Generator set ratings are operating values that manufacturers provide for users, telling them how much power an engine can produce under certain conditions. These ratings are usually found on a metal plate affixed to the generator.
The International Standards Organization, an independent non-governmental organization, develops the recommended generator ratings for manufacturers to use. The standards listed under ISO-8528-1 apply to reciprocating internal combustion (RIC) engines used in generators for land and marine applications, with the exception of aircraft, land vehicle propulsion, and locomotives.
Several factors are considered when setting generator ratings, including:
- The engine’s ability to manage the electrical load
- Duration of the load
- Expected life cycle of the generator
- Mean time between overhauls (how long the engine can operate under average conditions before maintenance)
- Ambient conditions (such as climate and altitude)
- Manufacturer’s maintenance program
Generator ratings are useful tools to help customers select the right equipment for their needs. They’re also important guidelines for proper use of the equipment. Using a generator beyond its rating capacity can have serious consequences, such as system failure, voiding of the manufacturer’s warranty, and longer and pricier repairs. By the same token, using a generator according to its rating capacity can result in a longer lifespan for the equipment and a lower overall cost of ownership for the customer.
Here is a breakdown of the most common ISO generator set ratings.