a.
Three-phase normal source voltage sensing circuit with adjustable
dropout, 75-93 percent of nominal, and pickup, 85-100 percent of
nominal.
b.
Engine starting control contacts with adjustable commit-to-start delay
circuit, 0.5-6.0 seconds.
c.
Voltage/frequency sensing circuit, set for 80 percent of nominal, for
enabling load transfer to emergency source.
**************************************************************************
NOTE: Provide transfer to emergency source time
delay for the transfer switches requiring
delayed-automatic operation.
**************************************************************************
[d.
Transfer to emergency source time delay for transfer switches as
indicated, adjustable 0-5 minutes.]
e.
Re-transfer to normal source time delay, adjustable 1-30 minutes.
f.
Programmable exerciser to allow automatic starting of the generator set
and subsequent load transfer. Exercise periods shall be selectable for
1 to 24 hours per day for 0 to 7 days a week.
**************************************************************************
NOTE: When the transferred load includes motors
(over 50 HP or over 5 HP without significant
resistive loads), select the following option.
**************************************************************************
[g.
Adjustable time delay transition or in-phase monitor feature for
indicated transfer switches to allow safe transfer of highly inductive
loads between two non-synchronized sources.]
][2.1.2.2
Controls for Generator - Generator Source Automatic Transfer
Switch
**************************************************************************
NOTE: The following paragraph is intended for use
when a second automatic transfer switch is to be
used to select between two generators in a three
source (utility-generator-generator) system.
**************************************************************************
Provide all necessary controls to start both generator sets upon loss of
the normal utility source, transfer the load to the first generator set to
reach rated voltage and frequency, shutdown the second generator set upon
transferring the load to the first generator set, restarting and
transferring the load to the second generator if at any time the first
generator set fails, re-transfer the load when the normal (utility) source
returns, and shut down the generator set. The switch shall include the
following control features;
a.
Engine starting control contacts.
b.
Voltage/frequency sensing circuit, set for 80 percent of nominal for
enabling load transfer to emergency source.
SECTION 16410N
Page 8
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