Enter your Transformer Type, Primary Voltage, Secondary Voltage, Load Current, and Power Factor into the Transformer Sizing Calculator to find the Required Transformer kVA — along with your Primary Current, Apparent Power, and Voltage Ratio so you can spec the right transformer without second-guessing the math.
Required Transformer kVA
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Primary Current
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Apparent Power
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Voltage Ratio
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kVA (kilovolt-amperes) is the apparent power rating of a transformer. It represents the maximum load the transformer can handle and is calculated by multiplying voltage and current.
For single-phase: kVA = (Volts × Amps) ÷ 1000. For three-phase: kVA = (Volts × Amps × 1.732) ÷ 1000. Always add a safety margin of 20-25% to the calculated value.
The transformer size depends on your load requirements. Calculate the total kVA of all connected loads, add a safety margin, and select the next standard transformer size available.
Transformers use electromagnetic induction through primary and secondary windings. The voltage ratio depends on the turns ratio between primary and secondary coils.
Single-phase transformers handle single-phase power systems, while three-phase transformers are more efficient for larger loads and industrial applications. Three-phase calculations include a factor of 1.732 (√3).
Power factor affects the actual power consumption vs. apparent power. A lower power factor means higher current for the same real power, requiring a larger transformer.
Yes, it's recommended to add 20-25% safety margin to account for load growth, power factor variations, and ensure the transformer doesn't operate at full capacity continuously.