SECTION 16460 - TRANSFORMERS PART 1 - GENERAL 1.01 RELATED DOCUMENTS A. General: Drawings and general provisions of the Contract, including General and Supplementary Conditions and Specification Section 16010, apply to work specified in this section. 1.02 DRY-TYPE TRANSFORMERS A. General: Dry type transformers shall be factory assembled, metal enclosed, provided complete with mounting brackets as required. 1.03 SUBMITTALS A. Shop Drawings: Shop drawings shall be submitted showing dimensions, wiring diagrams, taps and nameplate nomenclature. B. Product Data: Product data shall be submitted showing compliance with this section of the specification, manufacturer's written recommendation for storage and protection, and installation instructions. 1.04 PRODUCT STORAGE AND HANDLING A. Protection: Physically protect transformers against damage as recommended by manufacturer. B. Storage: A waterproof covering shall be kept around all transformers until they are ready to be energized. 1.05 PAD MOUNTED TRANSFORMER - LIQUID FILLED A. Description: A factory assembled pad mounted transformer suitable for installation outdoors shall be provided and installed complete with incoming and outgoing primary oil fused cut outs, lightning arresters and metering C.T.'s on the secondary spades. 1.06 SUBMITTALS A. General: Provide shop drawings and product data on transformer showing compliance with these specifications including: 1. Pad dimensions with openings required. 2. Complete dimensions and drawings on transformer. 3. Coolant properties. TRANSFORMERS 16460-1
4. Incoming compartment equipment 5. Accessories. PART 2 - PRODUCTS 2.01 CONSTRUCTION - DRY TYPE TRANSFORMERS A. Listing: Dry type transformers shall be U.L. listed and certified to meet NEMA ST-1 with convection cooling and ST20. B. Testing: Transformers shall be tested and rated for sound level in accordance with ASA-C89.1-1961. C. Insulation: Class H insulation shall be employed for transformers above 30 KVA with maximum temperature rise of 150 degrees C. over 40 degrees C. Class F insulation shall be employed for transformers up to and including 30 KVA with a maximum temperature rise of 115 degrees C. over 40 degrees C. D. Windings: Three phase units shall be wound delta-wye. Each three phase transformer shall have three separate sets of coils. No Scott T connections, open delta, or two coil arrangements shall be permitted. E. Taps: Voltages shall be compatible with the application. Taps shall be provided two at plus 2-1/2 percent increments and two minus 2-1/2 percent increments from rated voltage. F. BIL: Basic impulse level shall be 90 KV. G. Manufacturers: Square-D, G.E. or Westinghouse. 2.02 PAD MOUNTED TRANSFORMER A. Type: Transformer shall be 500 KVA, 3-phase, 4160V delta primary, 480/277V, 3-phase, 4 wire WYE, secondary and shall conform to NEMA publications Nos. TR1, ST20 and ST1, and to ANSI Standard Nos. C57 and C89.1. B. Conformance: Pad-mounted transformer for installation outdoors shall be the self-cooled, oil-immersed type conforming to ANSI C57.12.22. C. Characteristics: Transformer cooling oil shall have the following principal characteristics; TRANSFORMERS 16460-2
1. Physical Properties Specifications Viscosity 37.8C-Saybolt Seconds 62 max Viscosity 0 degrees C-Saybolt 320 max Seconds Specific Gravity, 15.5/15.5.865 -.905 Pour Point (C) -40 max Flash Point (C) 145 max Condition Clear Water Content, parts per million 30 max Interfacial tension 25C-dynes/cm 40 2. Chemical Properties Specifications Acidity (mg.koh/g) 0.02 max Free Chloride or Sulfate 10 P.P.M. 0.1 max Corrosive Sulfur/Copper 19hr. Non-corrosive 140C Total combined Sulfur Percent.15 max Bomb Sludge Value (ASTM) Type 1.030 -.055 Percent (Tentative) Type 2.015 -.040 Type 3.010 -.135 3. Electrical Properties Specifications Dielectric Strength kv 30 min. Power factor 60 cycle - 100 C.30 max Resistivity (ohm-cm) 100 C 30 x 10 12 D. Tests: Transformer shall be tested and test results shall be submitted to the UF PPD. The tests shall include Transformer Turns Ratio (TTR), polarity, no-load loss, load loss, winding resistance measurements, impedance, temperature, impulse strength on liquid-filled transformers, sound level and existing current and low-frequency dielectric strength. A certified copy of the temperature, impedance and sound level tests performed previously on a transformer which is a duplicate electrically shall be accepted in lieu of temperature, impedance and sound level tests. Test results shall be submitted for review prior to energizing the transformer. E. Construction: The transformer and associated terminal compartments shall be so designed and constructed as to be tamper-proof and weatherproof, suitable for mounting on a pad with all live parts completely enclosed in lockable compartments. There shall be no screws, bolts or other externally removable fastening devices. Transformer tank shall be of welded steel construction forming a sealed unit. TRANSFORMERS 16460-3
