturers offer turnkey models made expressly for common applications, such as standby generators for homes and businesses. Several also provide wattage calculators and other tools to help you quickly determine how powerful a generator you need.

Factors to consider when you’re choosing a generator may include:

• How you plan to use the generator – whether you need backup power after a storm, prime power for a specific purpose, supplemental power during peak hours (load management), or continuous power for the local grid
• Power rating for wattage and duration needed – total wattage is expressed in ekW (electrical kilowatts) or kVA (kilovolt-amperes), while an example of duration is indefinitely at 70% of its prime power rating or temporarily at its full standby power rated load
• Electrical specifications required – such as 60 Hertz power in North America, single-phase or three-phase output, and 120/240/480 voltage outlets
• Fuel type – gasoline (typical on smaller generators), diesel (for larger generators), natural gas, LP (liquid petroleum) gas, propane, or duel-fuel capability for running on either gasoline or propane
• Desired run time – how long you need the generator to run before refueling
• Average load factor – how much of the generator’s capacity will be required of it on average, such as 70% for a standby model
• Inverter availability – used to provide power stable enough for computers and other electronics
• Acceptable noise level – such as a quiet or super quiet backup generator for a suburban home
• Safety features – such as circuit breakers, ground fault circuit interrupters (GFCIs), electric shock prevention, and a carbon monoxide sensor that shuts off the generator
• Cost – including the generator itself, installation, and operating costs over time

Towable Generators

Towable generators are trailer-mounted units, and while many are small enough to pull with a standard pickup truck, some are large enough to require a semitruck. They can provide power on jobsites to run lights, tools, and other equipment away from the grid or deliver standby power during outages.

Stationary Generators

A more permanent alternative to towable generators, stationary generators typically offer higher power ratings for standby or prime power duty. Total power can range from 5 kW for a small home standby generator to 3,000 kW for larger industrial generators. Stationary generators, along with components such as renewable energy sources and battery storage systems, can also play a part in microgrids.

Power Plant Generators

Power plant generators from Caterpillar and other manufacturers are large, stationary models that can supply the needs of a major factory or homes and businesses in a city, town, or region. Most power plant generators use either large reciprocating engines or steam turbines. They generally burn traditional fuels, such as diesel, coal, heavy fuel oil, or natural gas, although some models can be powered by renewable sources, such as wind, wave, hydroelectric, or solar energy.

Marine Generators

A marine generator operates like a power plant model but is designed for use aboard boats, ships, and other types of watercraft. Unlike a boat’s main engine, designed primarily for propulsion, a marine generator handles the load of the various electrical equipment on the vessel, such as lights, navigation and communication equipment, and heating, ventilation, and cooling (HVAC) systems.

PTO Generators

Power take-off (PTO) generators get mechanical power from a shaft connected to the power take-off of a tractor, hence their “tractor generators” nickname. They’re popular with farmers, ranchers, dairy operations, and other businesses for the mobile power they provide and for their ability to keep home or farm operations running when the power is out.

Home Standby Generators

Home standby generators provide backup energy when power lines go down in regions prone to hurricanes, wildfires, ice storms, and other natural disasters. These generators are permanently installed outside the home and are designed to activate automatically when utility power is interrupted.

Depending on their rated capacities, home standby generators can supply electricity to an entire house's large appliances, heating and cooling systems, microwaves, televisions, lights, and more for days or weeks. They can prevent freezing pipes, food spoilage, overflowing sump pumps, and other outage hazards.

Portable Generators

Though many generators are movable, those termed portable generators can be physically carried or pulled along on wheels. Portable generators provide power when electricity goes out or in remote areas or event venues without reliable electricity. Contractors often use these generators to run power tools throughout the workday or on farms or acreages to supply power to work lights, heaters, and other equipment.

Compact Recreational Generators

While smaller and easier to move than other generators, compact recreational generators are considered more of a short-term power source than portable and home standby models. Generally suitable for camping, RVing, fishing, and tailgating, these generators provide enough power for mobile devices, smaller appliances such as slow cookers, and flatscreen TVs.

Many portable recreational generators include an inverter to produce stable, quiet power for sensitive electronics economically. Higher-end units may support powering RV air conditioners and larger appliances. For lighter duty, like recharging devices and powering a CPAP machine while tent camping, battery-only units may meet your needs.

