voltage conditions attributed to a fault or to
momentary dips or excursions (transients) in normal
or preferred power source. Time delay before
monitored source override should exceed associated
circuit breaker tripping time and normal system
voltage instability periods. Minimum of 1 second is
recommended. Where utility type power source is
used and application is standard, monitoring devices
should drop out at 85 percent of nominal value and
pick up at 90 percent. Where precise power is
monitored, protection should be specified with
monitoring devices set to pick up at 95 and drop out
at 90 percent of nominal. In applications requiring
closer regulation, solid state or microprocessor
arrangement may be used with pickup and dropout
response adjusted as close as 2 percent
differential. However, for these applications a
redundant uninterruptible power supply should be
considered.
Delete generator reference if not required.
**************************************************************************
Time delay to override monitored source deviation shall be adjustable from
[0.5] [_____] to [6] [_____] seconds and factory set at [1] [_____]
second[s]. ATS shall monitor phase conductors to detect and respond to
sustained voltage drop of [25] [15] [_____] percent of nominal between any
two [normal] [preferred] source conductors and initiate transfer action to
[alternate] [emergency] source and start engine driven generator after set
time period. Pickup voltage shall be adjustable from [85] [_____] to 100
percent of nominal and factory set at [90] [_____] percent. Dropout
voltage shall be adjustable from [75] [_____] to [98] [_____] percent of
pickup value and factory set at [85] [_____] percent of nominal.
2.1.2
Transfer Time Delay
**************************************************************************
NOTE: Use nonzero setting where multiple ATS
require staggered application of load steps to
alternate or emergency source.
**************************************************************************
Time delay before transfer to [alternate] [emergency] power source shall be
adjustable from [0] [_____] to [5] [_____] minutes and factory set at [0]
[_____] minutes. ATS shall monitor frequency and voltage of [alternate]
[emergency] power source and transfer when frequency and voltage are
stabilized. Pickup voltage shall be adjustable from [85] [_____] to 100
percent of nominal and factory set at [90] [_____] percent. Pickup
frequency shall be adjustable from [90] [_____] to 100 percent of nominal
and factory set at [90] [_____] percent.
2.1.3
Return Time Delay
Time delay before return transfer to [normal] [preferred] power source
shall be adjustable from [0] [_____] to [30] [_____] minutes and factory
set at [30] [_____] minutes. Time delay shall be automatically defeated
upon loss or sustained undervoltage of [alternate] [emergency] power
source, provided that [normal] [preferred] supply has been restored.
SECTION 16410A
Page 10
Previous Page
