Transformer worksheet
kVA and Amps Calculator
Convert between apparent power and current; 45 kVA at 480 V 3-phase gives 54.1 A, while 15 kVA at 240 V 1-phase gives 62.5 A.
Convert kVA and Amps
Convert between apparent power and current for transformer, generator, UPS, and load schedule worksheets: 45 kVA at 480 V 3-phase gives 54.1 A, while 15 kVA at 240 V 1-phase gives 62.5 A.
Result
Amps
90.21 A
Result notes
Keep the entered values, assumptions, and result together when adding this calculation to job notes or submittal records. Final installation choices should align with the applicable code edition, equipment listing, manufacturer instructions, local amendments, and AHJ requirements.
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Related charts
kVA to Amps Chart
Use this kVA to amps chart: 45 kVA at 480V 3-phase = 54.1A; 15 kVA at 240V 1-phase = 62.5A.
Transformer Sizing Chart
Estimate transformer kVA from load current, voltage, and phase, then document primary and secondary current, impedance, inrush, ventilation, and protection notes.
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Compare single-phase, split-phase, and balanced three-phase calculation contexts before choosing a power or motor calculator.
Related guides
Transformer Sizing Guide | 1600 kW to 2500 kVA
Size transformers from kW/PF: 1600 kW at PF 0.90 with 25% growth needs 2223 kVA, so select 2500 kVA; compare 480V vs 208V.
Transformer Sizing Chart | 200 kW = 300 kVA
Use transformer sizing chart: 200 kW at PF 0.85 gives 235 kVA, select 300 kVA; 300 kVA at 480V gives 360.8A and 7,216A at 5%Z.
Formula and field context
Convert between apparent power and current; 45 kVA at 480 V 3-phase gives 54.1 A, while 15 kVA at 240 V 1-phase gives 62.5 A.
Formula context
kVA to Amps Chart
For transformer and distribution work, kVA-to-amps is a line-current screen. 45 kVA at 480 V 3-phase gives about 54.1 A, while 15 kVA at 240 V 1-phase gives 62.5 A. Single-phase current uses kVA x 1000 divided by voltage. Balanced three-phase current uses kVA x 1000 divided by 1.732 x line-to-line voltage. Use the calculator after the chart when the result will feed a transformer schedule, feeder review, load bank setup, or equipment submittal.
Formula
Single phase: A = kVA x 1000 / V. Three phase: A = kVA x 1000 / (1.732 x VLL).Variables to keep with the result
- A is line current in amperes.
- kVA is apparent power from the transformer, UPS, generator, or load schedule.
- V is circuit voltage for single-phase work.
- VLL is line-to-line voltage for balanced three-phase systems.
Formula and voltage basis
For single-phase apparent power, amps equals kVA times 1,000 divided by volts. For balanced three-phase equipment, amps equals kVA times 1,000 divided by the square root of 3 and line-to-line volts. This is why a 75 kVA transformer has a different full-load current at 208 V than it does at 480 V.
Where electricians use it
This conversion is common when reviewing transformer secondary current, generator load, UPS output, and commercial load schedules. It supports field documentation before opening a full transformer or generator calculator, especially when the nameplate is written in kVA instead of kW.
Limits and escalation
The result is an apparent-power current, not a short-circuit study, conductor selection, or overcurrent-device setting. Use the transformer calculator for full-load current and voltage relationship review, and use the transformer impedance or short-circuit calculator when available fault current matters.