Exhibit_G_Section_26_22_13_-_Low-Voltage_Distribution_Transformers_(1).pdf
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- Solicitation number
- 59-26
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- Pinellas County, Clewiston City, Florida
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This document is a technical specification (Section 262213) for low-voltage distribution transformers, which serves as an exhibit to a design-build contract for standby generator services at Clearwater Executive Airport's CNG station in Florida. The specification establishes requirements for factory-assembled, air-cooled, dry-type distribution transformers with nominal primary and secondary ratings of 600 volts or less and capacities up to 1500 kVA for 60 Hz service. Acceptable manufacturers include ABB Electrification Installations Products, Eaton, Powersmiths International Corp., Prolec GE, Siemens Industry Inc., SolaHD, and Square D/Schneider Electric USA. The specification mandates detailed product data submissions including construction details, dimensions, performance specifications, and shop drawings with vibration isolation base details and wiring diagrams. Transformers rated 15 kVA and larger must comply with DOE 2016 efficiency levels per 10 CFR 431 and be marked accordingly. All transformers must comply with NFPA 70 and be listed to UL 1561 standards.
The specification requires comprehensive factory testing and field quality control measures, including resistance measurements, ratio tests, insulation-resistance tests, and temperature testing conducted by qualified electrical testing laboratories. Field testing must be witnessed by the owner's representative and includes visual and mechanical inspections, electrical tests specific to transformer size, and infrared scanning of transformer connections at two months, four months, and eleven months after substantial completion. Installation requirements mandate level and plumb placement on concrete bases with vibration-dampening supports, flexible connections at terminations to eliminate vibration transmission, and proper torque application per manufacturer specifications. The specification requires temporary heating during storage, removal of all shipping restraints before energization, and infrared scanning with certified reporting of any deficiencies and remedial actions taken.
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LOW-VOLTAGE DISTRIBUTION
TRANSFORMERS
262213 - 1
Copyright © 2024 by the American Institute of Architects. Warning: This AIA MasterSpec based document is protected by U.S.
Copyright Law and International Treaties. A valid, current MasterSpec license is required for editing or use of this document.
SECTION 262213 - LOW-VOLTAGE DISTRIBUTION TRANSFORMERS
PART 1 - GENERAL
1.1 SUMMARY
A. Section Includes:
1. Distribution, dry-type transformers with nominal primary and secondary rating of 600 V and less, with capacities up to 1500 kVA.
1.2 ACTION SUBMITTALS
A. Product Data:
1. For each type of product.
a. Include construction details, material descriptions, dimensions of individual components and profiles, and finishes for each type and size of transformer.
b. Include rated nameplate data, capacities, weights, dimensions, minimum clearances, installed devices and features, and performance for each type and size of transformer.
B. Shop Drawings:
1. Detail equipment assemblies and indicate dimensions, weights, loads, required clearances, method of field assembly, components, and location and size of field connections.
2. Vibration Isolation Base Details: Detail fabrication including anchorages and attachments to structure and to supported equipment.
3. Include diagrams for power, signal, and control wiring.
C. Field Quality-Control Submittals:
1. Field quality-control reports.
1.3 INFORMATIONAL SUBMITTALS
A. Manufacturers' Published Instructions: Record copy of official installation and testing instructions issued to Installer by manufacturer for the following:
1. Transformer temporary heating, working clearances, anchoring, torque values, and insulation-resistance testing.
B. Source quality-control reports.
262213 - 2
Copyright © 2024 by the American Institute of Architects. Warning: This AIA MasterSpec based document is protected by U.S.
Copyright Law and International Treaties. A valid, current MasterSpec license is required for editing or use of this document.
1.4 DELIVERY, STORAGE, AND HANDLING
A. Inspection: On receipt, inspect for and note shipping damage to packaging and transformer.
1. If manufacturer packaging is removed for inspection, and transformer will be stored after inspection, re-package transformer using original or new packaging materials that provide protection equivalent to manufacturer's packaging.
B. Storage: Store in warm, dry, and temperature-stable location in original shipping packaging.
C. Temporary Heating: Apply temporary heat in accordance with manufacturer's published instructions within enclosure of ventilated-type units, throughout periods during which equipment is not energized and when transformer is not in space that is continuously under normal control of temperature and humidity.
