Reference Information
Section
Engine Ratings
i00727327
Engine Rating Conditions
SMCS Code: 1000
All engine ratings are in compliance with the following
standard ambient air conditions of “SAE J1349”:
• 99 kPa (29.3 inches of Hg)
• 30 percent relative humidity
• A temperature of 25 °C (77 °F)
Ratings relate to the standard conditions of
“ISO8665”, of “ISO3046/1”, of “DIN6271”, and of
“BS5514”.
The engine ratings are based on the following fuel
specifications:
• Low heat value (LHV) of the fuel of 42 780 kJ/kg
(18,390 Btu/lb) at 29 °C (84 °F)
• Gravity (API) of 35 degrees at 15 °C (60 °F)
• Specific gravity of .849 at 15 °C (60 °F)
• Density of 850 kg/m
3
(7.085 lb/US gal)
The engine ratings are gross output ratings.
Gross Output Ratings – The total output capability
of the engine that is equipped with standard
accessories.
Standard accessories include the following
components:
• Oil pumps
• Fuel pumps
• Water pumps
Subtract the power that is required to drive auxiliary
components from the gross output. This will produce
the net power that is available for the external load
(flywheel).
i00681146
Engine Rating Definitions
SMCS Code: 1000
Ratings for Generator Set Engines
The engine ratings that are listed below have a
manufacturing tolerance of plus three percent or
minus three percent.
Standby Rating
• Typical load factor of 60 percent or less
• 100 typical operating hours per year
• Typical applications with standby service for
building services with an enclosed environment
• 80 percent typical peak demand of the standby
rated kW
• 100 percent of the rated kW for the duration of an
emergency outage
Prime Rating
• Typical load factor of 60 percent to 70 percent
• No limit to typical operating hours
• Typical peak demand at 100 percent of the
continuous rated kW for less than 10 percent of
the total operating hours
Some typical applications include the following
operations:
• industrial
• pumping
• construction
• peak shaving
• cogeneration
NOTICE
Operating a generator set engine above the rating
definitions will result in a shorter engine service life
before overhaul.
SEBU7125-13
153
Reference Information Section
Engine Ratings
To Next Page
Loading...