Helpfully, ISO-8528-1:2005 defines basic generator set rating categories based on four operational
categories: Emergency Standby Power (ESP), Prime Power (PRP), Limited-Time Running Prime (LTP) and Continuous Power (COP). In each category, a generator set’s rating is determined by maximum allowable power output in relation to running time and the load profile.
Incorrectly using these ratings can lead to lower generator life, invalid warranties and in some instances terminal failure.
So What is Limited Time Power (LTP)? ISO-8528-1 states that a LTP-rated generator set must provide power for up to 500 hours per year with the maintenance intervals and procedures being carried out. The LTP rating dictates no requirement for overload capacity. ISO-8528-1 explains the 24-hour average load factor to be up to the full LTP rating.
If you are using the generator for more than 500 hours per year? Look at the other ISO 8528-1 Ratings:
Emergency Standby Power (ESP)
Continious Power (COP)
Prime Power (PRP)