Transformer Excitation Current
Updated 2026-10-24
| Relationship | Entry |
|---|---|
| Governing standard | IEEE C57.12.90-2021 (IEEE Standard Test Code for Liquid-Immersed Distribution, Power, and Regulating Transformers) |
Data records
- Transformer Excitation Current is specified for load tap changers in acceptance testing at clause 7.12.3.B.12 of ANSI/NETA ATS-2025. Value: load tap changers.
- Transformer Excitation Current is specified for load tap changers in maintenance testing at clause 7.12.3.B.12 of ANSI/NETA MTS-2023. Value: load tap changers.
- Transformer Excitation Current is specified for liquid-filled transformers in acceptance testing at clause 7.2.2.B.6 of ANSI/NETA ATS-2025. Value: liquid-filled transformers.
- Transformer Excitation Current is specified for liquid-filled transformers in maintenance testing at clause 7.2.2.B.6 of ANSI/NETA MTS-2023. Value: liquid-filled transformers.
- Transformer Excitation Current is specified for large air-cooled dry-type transformers in acceptance testing at clause 7.2.1.2.B.6 of ANSI/NETA ATS-2025. Value: large air-cooled dry-type transformers.
- Transformer Excitation Current is specified for large air-cooled dry-type transformers in maintenance testing at clause 7.2.1.2.B.6 of ANSI/NETA MTS-2023. Value: large air-cooled dry-type transformers.
- Transformer Excitation Current is addressed in ANSI/NETA ATS-2025.
- Transformer Excitation Current is addressed in ANSI/NETA MTS-2023.
- Clause 8.5 of IEEE C57.12.90-2021 states excitation current relative to the energized winding's rated line current, uses the smallest kVA rating as the base on a unit that carries more than one cooling-class rating, and for a three-phase unit averages the magnitudes of the line currents recorded during the no-load loss test.
- In IEEE C57.12.90-2021 excitation current is a factory quantity measured at rated voltage on a sine-wave basis during the no-load loss test of clause 8, with the test voltage set by the average-voltage voltmeter method of clause 8.2; the code gives no field procedure for excitation current.
- The test method is named Transformer Excitation Current. Value: Transformer Excitation Current.
Elsewhere in the family
- CT Excitation and Saturation related entry on Revenue Metering Reference
- Current Circuit Injection related entry on Electrical Testing Reference
- Current circuit injection related entry on Switchgear Testing Reference
- ANSI/NETA ATS-2025 Standard for Acceptance Testing Specifications related entry on Electrical Testing Reference
- ANSI/NETA MTS-2023 Standard for Maintenance Testing Specifications related entry on Electrical Testing Reference
Sources
- ANSI/NETA ATS-2025, Acceptance Testing Specifications for Electrical Power Equipment and Systems, 2025 edition, NETA. Cited: clause 7.12.3.B.12; clause 7.2.2.B.6; clause 7.2.1.2.B.6. Held as: Purchased single-user copy. Publisher page
- ANSI/NETA MTS-2023, Maintenance Testing Specifications for Electrical Power Equipment and Systems, 2023 edition, NETA. Cited: clause 7.12.3.B.12; clause 7.2.2.B.6; clause 7.2.1.2.B.6. Held as: Purchased single-user copy. Publisher page
- Electrical Testing Reference editorial taxonomy, Electrical Testing Reference editorial taxonomy of test methods, 2026-10 edition, Electrical Testing Reference. Held as: Own observation.
- IEEE C57.12.90-2021, Test Code for Liquid-Immersed Distribution, Power and Regulating Transformers, 2021 edition, IEEE. Cited: clause 8.5; clause 8.1, 8.2. Held as: Purchased single-user copy.
Obtaining the documents
- ANSI/NETA ATS-2025: publisher catalog or sales page
- ANSI/NETA MTS-2023: publisher catalog or sales page
- IEEE C57.12.90-2021: publisher catalog or sales page
Changelog (14 entries)
| Date | Revision | Change |
|---|---|---|
| 2026-10-24 | created (tests.transformer-excitation-current.ieeec57-12-90.basis) | |
| 2026-10-24 | revised (tests.transformer-excitation-current.ieeec57-12-90.basis) | |
| 2026-10-24 | review_status unreviewed -> software_reviewed (tests.transformer-excitation-current.ieeec57-12-90.basis) | |
| 2026-10-24 | created (tests.transformer-excitation-current.ieeec57-12-90.factory-basis) | |
| 2026-10-24 | review_status unreviewed -> software_reviewed (tests.transformer-excitation-current.ieeec57-12-90.factory-basis) | |
| 2026-10-13 | created (tests.transformer-excitation-current.equipment.regulator.acceptance) | |
| 2026-10-13 | created (tests.transformer-excitation-current.equipment.regulator.maintenance) | |
| 2026-10-13 | created (tests.transformer-excitation-current.equipment.transformer-fluid.acceptance) | |
| 2026-10-13 | created (tests.transformer-excitation-current.equipment.transformer-fluid.maintenance) | |
| 2026-10-13 | created (tests.transformer-excitation-current.equipment.transformer.acceptance) | |
| 2026-10-13 | created (tests.transformer-excitation-current.equipment.transformer.maintenance) | |
| 2026-10-13 | created (tests.transformer-excitation-current.governed-by.ansi-neta-ats) | |
| 2026-10-13 | created (tests.transformer-excitation-current.governed-by.ansi-neta-mts) | |
| 2026-10-13 | created (tests.transformer-excitation-current.title) |
Cite this page
Cite the governing standard for the fact itself; cite this page as the finding aid.
"Transformer Excitation Current." Transformer Testing Reference. 2026-10-24. https://www.transformertestingreference.com/tests/transformer-excitation-current/.
Transformer Testing Reference, Transformer Excitation Current (Oct. 24, 2026), https://www.transformertestingreference.com/tests/transformer-excitation-current/.
@misc{etr-tests-transformer-excitation-current,
title = {Transformer Excitation Current},
howpublished = {\url{https://www.transformertestingreference.com/tests/transformer-excitation-current/}},
organization = {Transformer Testing Reference},
publisher = {Transformer Testing Reference},
year = {2026},
note = {last substantive change 2026-10-24}
}{{cite web |title=Transformer Excitation Current |website=Transformer Testing Reference |publisher=Transformer Testing Reference |url=https://www.transformertestingreference.com/tests/transformer-excitation-current/ |date=2026-10-24 |access-date=}}