Transformer Turns Ratio Calculator
Calculate transformer turns ratio, secondary voltage, and current from primary and secondary winding parameters.
Turns Ratio (Np:Ns)
4.00
Turns Ratio (Np:Ns) vs Primary Voltage
Transformer Turns Ratio
The turns ratio determines the voltage transformation between primary and secondary windings.
Formulas
Turns Ratio = Vp / Vs = Np / Ns
Ip = VA / Vp and Is = VA / Vs
Current transforms inversely: higher voltage means lower current, preserving power (minus losses).
Power Loss = VA x (1 - Efficiency)
Typical transformer efficiencies range from 90% (small) to 99% (large utility).
Example Calculation
480 V to 120 V step-down, 5 kVA, 95% efficient.
- 01Turns ratio: 480 / 120 = 4.00:1
- 02Primary current: 5000 / 480 = 10.42 A
- 03Secondary current: 5000 / 120 = 41.67 A
- 04Power loss: 5000 x 0.05 = 250 W
- 05Output power: 5000 x 0.95 = 4,750 W
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