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|  DOE-STD-3003-2000
equipment ratings for continuous operation,
typically 10% and 2% respectively. The
f.
The load profile (the time
EG system full load shall be within the
sequence and duration of load
CONTINUOUS RATING of the EG. The EG
application) including the change
shall have the capability to handle the load
in load currents resulting from the
power factor during loading and steady-state
extremes of allowable voltage and
operation. SHORT-TIME RATING overload
frequency variations. To the
specifications shall not be exceeded.
extent practical, the application of
loads should be at known time
5.2.1.3 Engine cooling. The EG should
intervals. The loading sequence
shall ensure that random loads
be provided with a self-contained cooling
cannot occur in a manner to
system. If self-cooling is not available, the EG
overload the EG. "Permissive," as
shall be able to operate without overheating
opposed to "demand," start
damage or trip for the time required to
signals shall be evaluated to
activate an auxiliary cooling system to ensure
ensure the loading profile is not
EG cooling. Refer to NFPA 110 for additional
compromised and to identify
guidance.
random loading problems.
Automatic loading may be limited
5.2.1.4 HOT RESTART. EGs should
to the necessary safety or other
have the capability for immediate HOT
important loads.
RESTART upon shutdown at full load
temperature conditions (after it has operated
g.
Conditions of load transfer
at full load for at least 2 hours).
needed between the normal
source and EG (unloaded bus,
5.2.1.5 EG ratings. Most EGs will have
automatic SYNCHRONIZATION,
continuous and overload ratings. Typical EGs
manual SYNCHRONIZATION)
will have more than one overload rating.
and including consideration of
These ratings shall accommodate any
change between ISOCHRONOUS
overload transient that occurs during
and DROOP MODE of operation
sequence loading of equipment or a
momentary overload that could occur through
h.
Potential effect of failures or
manual action during testing. The light- and
inadvertent actuation of
no-load rating shall accommodate the
equipment such as water spray
starting and loading sequence. If the EG
from fire protection equipment.
must be operated under light load longer
Refer to NFPA 110 for additional
than manufacturer's specifications, the
guidance.
manufacturer shall be consulted as to what
precautions to take to rectify the accumulated
5.2.1.2 Starting and loading. The EG
detrimental effects of low-load operation
and/or how to prevent such detrimental
shall be capable of starting, accelerating, and
effects. Refer to IEEE 387 for additional
loading within the time required by the
guidance regarding light loading.
demands of the equipment/system being
supplied. This requirement is discussed in
5.2.1.6 Vibration. Critical speeds
IEEE Std 387. Voltage and frequency shall
be maintained during the loading sequence
associated with excessive vibrational
such that equipment will operate without
stresses shall not occur within 5% of the
malfunction. Typically, the frequency should
normal operating speed of the machine.
be > 57 Hz and voltage > 75% of nominal.
Refer to IEEE Std 387 for additional
Subsequently, the steady-state operating
guidance.
voltage and frequency to the loads should be
within the manufacturer's guaranteed
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