SECTION 16460
DRY-TYPE TRANSFORMERS
PART 1 GENERAL
1.01
A.
SUMMARY
Related Sections:
1.
2.
1.02
A.
1.03
16120 - Wires and Cables.
16450 - Grounding.
SYSTEM DESCRIPTION
Performance Requirements: Materials shall bear Underwriters
Laboratories (UL) labels.
SUBMITTALS
A.
Submit manufacturer's
before starting work.
B.
Submit test data for transformers as requested.
1.04
A.
catalog
cuts
and
technical
data
QUALITY ASSURANCE
Dry type transformer installation shall comply with NFPA 70
National Electrical Code - 1999 (NEC).
PART 2 PRODUCTS
2.01
A.
MANUFACTURERS
Dry Type Transformers:
1.
2.
3.
4.
2.02
A.
General Electric Corp.
ITE.
Square D.
Westinghouse.
EQUIPMENT
Rating:
1.
Transformers shall be ventilated dry type, 3 phase, 60
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2.
3.
2.03
A.
DESIGN AND CONSTRUCTION
Core and coil assembly shall be vacuum impregnated for
maximum resistance to moisture and shall be mounted on
vibration isolation pads.
1.
2.
3.
B.
Hertz, 480 volts delta primary and 208Y/120 volts
secondary, with four 2-1/2 percent FCBN taps and two 21/2 percent FCAN taps. KVA rating shall be as shown on
drawings.
Transformer insulation shall be Class "H", 220 degrees
Centigrade insulation systems and shall be rated for
operation (150 degrees C. rise above 40 degrees C.
ambient). Insulating materials shall be according to
NEMA ST20 standards.
Transformer sound level shall not exceed following
values when measured according to ANSI C89.2-1974: 9
KVA to 45 KVA-45 DB, 50 to 150 KVA-50 DB, 150 to 300
KVA-55 DB.
Transformers shall be provided with a drip-proof,
rodent-proof, enclosure, having a durable finish and a
rustproof diagrammatic nameplate.
Wiring compartments shall have adequate space for
terminating cables and shall be front connected for
easy accessibility.
Where transformers are exposed to the weather, provide
weather shields.
Core of the transformer shall be of high quality, coldrolled, grain oriented steel, annealed by manufacturer for
low loss and exciting current.
1.
2.
3.
Laminations shall be formed to eliminate burrs and
annealed to reduce losses to a minimum.
Winding conductors shall be annealed and insulated by
transformer manufacturer.
Conductor surfaces shall be free from slivers, burrs,
and other irregularities.
PART 3 EXECUTION
3.01
A.
INSPECTION
Do not proceed with the work of this section until
conditions detrimental to the proper and timely completion
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Project No.
M-DCPS MASTER
SPECIFICATION GUIDELINES
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16460 - 2
of the work have been corrected in an acceptable manner.
3.02
INSTALLATION
A.
Dry type transformers shall be installed by Contractor
according to manufacturer's instructions in rooms assigned
for the installation of equipment.
B.
Transformer enclosures and secondary neutral shall be
securely grounded to a cold water pipe, 3/4" diameter by 10
feet long buried in direct contact with the earth, with a
copper conductor sized according to NEC Table 250-94.
C.
Dry type transformers shall be floor mounted or bracket
mounted as shown on drawings. Transformers shall be bolted
to floor if floor mounted and shall be bolted to steel
angles if bracket mounted, or as shown on drawings. Provide
a 3 inch high concrete pad under floor mounted
transformers.
D.
Transformers shall be vibrationally isolated from the
building structure by means of double neoprene pads (DNP),
in addition to the vibration isolation built into the
transformer. Neoprene shall be similar to Mason Industries
Type W, 40 durometer minimum or sized for proper weight
load.
E.
Conduit connections to the equipment shall be made with
flexible conduit, loosely installed.
F.
Dry type transformers shall be installed
compartment to front to allow removal.
G.
Maintain manufacturers recommended clearness from walls or
surfaces to allow adequate ventilation. In no case shall
the transformers be installed less than 6 inches from any
wall.
with
wiring
END OF SECTION
Project Name
Project No.
M-DCPS MASTER
SPECIFICATION GUIDELINES
March 03
16460 - 3