Download SECTION 16204

SECTION 16204
AUTOMATIC TRANSFER & BYPASS-ISOLATION SWITCHES
204.01
GENERAL
A.
Manufacturer
Acceptable manufacturers shall be ASCO 7000 Series, Zenith, or
Onan.
B.
Material
The materials and equipment used in the construction of the transfer
switch covered by this specification shall be new, of the highest quality,
and of the type recognized by the industry for use in this type of
equipment.
C.
Rating
1.
The ATS/BPS shall be rated to close on and withstand the
available RMS symmetrical short circuit current at the ATS/BPS
terminals with the type of overcurrent protection as indicated
below
Switch Rating (A)
600 - 800
1600- 4000
D.
2.
The switch shall be 480 volt, three (3) pole solid neutral switches.
3.
The switch shall be listed under Underwriter’s UL-1008
requirements and be labeled in accordance with that standard's
1-1/2 and 3 cycle, long time ratings.
Description
1.
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Fault Current Rating (RMS Sym. kA)
65
100
The transfer switch shall be electrically operated & mechanically
HELD. The Automatic transfer and bypass-isolation switch
(ATS/BPS) shall consist of an inherently double-throw power
transfer switch mechanism and a microprocessor controller to
provide automatic operation. Electrical operation shall be
accomplished by a momentarily energized single solenoid
operating mechanism which receives power from the source to
which the load is being transferred. The transfer switch shall be
capable of transferring successfully, in either direction, with 70%
of rated voltage applied to the switch terminals.
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2.
The normal and emergency contacts shall be positively
interlocked mechanically and electrically to prevent simultaneous
closing. Main contacts shall be mechanically locked in position in
both the Normal and Emergency positions, without the aid of
permanent magnets, latching solenoids, or motor operators.
Interlocked molded case circuit breakers or contactors are not
acceptable.
3.
The transfer switch shall be equipped with a manual operator that
is designed to prevent injury to the operating personnel, if the
electrical operator should suddenly become energized during
manual transfer.
4.
The manual operator shall be quick-make, quick break with a
lockable cover. A keyed transfer switch operator disconnect
switch (maintained) type shall be included. Disconnect switch
shall have red indicating lamp to indicate "ATS operator disabled."
5.
The transfer switch shall be equipped with a voltage selection plug
making it suitable for operation on any voltage from 208 through
600Vac, by placing the voltage election plug in the proper voltage
receptacle.
6.
A two-way bypass-isolation switch shall provide manual bypass of
the load to either source and permit isolation of the ATS from all
source and load power conductors. All main contacts shall be
manually driven. Separate bypass and isolation handles shall be
utilized to provide clear distinction between the functions.
7. The isolation handle shall be provide three operating modes:
"Closed," "Test," and "Open". When the isolation switch is in the
"Test" or "Open" mode, the bypass switch shall function as a
manual transfer switch.
D.
Auxiliary Equipment/Features
The ATS/BPS control system shall contain, but not be limited to,
equipment required to perform the following functions:
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1.
Monitor each ungrounded line with a calibrated dial, adjustable
voltage, solid state UNDERVOLTAGE SENSOR for sensing a
decrease of voltage below a set point, or a loss of voltage on any
phase of the normal power source. Voltage sensors shall be
temperature compensated for 2 percent maximum deviation over
the temperature range -25F (-32C) to 175F (+79C).
2.
Signal the generator set to start, in the event of a power
interruption. A solid state TIME DELAY START (adjustable from
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AUTOMATIC TRANSFER & BYPASS-ISOLATION SWITCHES
0.5 to 10 seconds) shall delay this signal to avoid nuisance
startups on momentary voltage dips or power outages.
3.
Transfer the load to the generator after it reaches proper voltage
and frequency. A solid state TIME DELAY TRANSFER
(adjustable from 0.5 to 10 seconds) shall delay this transfer to
allow the generator to stabilize.
4.
Retransfer the load to the line after normal power restoration. A
TIME DELAY RETRANSFER (adjustable from 0 to 30 minutes)
shall delay this transfer to avoid short term, normal power
restoration.
5.
Provide an automatic RETRANSFER TIME DELAY BYPASS to
retransfer the load from the generator set to normal source, if
generator set output interrupts after normal source restores
voltage.
6.
Signal the turbine/engine generator to stop after load retransfer to
normal source. A solid state TIME DELAY STOP (adjustable from
0.5 to 5 minutes) shall permit engine to run unloaded to cool down
before shutdown.
7.
Provide NORMAL-TEST SWITCH to select “Normal” automatic
operation or to start and run generating set for test purposes.
Works in conjunction with WITH LOAD-WITHOUT LOAD
SWITCH.
Provide a WITH LOAD-WITHOUT LOAD SELECTOR SWITCH to
select test or exercise as follows:
8.
a. “Without Load”, the generator set runs unloaded.
9.
b. “With Load”, the automatic transfer switch transfers load to
generator set, after time delay, the same as it would for a
normal source interruption.
Provide an in-phase monitor built-in total controller. The in-phase
monitor (27) shall control transfer so that motor load inrush
currents do not exceed normal starting currents, and shall not
require exterior controller power sources.
10. Provide a keyed three position switch to simulate normal source
failure (test) and bypass time delay on retransfer to normal.
11. The controller shall provide an internal engine exerciser. The
engine exerciser shall allow the user to program up to seven
different exercises routines. At the end of the specified duration
the switch shall transfer the load back to the specified cool down
period. A 10-year life battery that supplies power to the real time
clock in the event of a power loss will maintain all time and date
information.
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AUTOMATIC TRANSFER & BYPASS-ISOLATION SWITCHES
F.
204.02
Enclosure
a.
The ATS/BPS shall be furnished in a NEMA Type 1 enclosure
unless otherwise noted.
b.
Transfer switch shall be rated for continuous duty, when installed
in a nonventilated enclosure constructed in accordance with
Underwriters Laboratories, Inc. Standard UL-508.
QUALITY ASSURANCE AND APPROVAL
A.
Factory Testing
1.
The manufacturer of the automatic transfer and bypass-isolation
switches shall verify, as a condition for approval, that his switches
are listed by Underwriters Laboratories, Inc., Standard UL-1008.
2.
The manufacturer shall include post endurance temperature rise
tests to verify the ability of the transfer switch to carry full-rated
current after completing the overload and endurance tests, when
conducting temperature rise tests for Paragraph 17 UL-1008.
The ATS/BPS must have 3-cycle short circuit withstand capability
in addition to the above, and in excess of the UL-1008 minimum
requirement.
3.
The manufacturer must produce certified test reports from an
independent testing laboratory to establish conformance with the
above, and to verify that identical samples have been subjected to
three (3) phase short circuit currents at 480V AC, for a minimum
of three (3) cycles duration, without contact damage or contact
welding and without the use of current limiting fuse protection.
Oscillograph traces are to be supplied to verify that the test
parameters have been met.
4.
Assemble all test data in booklets for submittal.
Jobsite Testing
The ATS/BPS shall be tested at the Jobsite under the supervision of a
representative of the manufacturer, upon completion of the installation.
Testing shall include checking of all automatic controls for proper
functioning, and a load test. Operating personnel will be instructed in
the proper operation and maintenance of the unit.
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