D. Handling: Follow manufacturer's instructions for lifting and transporting transformers.
PART 2 - PRODUCTS
2.1 LOW-VOLTAGE DISTRIBUTION TRANSFORMERS
A. Manufacturers: Subject to compliance with requirements, provide products by one of the following:
1. ABB Electrification Installations Products
2. Eaton
3. Powersmiths International Corp.; Socomec Group
4. Prolec GE; A Xignux and General Electric Company Joint Venture
5. Siemens Industry, Inc., Energy Management Division
6. SolaHD; Emerson Electric Co., Automation Solutions
7. Square D; Schneider Electric USA
B. Source Limitations: Obtain each type of transformer from single source from single manufacturer.
2.2 GENERAL TRANSFORMER REQUIREMENTS
A. Description: Factory-assembled and -tested, air-cooled units for 60 Hz service.
B. Electrical Components, Devices, and Accessories: Listed and labeled in accordance with NFPA 70, by qualified electrical testing laboratory recognized by authorities having jurisdiction, and marked for intended location and application.
C. Transformers Rated 15 kVA and Larger:
1. Comply with 10 CFR 431 (DOE 2016) efficiency levels.
2. Marked as compliant with DOE 2016 efficiency levels by qualified electrical
262213 - 3
Copyright © 2024 by the American Institute of Architects. Warning: This AIA MasterSpec based document is protected by U.S.
Copyright Law and International Treaties. A valid, current MasterSpec license is required for editing or use of this document.
testing laboratory recognized by authorities having jurisdiction.
D. Shipping Restraints: Paint or otherwise color-code bolts, wedges, blocks, and other restraints that are to be removed after installation and before energizing. Use fluorescent colors that are easily identifiable inside transformer enclosure.
2.3 DISTRIBUTION TRANSFORMERS
A. Comply with NFPA 70, and list and label as complying with UL 1561.
B. Cores: Electrical grade, non-aging silicon steel with high permeability and low hysteresis losses.
1. One leg per phase.
2. Core volume must allow efficient transformer operation at 10 percent above nominal tap voltage.
3. Grounded to enclosure.
C. Coils: Continuous windings without splices except for taps.
1. Coil Material: Copper.
2. Internal Coil Connections: Brazed or pressure type.
3. Terminal Connections: Welded.
D. Enclosure: Ventilated.
1. Core and coil must be encapsulated within resin compound using vacuum-pressure impregnation process to seal out moisture and air.
2. KVA Ratings: Based on convection cooling only and not relying on auxiliary fans.
3. Wiring Compartment: Sized for conduit entry and wiring installation.
4. Environmental Protection:
a. Indoor: UL 50E, Type 2.
5. Finish Color: Gray, weather-resistant enamel.
E. Taps for Transformers 25 kVA and Larger: Two 2.5 percent taps above and two 2.5 percent taps below normal full capacity.
F. Insulation Class, 30 kVA and Larger: 220 deg C, UL-component-recognized insulation system with maximum of 80 deg C rise above 40 deg C ambient temperature.
G. Grounding: Provide ground-bar kit or ground bar installed on inside of transformer enclosure.
H. Low-Sound-Level Requirements: Maximum sound levels when factory tested in accordance with IEEE C57.12.91.
262213 - 4
Copyright © 2024 by the American Institute of Architects. Warning: This AIA MasterSpec based document is protected by U.S.
Copyright Law and International Treaties. A valid, current MasterSpec license is required for editing or use of this document.
2.4 IDENTIFICATION
A. Nameplates:
1. Engraved, laminated-acrylic or melamine plastic signs for distribution transformers, mounted with corrosion-resistant screws.
2.5 SOURCE QUALITY CONTROL
A. Testing Administrant: Engage qualified electrical testing agency to evaluate transformer.
B. Factory Tests and Inspections: Test and inspect assembled system, by, or under supervision of, qualified electrical testing laboratory recognized by authorities having jurisdiction, in accordance with IEEE C57.12.01 and IEEE C57.12.91 before delivering to site. Affix label with name and date of manufacturer's certification of system compliance on control units.
