
SEBU8088-06 127
Reference Information Section
Engine Ratings
Prime + 10% (Sta
ndby applications for a power
supply from a reliable utility) – This rating allows a
load that varies up to the Prime rating. An additional
ten percent is
allowed for the duration of the power
interruption. The normal load factor is up to 80
percent for 100 hours per year. A 100 percent load
is only allow
ed for 5 percent of the operating cycle.
The suggested application is Standby for a power
supply from a reliable utility.
Prime + 10% (Applications that are industrial,
pumping, construction, and cogeneration) – This
rating allo
ws a load that varies up to the Prime rating.
Thenormalloadfactorisupto80percentforan
unlimited number of hours per year. A load of 100
percent is o
nly allowed for 5 percent of the operating
cycle. The following applications are suggested:
industrial, pumping, construction, and cogeneration.
Standby – This rating allows a load that varies for
the duration of the power interruption. The normal
load facto
r is up to 80 percent for 100 hours per year.
A 100 percent load is only allowed for 5 percent of
the operating cycle. The suggested application is
Standby f
or a power supply from a reliable utility.
Load Management Peak Shaving Rating
Guidelin
es
Interruptable (Iso lated from the utility with a
Standby b
ase rating for load factors) – This rating
allows a load that varies for less than 12 hours per
day. The typical peak load factor is up to 80 percent
for less
than 500 hours per year. The peak operating
limit is a load factor up to 100 percent. A 100 percent
load is only allowed for 5 percent of the operating
cycle. T
he operating cycle for calculating the load
factors and the peak load limits is not to exceed six
hours. The operating cycle does not include the time
when th
e engine is not operating.
Interruptable (Iso lated from the utility with a
Prime b
ase rating for load factors) – This rating
allows a load that varies for more than 12 hours per
day. The typical peak load factor is up to 80 percent
for an u
nlimited number of hours per year. The peak
operating limit is a load factor up to 100 percent. A
100 percent load is only allowed for 5 percent of the
opera
ting cycle.
Curtailable (Connected to a utility with a special
base r
ating for load fact ors) – This rating allows a
constant load or a load that varies for less than six
hours per day. The typical peak load factor is up to
100 p
ercent for a maximum of 500 hours per year.
The peak operating limit is up to 100 percent load for
a maximum of 500 hours per year.
Curtailable (C
onnected to a utility with a
Continuous base rating for load factors) – This
rating allows a constant load or a load that varies for
more than six h
ours per day. The normal load factor
is up to 100 percent for an unlimited number of hours
per year. The peak load factor is up to 100 percent
for an unlimi
ted number of hours per year.
Industria l E
ngine Ratings
“IND A” (Continuous) – This rating allows operation
at the engine
’s rated load and speed for 100 percent
of the time without interruption or load cycling. The
engine may be operated at full load for 100 percent of
the d uty cyc
le. The following applications are typical:
pipeline pumping, ventilation, and applications that
are specified by the customer.
“IND B” – This rating is for service with power
and/or speed that is cyclic. The time at full load is not
to exceed 8
0 percent of the duty cycle. The following
applications are typical: irrigation with a normal pump
demand that is 85 percent of the engine rating,
mechanica
l pumping and/or drilling in an oil field, and
stationary plant air compressors.
“IND C” (In
termittent) – This rating is for service
with power and/or speed that is cyclic. The engine
can be operated continuously for one hour at the “C”.
This is fo
llowed by one hour of operation at the “A”
rating or below the “A” rating. Continuous power may
be supplied by engines with the “C” rating. However,
full load
operation is not to exceed 50 percent
of the duty cycle. The following applications are
typical: agricultural tractors, harvesters, combines,
off-hig
hway trucks, power for fire pumps, drilling for
blast holes, rock crushers with high torque rise, wood
chippers with high torque rise, and oil field hoisting.