motor starting requirements represented as starting
kVA, and the non-linear loads to be served. This
information should be included in the
engine-generator set parameter schedule or on the
drawings for each different unit provided. For this
application service load is the peak estimated
loading to be placed on the engine generator set.
Peak demand calculation provides a figure from which
to determine the service load. When specifying a
genset be sure to specify what the peak load is and
how much is continuous.
Power Factor. Commercial genset power ratings are
usually based on 0.8 power factor. Select 0.8
unless the application requires one more stringent.
Motor Starting Load. Motor starting requirements
are important to properly size engine generator sets
because the starting current for motors can be as
much as six times the running current, and can cause
though the genset has been sized to carry the
running load. The designer must analyze the motor
loads to determine if the starting characteristics
of a motor or a group of motors to be started
simultaneously will cause objectionable genset
performance. Provide a starting kVA value for the
largest motor or combination of motors to be started
simultaneously. An increase in the size rating of
the genset may be necessary to compensate for the
inrush current. This assists the genset supplier in
properly sizing the engine generator set.
Maximum Speed. The maximum allowable speed is 1800
RPM. If there is no specific requirement or user
requirement for slower speed machines, select 1800
RPM.
Heat Exchanger Type. Fin-tube exchangers
(radiators) are the predominate method of cooling.
Specify either a fin-tube or a shell-tube heater
exchanger for each engine-generator set. Heat
exchangers located remote from the engine-generator
set (i.e., not mounted on the engine-generator set
base) shall be shown on the project plans, including
the power source for associated fans and pumps.
Governor. The type of governor to be used on each
engine generator set should be identified as
isochronous or droop on the engine-generator set
parameter schedule. Isochronous governors hold
frequency at the setpoint frequency (within
bandwidth) for all steady state loads from 0 to 100
% load and are required for applications where
severe demands are made on voltage and frequency
regulation. Droop governors allow frequency to
droop to the specified percentage proportional to
steady state loads from 0 to 100% load and are
generally acceptable for general purpose and
SECTION 16264A
Page 15
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