1. Resistance measurements of windings at rated voltage connections and at tap connections.
2. Ratio tests at rated voltage connections and at tap connections.
3. Phase relation and polarity tests at rated voltage connections.
4. No load losses, and excitation current and rated voltage at rated voltage connections.
5. Impedance and load losses at rated current and rated frequency at rated voltage connections.
6. Applied and induced tensile tests.
7. Regulation and efficiency at rated load and voltage.
8. Insulation-Resistance Tests:
a. Line-side to ground.
b. Load-side to ground.
c. Line-side to load-side.
9. Temperature tests.
10. Factory Sound-Level Tests: Conduct prototype sound-level tests on production-line products.
C. Nonconforming Work:
1. System equipment that does not pass tests and inspections will be considered defective.
D. Prepare test and inspection reports.
262213 - 5
Copyright © 2024 by the American Institute of Architects. Warning: This AIA MasterSpec based document is protected by U.S.
Copyright Law and International Treaties. A valid, current MasterSpec license is required for editing or use of this document.
PART 3 - EXECUTION
3.1 EXAMINATION
A. Examine conditions for compliance with enclosure- and ambient-temperature requirements for transformers.
B. Verify that field measurements are as needed to maintain working clearances required by NFPA 70 and manufacturer's published instructions.
C. Examine walls, floors, roofs, and concrete bases for suitable mounting conditions where transformers will be installed.
D. Verify that ground connections are in place and requirements in Section 260526 "Grounding and Bonding for Electrical Systems" have been met. Maximum ground resistance must be 5 Ω at location of transformer.
E. Environment: Enclosures must be rated for environment in which they are located.
Covers for UL 50E, Type 4X enclosures may not cause accessibility problems.
F. Proceed with installation only after unsatisfactory conditions have been corrected.
3.2 INSTALLATION
A. Install transformers level and plumb on concrete base with vibration-dampening supports. Locate transformers away from corners and not parallel to adjacent wall surface.
B. Construct concrete bases and anchor floor-mounted transformers in accordance with manufacturer's published instructions.
1. Coordinate size and location of concrete bases with actual transformer provided.
Cast anchor-bolt inserts into bases. Concrete, reinforcement, and formwork requirements are specified with concrete.
C. Secure transformer to concrete base in accordance with manufacturer's published instructions.
D. Secure covers to enclosure and tighten bolts to manufacturer-recommended torques to reduce noise generation.
E. Remove shipping bolts, blocking, and wedges.
3.3 CONNECTIONS
A. Tighten electrical connectors and terminals in accordance with manufacturer's published torque-tightening values. If manufacturer's torque values are not indicated, use those specified in UL 486A-486B.
262213 - 6
Copyright © 2024 by the American Institute of Architects. Warning: This AIA MasterSpec based document is protected by U.S.
Copyright Law and International Treaties. A valid, current MasterSpec license is required for editing or use of this document.
B. Provide flexible connections at conduit and conductor terminations and supports to eliminate sound and vibration transmission to building structure.
3.4 FIELD QUALITY CONTROL
A. Field tests and inspections must be witnessed by Owner’s representative.
B. Tests and Inspections:
1. Small (Up to 167 kVA Single-Phase or 500 kVA Three-Phase) Dry-Type Transformer Field Tests:
a. Visual and Mechanical Inspection.
1) Inspect physical and mechanical condition.
2) Inspect anchorage, alignment, and grounding.
3) Verify that resilient mounts are free and that shipping brackets have been removed.
4) Verify that unit is clean.
5) Perform specific inspections and mechanical tests recommended by manufacturer.
6) Verify that as-left tap connections are as specified.
7) Verify presence of surge arresters and that their ratings are as specified.
b. Electrical Tests:
1) Measure resistance at windings, taps, and bolted connections.
2) Perform insulation-resistance tests winding-to-winding and windings-to-ground. Apply voltage in accordance with manufacturer's published data. In absence of manufacturer's published data, comply with NETA ATS, Table 100.5. Calculate polarization index: value of index may not be less than 1.0.
