Enter any two values and the third will be calculated.
Rex Power Magnetics makes no representations as to the accuracy of the information used by or generated by this calculator. The results are provided for general reference only and should be independently verified by a qualified professional before being relied upon. Rex Power Magnetics assumes no responsibility for the results generated by the calculator or for any errors or omissions in connection with its use, and under no circumstances shall Rex Power Magnetics be held liable for any damages arising from the use of, or results generated by, the calculator.
Enter the real power and power factor to calculate apparent power (kVA).
Rex Power Magnetics makes no representations as to the accuracy of the information used by or generated by this calculator. The results are provided for general reference only and should be independently verified by a qualified professional before being relied upon. Rex Power Magnetics assumes no responsibility for the results generated by the calculator or for any errors or omissions in connection with its use, and under no circumstances shall Rex Power Magnetics be held liable for any damages arising from the use of, or results generated by, the calculator.
Enter motor horsepower, efficiency, and power factor to calculate required kVA.
Rex Power Magnetics makes no representations as to the accuracy of the information used by or generated by this calculator. The results are provided for general reference only and should be independently verified by a qualified professional before being relied upon. Rex Power Magnetics assumes no responsibility for the results generated by the calculator or for any errors or omissions in connection with its use, and under no circumstances shall Rex Power Magnetics be held liable for any damages arising from the use of, or results generated by, the calculator.
Enter the transformer kVA, secondary voltage, and % impedance to calculate the available secondary fault current.
Rex Power Magnetics makes no representations as to the accuracy of the information used by or generated by this calculator. This calculator uses the infinite-source method and does not account for primary-side source impedance, conductor impedance, or motor contribution; actual fault current may differ. The results are provided for general reference only and should be independently verified by a qualified professional before being relied upon. Rex Power Magnetics assumes no responsibility for the results generated by the calculator or for any errors or omissions in connection with its use, and under no circumstances shall Rex Power Magnetics be held liable for any damages arising from the use of, or results generated by, the calculator.
Enter the harmonic current spectrum to calculate K-Factor, harmonic loss factors (FHL, FHL-STR), and current THD.
Enter the RMS current (A) at each harmonic order.
UL 1561 transformer rating
IEEE C57.110 winding eddy-loss factor (same formula as K-Factor)
IEEE C57.110 other stray-loss factor (uses h0.8)
Current distortion vs. fundamental (IEEE 519)
Rex Power Magnetics makes no representations as to the accuracy of the information used by or generated by this calculator. K-Factor is calculated per UL 1561 and the harmonic loss factors (FHL, FHL-STR) per IEEE C57.110. The results are provided for general reference only and should be independently verified by a qualified professional before being relied upon. Rex Power Magnetics assumes no responsibility for the results generated by the calculator or for any errors or omissions in connection with its use, and under no circumstances shall Rex Power Magnetics be held liable for any damages arising from the use of, or results generated by, the calculator.
Enter the transformer rating and losses to generate an efficiency curve and table. Add the % impedance to also calculate voltage regulation.
| Load | Output (kW) | Losses (W) | Efficiency |
|---|
| Power Factor | Regulation |
|---|
Losses are applied as entered, with no temperature correction, and assume linear (sinusoidal) loading at unity power factor for efficiency, with no adjustment for harmonic or additional stray losses. Voltage regulation is calculated at full load for lagging power factors, deriving %R from the load losses and %X from the entered % impedance. Rex Power Magnetics makes no representations as to the accuracy of the information used by or generated by this calculator. The results are provided for general reference only and should be independently verified by a qualified professional before being relied upon. Rex Power Magnetics assumes no responsibility for the results generated by the calculator or for any errors or omissions in connection with its use, and under no circumstances shall Rex Power Magnetics be held liable for any damages arising from the use of, or results generated by, the calculator.
Compare the annual operating cost of two transformers and find the payback period of the lower-loss unit. Adjust loading and electricity price to update the results instantly.
Enter a price for both transformers to see the payback period and 5-year cost graph.
Annual operating cost reflects the cost of transformer losses only (no-load plus load losses at the selected loading), assumed energized 8,760 hours per year at the stated loss values, with no temperature correction and no adjustment for harmonic or additional stray losses. Energy and purchase prices are estimates entered by the user; actual costs and savings will vary. Rex Power Magnetics makes no representations as to the accuracy of the information used by or generated by this calculator. The results are provided for general reference only and should be independently verified by a qualified professional before being relied upon. Rex Power Magnetics assumes no responsibility for the results generated by the calculator or for any errors or omissions in connection with its use, and under no circumstances shall Rex Power Magnetics be held liable for any damages arising from the use of, or results generated by, the calculator.
Calculate the inductance of a line or load reactor from the system voltage, percent impedance, rated current, and frequency.
Inductance is calculated from the entered percent impedance referenced to the system voltage at the stated frequency, assuming a balanced linear system. Results do not account for saturation, tolerance, temperature, or harmonic effects. Rex Power Magnetics makes no representations as to the accuracy of the information used by or generated by this calculator. The results are provided for general reference only and should be independently verified by a qualified professional before being relied upon. Rex Power Magnetics assumes no responsibility for the results generated by the calculator or for any errors or omissions in connection with its use, and under no circumstances shall Rex Power Magnetics be held liable for any damages arising from the use of, or results generated by, the calculator.
Size the series reactor for a power-factor capacitor bank tuned below a chosen harmonic. Enter the bank rating, system voltage and frequency, and the tuning order.
Tuning order is set below the harmonic to be blocked — common values are 3.78 (7%), 4.2 (5.67%) and 4.7 (4.5%).
The reactor is sized so the series capacitor-reactor circuit resonates at the entered tuning order, derived from the capacitor reactance at the stated voltage and frequency. Results assume a balanced linear system and do not account for capacitor tolerance, reactor tolerance, saturation, temperature, or system source impedance. Rex Power Magnetics makes no representations as to the accuracy of the information used by or generated by this calculator. The results are provided for general reference only and should be independently verified by a qualified professional before being relied upon. Rex Power Magnetics assumes no responsibility for the results generated by the calculator or for any errors or omissions in connection with its use, and under no circumstances shall Rex Power Magnetics be held liable for any damages arising from the use of, or results generated by, the calculator.