In the Know

Generator Set Ratings | What You Need to Know

Choosing the right generator set can be a confusing and a time consuming process. Generator set ratings have been implemented to help simplify the process. The ratings meet various run-time and power criteria based on the generator set's application.

According to Ray Marfell's blog, "What You Need to Know About Generator Set Ratings," he explains, "To provide consistency across manufacturers and industries, and to improve communication and understanding between the manufacturer and the customer, the International Standards Organization (ISO) developed a standard set of rating definitions."

For example, ISO 8528 is a minimum standard in generator set ratings that refers to gas and diesel generator sets for land and marine use. Some manufacturers still use their own variations of genset ratings despite the standardizations.

Caterpillar has six basic generator set ratings - Emergency Standby Power (ESP), Standby, Mission Critical Standby, Continuous, Prime and Load Management (LTP). These ratings comply with the minimum criteria, but are not identical to the ISO 8528 standards.

Efficiency and effectiveness directly impact by generator set ratings based on its application. Additionally, engines that have an aggressive rating can have unexpected downtime and increased wear and tear. Note that conservative ratings do not necessarily imply the best value.

Be sure to consider these factors when you determine the right generator set rating for your project.

  • What is the average load factor?
  • What is the maximum required load? 
  • What is the typical load variation?
  • How many hours per year will the generator sets typically run?
  • Will the generator sets be run isolated from or in parallel with the utility?
  • What are my maintenance and contingency plans during an extended outage?

Read the blog. Contact a Hawthorne Power Systems representative for more information.

San Diego - Power

Steve Jamison

Power Systems Sales Manager

858.376.6821 office

858.688.0083 mobile

Hawaii - Power

Cliff Yuen

Power Systems Sales Manager

808.676.0322 office

808.349.7767 mobile