Transformer kVA Calculator
Calculate transformer kVA rating for single phase and three phase systems. Determine transformer size based on load requirements, voltage, and current.
Step 1: Calculation Method
Understanding kVA
kVA (kilovolt-ampere) is the unit of apparent power in an electrical circuit. It represents the total power in a system including both real power (kW) and reactive power (kVAR). For transformers, kVA rating indicates the maximum load it can handle.
Step 2: Calculation Options
Transformer Formulas
Single Phase: kVA = (V × I) ÷ 1000
Three Phase: kVA = (√3 × V × I) ÷ 1000
From Load: kVA = kW ÷ Power Factor
With Safety: kVA = Calculated kVA × (1 + Safety%)
Transformer kVA Calculation Results
Required Transformer Size
Standard Transformer Sizes
| Standard kVA | Single Phase Max Current (240V) | Three Phase Max Current (480V) | Typical Application | Your Load % |
|---|
Transformer Calculation Formulas
Single Phase Transformer
Formula: kVA = (Voltage × Current) ÷ 1000
Example: Voltage = 240V, Current = 100A → kVA = (240 × 100) ÷ 1000 = 24 kVA
Three Phase Transformer
Formula: kVA = (√3 × Voltage × Current) ÷ 1000
Example: Voltage = 480V, Current = 50A → kVA = (1.732 × 480 × 50) ÷ 1000 = 41.57 kVA
From Load & Power Factor
Formula: kVA = kW ÷ Power Factor
Example: Load = 50 kW, Power Factor = 0.8 → kVA = 50 ÷ 0.8 = 62.5 kVA
With Safety Margin
Formula: kVA with safety = Calculated kVA × (1 + Safety Factor)
Example: Calculated kVA = 24, Safety Factor = 20% → kVA = 24 × 1.2 = 28.8 kVA
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