Generator Kilowatt Ranges & Standby Power Ratings

Wattage calculators, available on several manufacturer websites and elsewhere online, help you determine how many kilowatts of power you need to keep your equipment, appliances, and other electrical items running simultaneously. Below is a general overview of use cases for various kilowatt ranges.

You can determine how many kilowatts of power you need by using a wattage calculator or generator size calculator. Calculators help you determine the total wattage your equipment, or important appliances require while running simultaneously. They also generally add some extra capacity for emergencies and to account for the additional power many devices require on startup. This added margin is also necessary so the generator doesn’t have to run constantly at 100% capacity, reducing wear and tear.

Here’s a very general overview of use cases for various kilowatt ranges:

• 1- to 10-kW generators – small home backup power for essential appliances (lights, refrigerator, minor electronics) and/or prime power for recreational vehicle (RV) and tailgate appliances (microwave, air conditioner, mini fridge, TV), as well as small power tools (saws, drills, grinders, sanders
• 11- to 20-kW generators – Medium home backup for more demanding home appliances as needed (electric range, A/C, vacuum cleaner, residential refrigerator, electric fireplace, water heater, deep freezer, home theater components), small business equipment (printers, copiers, computers), and more demanding tools for construction (welders, air compressors)
• 21- to 50-kW generators – Large home backup for multiple demanding appliances running simultaneously (electric heating, A/C, oven, stovetop, fridge, freezer), small commercial business offices, and heavier construction equipment (tower cranes, pumps)
• 51- to 100-kW generators – Data centers (servers and network equipment), commercial business buildings, and mission-critical equipment in industrial facilities
• 101- to 500-kW generators – Multiple commercial buildings, critical hospital equipment, large data centers, and medium industrial facilities
• 501- to 2,000-kW generators – Power company failover protection and large commercial complexes, factories, and manufacturing facilities
• 2,001-kW and greater generators – Primary power generation and large-scale industrial complexes

Special Generator Applications

PowerSystemsToday.com also gives you easy access to new and used generator listings for specific applications and needs:

Quiet Generators

“Silent” or “quiet” generators produce a level of sound resembling the volume of a normal conversation, which is generally considered to be about 60 decibels that are A-weighted, or focused on the volume of frequencies the human ear hears best.

Super Quiet Generators

Some compact generators and models in enclosures are described as “super quiet,” such as the Honda EU1000i (in the Honda EU series) at 42 to 50 dBA. For reference, the noise level of a quiet office is generally considered to be approximately 50 dBA.

Natural Gas Generator Sets

These have the advantages of low operating costs, reduced noise, and the ability to connect to either a tank or a gas line for uninterrupted operation (although natural gas utilities may not be available if the local electrical grid is down).

Diesel Generator Sets

Relatively larger units powered by diesel engines, diesel generator sets tend to offer a much longer lifespan, lower maintenance costs, and lower cost per kilowatt.

RV Generators

RV or camper generators are portable and compact recreational generators that power recreational vehicle appliances and electronics.

Commercial Generators

Bigger and sturdier than household standby generators, commercial units provide more power to keep businesses running until the power is restored.

Inverter Generators

These produce stable power for sensitive electronics such as computers, albeit with less power output than a traditional generator. Inverter gensets can also run at a lower engine speed, using less fuel and producing less noise.

Liquid Cooled Generators

These generators have midsize and large engines that use liquid coolant, a pump, and a radiator to dissipate waste heat.

Air Cooled Generators

These have smaller engines that can shed their lower heat output through metal fins without the maintenance requirements of a liquid cooling system.

CARB Compliant Generators

Generators in this category meet state regulations from the California Air Resources Board.

EPA Certified Generators

Generators in this category meet Federal emissions standards from the Environmental Protection Agency, such as with Tier 4 Final diesel engines.

Military Generators

Sometimes available as surplus, military generators are durable, rugged, and usable under extreme conditions. Manufacturers include Alaska Defense, Cummins, Generac, and Fermont.

Where To Buy & Finance Generators

Whether you’re looking for backup power for your business or a smaller generator for outdoor recreation, explore PowerSystemsToday.com to find new and used generators for sale.

Popular manufacturers include Atlas Copco, Caterpillar, Cummins, Generac, Giga Power, Honda, Kohler, Multiquip, and Multiquip WhisperWatt.

Looking for financing solutions? CurrencyFinance simplifies generator financing by offering tailored rates and terms, including options for buyers with less-than-perfect credit.