⚡ Transformer Sizing Calculator
Determine the correct kVA rating for your electrical load. Ensure safe and efficient power distribution.
💡 Expert Tips
Don't forget the Power Factor. If you are sizing a generator or transformer for motors, the Power Factor (PF) matters. kVA = kW / PF. If you only know the kW (horsepower) of your motor, assume a PF of 0.8 to be safe.
Standard Sizes. Transformers don't come in every size. Common single-phase sizes are 10, 15, 25, 37.5, 50, 75, 100 kVA. Common 3-phase sizes are 15, 30, 45, 75, 112.5, 150, 225 kVA. Always round up to the next standard size.
Primary vs Secondary. This calculator sizes the transformer based on the LOAD (Secondary side). Ensure your primary supply voltage matches the transformer's primary rating (e.g., 480V Primary -> 240V Secondary).
"I see undersized transformers all the time. The client adds 'just one more machine' and suddenly the voltage drops and breakers trip. Always add that 25% buffer. It's cheaper to buy a bigger transformer now than to replace a blown one later."