1. Full-height, air filled incoming and outgoing terminal compartments with hinged doors shall be located side-by-side, separated by a rigid steel barrier, with the incoming compartment on the left. The incoming compartment shall be accessible only after the door to the outgoing compartment has been opened. High voltage door shall be held closed by captive stainless-steel bolt. 2. To facilitate making connections and permit cable pulling, the doors and compartment hood shall be removable. Removable door sill on compartment shall be provided to permit rolling or skidding of unit into place over conduit stubs in foundation. 3. Four full-capacity 2-1/2 percent rated primary taps, two above and two below rated volts, shall be provided, externally operable by a gang-operated tap changer mechanism for de-energized operation only and accessible from the primary terminal compartment. 4. The transformer enclosure shall be completely degreased followed by a rust-inhibiting primer and a finish coat of olive green. The compartment shall have a hinged door with a fastening device which is accessible only through the low-voltage compartment, and to make possible the use of a single padlock. 5. Incoming line equipment shall be arranged for radial feed, dead front, as indicated. Equipment enclosed in the incoming compartment shall include the following: a. Integral fused load break switch: Three 200 ampere integrated load break bushings with parking stands for mounting accessories. (1)Internal, oil-immersed, 2 position on-off gang operated load break switch. (2)Cartridge air fuses shall be provided installation in transformer sized to protect transformer. b. Switch ratings: (For 75-500 KVA transformers) (1)200 amperes load break and make (2)200 amperes continuous (3)5,000 amperes symmetrical; 9,000 amperes asymmetrical make-and-latch (4)6,000 amperes symmetrical; 10,000 amperes asymmetrical make-and-latch (5)60 KV BIL (6)5 KV rating TRANSFORMERS 16460-4
c. Cable entrances shall all be from bottom. Entrance fittings shall be single conductor type for each of the 3 cable entrances. Each fitting shall include a wiping sleeve for termination of EPLC or PILC cable specified herein. F. Accessories: The transformer shall be equipped with the following accessories as standard equipment: 1. Lightning arresters 2. Mounting pad for terminators 3. Nameplate 4. Lifting lugs or hooks 5. Ground pad - ANSI standard 6. One-inch drain valve and sampler 7. One-inch filling plug 8. Nameplate 9. One-half inch pipe plug for liquid-level indication 10. Metering C.T.'s on secondary spades. G. Ground Rod: Provide a 30 foot 3/4 inch sectional, copperweld ground rod in primary compartment section and ground cable sheath, secondary neutral, counterpoise and transformer enclosure to rods. Spare fuses (one set minimum). H. Pad Transformer Concrete Pad: Pad transformer concrete pad shall be provided and installed under Division 16 and shall conform to Section 3A, "Concrete Construction" and to the transformer manufacturer's specification regarding size, configuration and construction. PART 3 - EXECUTION 3.01 INSTALLATION A. Mounting: Transformers shall be mounted where accessible. No units may be mounted behind partitions, above ceilings, etc. Each transformer shall be mounted on 3 inch concrete base extending 3 inches outside all sides. B. Noise Isolation: Flexible conduits shall be used to isolate noise. C. Grounding: 1. Grounding and bonding shall be per NEC. Provide #4/0 AWG conductor run in 1 inch conduit; loop conductor from transformer to transformer and ground at main service ground. 2. Provide ground to building steel and size ground per NEC 250.94. END OF SECTION 16460 TRANSFORMERS 16460-5