After the application has been defined and the welding process has been selected, the next step is to choose the engine. Diesel, gasoline or liquid propane gas (LPG) are the choices. A diesel engine offers better fuel economy than a gasoline engine, and diesel fuel does not ignite as easily as gasoline. Refineries almost always require diesel-fueled machines rather than gasoline-fueled machines. Another consideration for large jobs is whether the fuel is being supplied at the job site. If so, it is usually diesel, but whatever the fuel, the cost savings will usually determine the engine choice.
Gasoline engines are sometimes preferred in cold weather climates because they start more easily without extra starting aids, such as ether start kits and winterized fuel for colder weather.
LPG is much less common, but becomes an important alternative choice when diesel and gasoline exhaust emissions are not permitted for indoor applications.
A spark arrester may also be required in forest and oil service areas.
Sometimes the need for portability will be the main factor in equipment selection. If an engine-driven welder needs to be carried or lifted to a work area, having a small gasoline stick welder will normally be the best answer.
AC Generator Power
AC power is sometimes required on the jobsite for grinding welds or for lights when working at night. Normally, 3,000 watts of AC generator power is plenty of power for these applications. Ground Fault Circuit Interrupters (GFCIs) are recommended and may be required. An AC TIG welder or plasma cutter will require more power - typically 8,000 watts minimum.
Product literature published by welding equipment manufacturers provides additional information that cannot be covered here in detail. Company sales representatives and the customer service departments are also excellent sources of information for technical questions on applications and products.