3) Perform turns-ratio tests at tap positions. Test results may not deviate by more than one-half percent from either adjacent coils or calculated ratio. If test fails, replace transformer.
4) Verify correct secondary voltage, phase-to-phase and phase-to-neutral, after energization and prior to loading.
2. Large (Larger Than 167 kVA Single Phase or 500 kVA Three Phase) Dry-Type Transformer Field Tests:
a. Visual and Mechanical Inspection:
1) Inspect physical and mechanical condition.
2) Inspect anchorage, alignment, and grounding.
3) Verify that resilient mounts are free and that shipping brackets have been removed.
4) Verify that unit is clean.
5) Perform specific inspections and mechanical tests recommended by
262213 - 7
Copyright © 2024 by the American Institute of Architects. Warning: This AIA MasterSpec based document is protected by U.S.
Copyright Law and International Treaties. A valid, current MasterSpec license is required for editing or use of this document.
manufacturer.
6) Verify that as-left tap connections are as specified.
7) Verify presence of surge arresters and that their ratings are as specified.
b. Electrical Tests:
1) Measure resistance at windings, taps, and bolted connections.
2) Perform insulation-resistance tests winding-to-winding and windings-to-ground. Apply voltage in accordance with manufacturer's published data. In absence of manufacturer's published data, comply with NETA ATS, Table 100.5. Calculate polarization index: value of index may not be less than 1.0.
3) Perform power-factor or dissipation-factor tests on windings.
4) Perform turns-ratio tests at tap positions. Test results may not deviate by more than one-half percent from either adjacent coils or calculated ratio. If test fails, replace transformer.
5) Perform excitation-current test on each phase.
6) Perform applied voltage test on line- and load-side windings to ground. See IEEE C57.12.91, Sections 10.2 and 10.9.
7) Verify correct secondary voltage, phase-to-phase and phase-to-neutral, after energization and prior to loading.
C. Test Labeling: On completion of satisfactory testing of units, attach dated and signed "Satisfactory Test" label to tested components.
D. Nonconforming Work:
1. Transformer will be considered defective if it does not pass tests and inspections.
2. Remove and replace units that do not pass tests or inspections and retest as specified above.
E. Assemble and submit test and inspection reports.
F. Manufacturer Services:
1. Engage factory-authorized service representative to supervise field tests and inspections.
3.5 ADJUSTING
A. Record transformer secondary voltage at unit for at least 48 hours of typical occupancy period. Adjust transformer taps to provide optimum voltage conditions at secondary terminals. Optimum is defined as not exceeding nameplate voltage plus 5 percent and not being lower than nameplate voltage minus 3 percent at maximum load conditions.
Submit recording and tap settings as test results.
B. Output Settings Report: Prepare written report recording output voltages and tap settings.
262213 - 8
Copyright © 2024 by the American Institute of Architects. Warning: This AIA MasterSpec based document is protected by U.S.
Copyright Law and International Treaties. A valid, current MasterSpec license is required for editing or use of this document.
3.6 CLEANING
A. Vacuum dirt and debris; do not use compressed air to assist in cleaning.
3.7 MAINTENANCE
A. Infrared Scanning: Two months after Substantial Completion, perform infrared scan of transformer connections.
1. Use infrared-scanning device designed to measure temperature or detect significant deviations from normal values. Provide documentation of device calibration.
2. Perform two follow-up infrared scans of transformers, one at four months and another at 11 months after Substantial Completion.
3. Prepare certified report identifying transformer checked and describing results of scanning. Include notation of deficiencies detected, remedial actions taken, and scanning observations after remedial action.
