Expedited Shipping - US & Canada


We Buy & Sell Industrial Generators

Established 1981


Articles & Other Information

Generator Search

We Buy Used & Surplus Generators!

Get $$$ for your used power generation equipment

Cummins Onan Generators

Generators for Every Purpose

New Cummins 450 kW Indoor Generator
Anyone looking for assurance and convenience when it comes to standby and portable power generators does not have to look any farther than Cummins Onan. Primarily offering power generators for residential, commercial mobile, marine, and recreational vehicles, Cummins Onan power generators have been known as reliable and dependable for many decades.

Built by Cummins Power Generation, which is a subsidiary of Cummins Inc., the Cummins Onan brand has a strong history and a reputation that was built on the concept of high-quality and peace of mind.


No matter where the residential property is located, Cummins Onan residential power generators give homeowners an unparalleled level of comfort in knowing that if their power goes out, a reliable standby power generator is ready to kick into action on a moment's notice.

Cummins Onan residential backup power generators are compact, permanently installed, run on either natural gas or propane, and do not cause a disturbance to neighbors.

Commercial Mobile

When it comes to commercial mobile automobiles that are as important as fire trucks and other emergency vehicles, Cummins Onan power generators are a top choice. Built with quality and reliability in mind, Cummins Onan is one of the most trusted brands in the commercial mobile power generator sector.


New Cummins 200 kW Outdoor Generator
Offering incredibly innovative marine generator sets, Cummins Onan marine diesel generators are easy to use, self-monitoring, reliable, and not loud.

The Cummins Onan brand has been involved in the marine power generation industry for many decades, and has refined the design of its marine generators which allows boaters to feel safe and secure while on the water.

Recreational Vehicles

Anyone traveling in a recreational vehicle relies on the dependability of a power generator. Available in diesel, gasoline and liquid propane varieties.

Cummins Onan has been providing convenient power to RVs for many years. When traveling long distances, power generators are of the greatest importance, and Cummins Onan are convenient and provide dependability.

Backed by the Cummins name, the Cummins Onan brand offers power generators that are not only built to last, but also built with environmental factors in mind. Cummins Onan is highly regarded and trusted. Founded in 1920, Cummins is a brand that is here to stay with backup power that offers dependable solutions to residential, commercial mobile, marine, recreational vehicle and other sectors requiring standby and/or portable power applications.
>>Back to Articles & Info<<

Onan Generators History and Relation to Cummins

Generator Source has been proving industrial and commercial sales, rentals and service for nearly 40 years.  During this time we have we have have worked on and built experience with most generator set manufacturers. This artilce provides additonal insigtht and history on the Onan brand, and how everything is related to Cummins.  

Beginnings of Onan CorporationOnan 75 kW Generator Powered by Ford Engine

Minnesota native David W. Onan founded Onan Corporation. David was never fond of school and dropped out to support his family when his father passed away when he was 14. His first job was helping build a power plant for the Niagara Falls power and light company.   

His next move was to Reinhard Electrical Repair Department, where he supervised 50 mechanics that turned out 100 to 125 repair jobs per day. During World War I, he taught mechanics at the Dunwoody Institute in Minneapolis, and in his spare time, he worked on mechanical inventions. He was often called a mechanical genius by his peers.

During the 1900s, the automotive industry did not have the service it has today. The owner was expected to remove a failed part and send it in for repair or replacement. In the 1920s, David started his new company from his home, largely working in the evenings on tools and devices for the automotive industry. He created the following 12 manufacturing points for his company:
  1. Product acceptance
  2. Engineering
  3. Experimental research
  4. Tool and die excellence
  5. Production and assembly
  6. Production flow
  7. Final testing
  8. One product concentration
  9. Meeting a need
  10. Sales and service facilities
  11. Basic management
  12. Teamwork

Onan Ten-Lite Generator

In the late 1920s, the Ten-Light generator was introduced and sold for $99 plus $12.00 for ten 30-Watt light bulbs and the wiring it powered. The bulbs and wiring would be routed around the home and connected to the generator. This supplied electricity to rural homes that did not have access to utility power. It was a Direct Current (DC) generator. The first Alternating Current (AC) generator was marketed in 1929 and began the Onan generation history.     

