Dado que estas son clasificaciones o sistemas de valoración que se usan en inglés, usaría 'sistema de valoración tipo prime,' es decir, aquella valoración usada cuando el generador opera con una carga variable por un período ilimitado.

#9 What is the difference between the many ratings?
Standby rating - The rating that is assigned to a unit to be used as an emergency backup source. Generator will produce the rated kW for a short amount of time. This is a very common rating of large standby power systems for facility backup power.

Surge rating - The rating at which a sudden temporary variation (surge) in current, voltage, or frequency can occur without harming or stalling the generator. This is the rating used by portable generator manufacturers. It can be very misleading if you are comparing this rating to commercial duty equipment such as a TigerPower PTO.

Continuous Standby rating - Refers to the rating that is assigned to a unit to be used as an emergency backup source with varied load. This generator will produce continuously at the rated kW at varied loads. This is the rating TigerPower uses for their PTO generators.

Continuous rating - The rating at which the generator can operate with a constant non varying load for an unlimited time. This is set by the manufacture and is the machines capability to produce “x” amount of power continuously if the load doesn’t change. This is a typical rating for large engine driven units used for peak shaving.

Prime rating - The rating at which the generator can operate with a varying load for an unlimited amount of time. (24/7/365) Used when the generator is the sole power supply.http://www.messicks.com/Articles/PTOGenerator.aspx