END OF SECTION 262213
| SECTION 262213 - LOW-VOLTAGE DISTRIBUTION TRANSFORMERS |
| PART 1 - GENERAL |
| 1.1 SUMMARY |
| A. Section Includes: |
| 1. Distribution, dry-type transformers with nominal primary and secondary rating of 600 V and less, with capacities up to 1500 kVA. |
| 1.2 ACTION SUBMITTALS |
| A. Product Data: |
| 1. For each type of product. |
| a. Include construction details, material descriptions, dimensions of individual components and profiles, and finishes for each type and size of transformer. |
| b. Include rated nameplate data, capacities, weights, dimensions, minimum clearances, installed devices and features, and performance for each type and size of transformer. |
| B. Shop Drawings: |
| 1. Detail equipment assemblies and indicate dimensions, weights, loads, required clearances, method of field assembly, components, and location and size of field connections. |
| 2. Vibration Isolation Base Details: Detail fabrication including anchorages and attachments to structure and to supported equipment. |
| 3. Include diagrams for power, signal, and control wiring. |
| C. Field Quality-Control Submittals: |
| 1. Field quality-control reports. |
| 1.3 INFORMATIONAL SUBMITTALS |
| A. Manufacturers' Published Instructions: Record copy of official installation and testing instructions issued to Installer by manufacturer for the following: |
| 1. Transformer temporary heating, working clearances, anchoring, torque values, and insulation-resistance testing. |
B. Source quality-control reports.
| 1.4 DELIVERY, STORAGE, AND HANDLING |
| A. Inspection: On receipt, inspect for and note shipping damage to packaging and transformer. |
| 1. If manufacturer packaging is removed for inspection, and transformer will be stored after inspection, re-package transformer using original or new packaging materials that provide protection equivalent to manufacturer's packaging. |
| B. Storage: Store in warm, dry, and temperature-stable location in original shipping packaging. |
| C. Temporary Heating: Apply temporary heat in accordance with manufacturer's published instructions within enclosure of ventilated-type units, throughout periods during which equipment is not energized and when transformer is not in space that is cont... |
| D. Handling: Follow manufacturer's instructions for lifting and transporting transformers. |
| PART 2 - PRODUCTS |
| 2.1 LOW-VOLTAGE DISTRIBUTION TRANSFORMERS |
| A. Manufacturers: Subject to compliance with requirements, provide products by one of the following: |
| 1. ABB Electrification Installations Products |
| 2. Eaton |
| 3. Powersmiths International Corp.; Socomec Group |
| 4. Prolec GE; A Xignux and General Electric Company Joint Venture |
| 5. Siemens Industry, Inc., Energy Management Division |
| 6. SolaHD; Emerson Electric Co., Automation Solutions |
| 7. Square D; Schneider Electric USA |
B. Source Limitations: Obtain each type of transformer from single source from single manufacturer.
| 2.2 GENERAL TRANSFORMER REQUIREMENTS |
| A. Description: Factory-assembled and -tested, air-cooled units for 60 Hz service. |
| B. Electrical Components, Devices, and Accessories: Listed and labeled in accordance with NFPA 70, by qualified electrical testing laboratory recognized by authorities having jurisdiction, and marked for intended location and application. |
| C. Transformers Rated 15 kVA and Larger: |
| 1. Comply with 10 CFR 431 (DOE 2016) efficiency levels. |
| 2. Marked as compliant with DOE 2016 efficiency levels by qualified electrical testing laboratory recognized by authorities having jurisdiction. |
D. Shipping Restraints: Paint or otherwise color-code bolts, wedges, blocks, and other restraints that are to be removed after installation and before energizing. Use fluorescent colors that are easily identifiable inside transformer enclosure.
| 2.3 DISTRIBUTION TRANSFORMERS |
| A. Comply with NFPA 70, and list and label as complying with UL 1561. |
| B. Cores: Electrical grade, non-aging silicon steel with high permeability and low hysteresis losses. |
| 1. One leg per phase. |
| 2. Core volume must allow efficient transformer operation at 10 percent above nominal tap voltage. |
| 3. Grounded to enclosure. |
| C. Coils: Continuous windings without splices except for taps. |
| 1. Coil Material: Copper. |
| 2. Internal Coil Connections: Brazed or pressure type. |
| 3. Terminal Connections: Welded. |
| D. Enclosure: Ventilated. |
| 1. Core and coil must be encapsulated within resin compound using vacuum-pressure impregnation process to seal out moisture and air. |
| 2. KVA Ratings: Based on convection cooling only and not relying on auxiliary fans. |