Onan continued to grow in the generator business, expanding to supplying generators for recreational vehicles and the marine industry. They coupled with large engine manufacturers such as Ford and Cummins engine company. In 1992, Onan Corp became a fully owned subsidiary of Cummins Inc.

Generator Source has more than 38 years of generator experience. We are proud to stock Onan generators and accessories. For our line of in-stock products, go to Onan Generators.

Cummins/Onan Generators

Onan 250 kW Powered by Cummins Engines
Cummins Inc. is the world's largest designer and manufacturer diesel engines. The size of the engines range from 55 to 2700 horsepower and are used for on-highway vehicles, industrial equipment, and marine applications. Cummins industrial engines often power generators, and they utilize Onan-produced alternators (generator end). These units are often referred to as Cummins Onan generators.  

Cummins generators using the Onan alternator are branded Cummins Onan and remained that brand until 1992 when they purchased Onan. Cummins Industrial generators manufactured after 1992 may not bear the Onan brand name but do use the Onan alternator. These units were manufactured in the two popular design categories below.

Indoor Generator

An engine, alternator, and radiator are mounted on a framework called a skid. This is considered a complete generating unit but does need supporting our auxiliary systems. The fuel system generally consists of a primary fuel tank supplying a day tank that supplies fuel for the generator.  The radiator is commonly connected to a louver system for outside air. Exhaust must be routed through mufflers and to the outside.

Outdoor Generator

The same concept of engine alternator and radiator mounted on a framework is used. A fuel tank is installed within the confines of the framework and sized to accommodate the operation of the generator engine. An enclosure surrounds the generating unit. They can be sound attenuated and either weather resistant or weatherproof for harsh operating conditions. They are ready to be set on any level surface that will support their operational weight and connected to the building grid.

Emissions & Environmental Protection Agency (EPA)

Generators produced before 1992 do not meet the rigid requirements the EPA sets with the Tier 4 certification. However, these generators meet the requirements for emergency or standby use. The recent ruling by the California Air Research Board (CARB) allows these generators to be used for Power during Public Safety Power Shutoff events (PSPS). These events can run from hours to days to weeks.

Additional Equipment & Applications

Onan 260 Amp Automatic Transfer Switch
A generator is not the only piece of equipment in standby or an emergency power system. Generator output cables must be connected to a switching device. The manual switching device allows for the transfer of generator power to the grid, and isolates do utility power. When power is lost it, must be manually switched to the generator mode. After utility power is restored, the generator is shut down, and the switch is returned to normal position.

The Automatic Transfer Switch (ATS) is the most widely used switching device today. When utility power is lost, the below set of events happens:
  1. Generator is in automatic operation and receives a start signal. Engine starts and generator prepares to accept the load.
  2. ATS switches from utility power to generator power. Generator accepts the load.
  3. When utility power is restored the ATS switches to the normal mode and sends the generator a shut down command.
  4. The generator initiates shut down.

Recreational Vehicle (RV) Generators

Generator equipped recreational vehicles have the ability to go off the grid with all the conveniences of electrical power. Cummins has 80 years of experience in recreational vehicle generators. Today's Cummins Onan generators are the standard for quiet, reliable, innovative RV power.  

They come in a variety of sizes and fuel selections. The customer can select from diesel, gasoline, or liquid propane fueled generator engines. Technical advances such as remote start controls and automatic start systems allow a new level of convenience for powering your RV in off grid areas. The generators quietly operate to reduce noise pollution.

We have a large selection of both pre-owned and new generators. Preowned generators offer an initial purchase savings, and all must pass a 31-point inspection prior to sales. Our large supplier network allows us to offer crane and shipping services. Many times, we can arrange for shipping within 24 hours of purchase completion. Contact Us for more information or to get the ball rolling.     
>>Back to Articles & Info<<