| 3. Wiring Compartment: Sized for conduit entry and wiring installation. |
| 4. Environmental Protection: |
| a. Indoor: UL 50E, Type 2. |
5. Finish Color: Gray, weather-resistant enamel.
| E. Taps for Transformers 25 kVA and Larger: Two 2.5 percent taps above and two 2.5 percent taps below normal full capacity. |
| F. Insulation Class, 30 kVA and Larger: 220 deg C, UL-component-recognized insulation system with maximum of 80 deg C rise above 40 deg C ambient temperature. |
| G. Grounding: Provide ground-bar kit or ground bar installed on inside of transformer enclosure. |
| H. Low-Sound-Level Requirements: Maximum sound levels when factory tested in accordance with IEEE C57.12.91. |
| 2.4 IDENTIFICATION |
| A. Nameplates: |
| 1. Engraved, laminated-acrylic or melamine plastic signs for distribution transformers, mounted with corrosion-resistant screws. |
| 2.5 SOURCE QUALITY CONTROL |
| A. Testing Administrant: Engage qualified electrical testing agency to evaluate transformer. |
| B. Factory Tests and Inspections: Test and inspect assembled system, by, or under supervision of, qualified electrical testing laboratory recognized by authorities having jurisdiction, in accordance with IEEE C57.12.01 and IEEE C57.12.91 before delive... |
| 1. Resistance measurements of windings at rated voltage connections and at tap connections. |
| 2. Ratio tests at rated voltage connections and at tap connections. |
| 3. Phase relation and polarity tests at rated voltage connections. |
| 4. No load losses, and excitation current and rated voltage at rated voltage connections. |
| 5. Impedance and load losses at rated current and rated frequency at rated voltage connections. |
| 6. Applied and induced tensile tests. |
| 7. Regulation and efficiency at rated load and voltage. |
| 8. Insulation-Resistance Tests: |
| a. Line-side to ground. |
| b. Load-side to ground. |
| c. Line-side to load-side. |
| 9. Temperature tests. |
| 10. Factory Sound-Level Tests: Conduct prototype sound-level tests on production-line products. |
| C. Nonconforming Work: |
| 1. System equipment that does not pass tests and inspections will be considered defective. |
D. Prepare test and inspection reports.
| PART 3 - EXECUTION |
| 3.1 EXAMINATION |
| A. Examine conditions for compliance with enclosure- and ambient-temperature requirements for transformers. |
| B. Verify that field measurements are as needed to maintain working clearances required by NFPA 70 and manufacturer's published instructions. |
| C. Examine walls, floors, roofs, and concrete bases for suitable mounting conditions where transformers will be installed. |
| D. Verify that ground connections are in place and requirements in Section 260526 "Grounding and Bonding for Electrical Systems" have been met. Maximum ground resistance must be 5 Ω at location of transformer. |
| E. Environment: Enclosures must be rated for environment in which they are located. Covers for UL 50E, Type 4X enclosures may not cause accessibility problems. |
| F. Proceed with installation only after unsatisfactory conditions have been corrected. |
| 3.2 INSTALLATION |
| A. Install transformers level and plumb on concrete base with vibration-dampening supports. Locate transformers away from corners and not parallel to adjacent wall surface. |
| B. Construct concrete bases and anchor floor-mounted transformers in accordance with manufacturer's published instructions. |
| 1. Coordinate size and location of concrete bases with actual transformer provided. Cast anchor-bolt inserts into bases. Concrete, reinforcement, and formwork requirements are specified with concrete. |
| C. Secure transformer to concrete base in accordance with manufacturer's published instructions. |
| D. Secure covers to enclosure and tighten bolts to manufacturer-recommended torques to reduce noise generation. |
| E. Remove shipping bolts, blocking, and wedges. |
| 3.3 CONNECTIONS |
| A. Tighten electrical connectors and terminals in accordance with manufacturer's published torque-tightening values. If manufacturer's torque values are not indicated, use those specified in UL 486A-486B. |
| B. Provide flexible connections at conduit and conductor terminations and supports to eliminate sound and vibration transmission to building structure. |
| 3.4 FIELD QUALITY CONTROL |
| A. Field tests and inspections must be witnessed by Owner’s representative. |
| B. Tests and Inspections: |
| 1. Small (Up to 167 kVA Single-Phase or 500 kVA Three-Phase) Dry-Type Transformer Field Tests: |
| a. Visual and Mechanical Inspection. |
| 1) Inspect physical and mechanical condition. |
| 2) Inspect anchorage, alignment, and grounding. |
| 3) Verify that resilient mounts are free and that shipping brackets have been removed. |
| 4) Verify that unit is clean. |
| 5) Perform specific inspections and mechanical tests recommended by manufacturer. |
| 6) Verify that as-left tap connections are as specified. |
| 7) Verify presence of surge arresters and that their ratings are as specified. |
| b. Electrical Tests: |
| 1) Measure resistance at windings, taps, and bolted connections. |
| 2) Perform insulation-resistance tests winding-to-winding and windings-to-ground. Apply voltage in accordance with manufacturer's published data. In absence of manufacturer's published data, comply with NETA ATS, Table 100.5. Calculate polarization in... |
| 3) Perform turns-ratio tests at tap positions. Test results may not deviate by more than one-half percent from either adjacent coils or calculated ratio. If test fails, replace transformer. |
| 4) Verify correct secondary voltage, phase-to-phase and phase-to-neutral, after energization and prior to loading. |
| 2. Large (Larger Than 167 kVA Single Phase or 500 kVA Three Phase) Dry-Type Transformer Field Tests: |
| a. Visual and Mechanical Inspection: |
| 1) Inspect physical and mechanical condition. |
| 2) Inspect anchorage, alignment, and grounding. |
| 3) Verify that resilient mounts are free and that shipping brackets have been removed. |
| 4) Verify that unit is clean. |
| 5) Perform specific inspections and mechanical tests recommended by manufacturer. |
| 6) Verify that as-left tap connections are as specified. |
| 7) Verify presence of surge arresters and that their ratings are as specified. |
| b. Electrical Tests: |
| 1) Measure resistance at windings, taps, and bolted connections. |
| 2) Perform insulation-resistance tests winding-to-winding and windings-to-ground. Apply voltage in accordance with manufacturer's published data. In absence of manufacturer's published data, comply with NETA ATS, Table 100.5. Calculate polarization in... |
| 3) Perform power-factor or dissipation-factor tests on windings. |
| 4) Perform turns-ratio tests at tap positions. Test results may not deviate by more than one-half percent from either adjacent coils or calculated ratio. If test fails, replace transformer. |
| 5) Perform excitation-current test on each phase. |
| 6) Perform applied voltage test on line- and load-side windings to ground. See IEEE C57.12.91, Sections 10.2 and 10.9. |
| 7) Verify correct secondary voltage, phase-to-phase and phase-to-neutral, after energization and prior to loading. |
| C. Test Labeling: On completion of satisfactory testing of units, attach dated and signed "Satisfactory Test" label to tested components. |
| D. Nonconforming Work: |
| 1. Transformer will be considered defective if it does not pass tests and inspections. |
| 2. Remove and replace units that do not pass tests or inspections and retest as specified above. |
| E. Assemble and submit test and inspection reports. |
| F. Manufacturer Services: |
| 1. Engage factory-authorized service representative to supervise field tests and inspections. |
| 3.5 ADJUSTING |
| A. Record transformer secondary voltage at unit for at least 48 hours of typical occupancy period. Adjust transformer taps to provide optimum voltage conditions at secondary terminals. Optimum is defined as not exceeding nameplate voltage plus 5 perce... |
| B. Output Settings Report: Prepare written report recording output voltages and tap settings. |
| 3.6 CLEANING |
| A. Vacuum dirt and debris; do not use compressed air to assist in cleaning. |
| 3.7 MAINTENANCE |
| A. Infrared Scanning: Two months after Substantial Completion, perform infrared scan of transformer connections. |
| 1. Use infrared-scanning device designed to measure temperature or detect significant deviations from normal values. Provide documentation of device calibration. |
| 2. Perform two follow-up infrared scans of transformers, one at four months and another at 11 months after Substantial Completion. |
| 3. Prepare certified report identifying transformer checked and describing results of scanning. Include notation of deficiencies detected, remedial actions taken, and scanning observations after remedial action. |
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