01
kW ↔ HP Converter
Quick motor power conversion
Energicity Engineering Toolkit
Free Electrical Engineering Calculators
20 lightweight browser-based tools for current, power factor, APFC kVAR, transformer, DG, cable, voltage drop, motor, fault current, maximum demand and rooftop solar calculations.
Preliminary calculations only. Final engineering selection must consider applicable standards, equipment data and actual site conditions.
02
Single-Phase Current
Current from kW, voltage, PF and optional efficiency
Use efficiency 1.00 when kW is electrical input power. For motor shaft-output kW, enter the motor efficiency.
03
Three-Phase Current
Current from kW, voltage, PF and optional efficiency
Use efficiency 1.00 when kW is electrical input power. For motor shaft-output kW, enter the motor efficiency.
04
kW / kVA / kVAR / PF
Power triangle calculator
05
APFC Capacitor kVAR
Power factor correction requirement
06
Capacitor Bank Current
3-phase capacitor current from kVAR
07
Transformer Size
Preliminary kVA sizing with margin
08
Transformer Full-Load Current
Primary/secondary current check
09
DG / Generator Size
Running-load kVA estimate
10
Preliminary Cable Size
Current-density + voltage-drop screening
Screening only; final ampacity depends on installation, ambient temperature, grouping, insulation, harmonics and short-circuit withstand.
11
Voltage Drop
AC voltage drop using R and X
12
Transformer Secondary Fault Current
Approximate terminal short-circuit current
Approximation excludes upstream/cable impedance, motor contribution and X/R effects.
13
MCB / MCCB Preliminary Rating
Next standard current rating from design current
Final breaker selection requires cable ampacity, fault rating, trip curve/settings and discrimination.
14
Motor Contactor & OLR Guide
FLC and preliminary AC-3 selection aid
Use motor nameplate current and manufacturer AC-3/overload data for final selection.
15
Earthing Conductor — Adiabatic Check
S = I√t / k
Verify the correct k-value for conductor material, insulation and temperature limits.
16
Motor Starting Current
DOL, star-delta, soft starter or VFD estimate
Actual starting current varies by motor design, load torque and starter settings.
17
3-Phase Unbalance
Voltage or current unbalance percentage
18
Connected Load & Maximum Demand
Demand-factor based estimate
19
Power from Voltage & Current
Calculate kW, kVA and kVAR
20
Rooftop Solar Size & Simple Payback
Energy-offset sizing and payback estimate
Simple estimate only; actual output/economics depend on roof, shading, losses, tariff/net-metering rules and financing.
When a quick calculation is not enough
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Calculator results are only a starting point. For power-factor problems, harmonics, abnormal loading, overheating, protection concerns or high electrical cost, measured site data should take priority.
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This toolkit is designed for engineers, technicians, electrical contractors, maintenance teams and facility managers who need quick preliminary calculations involving current, power factor, APFC sizing, transformer loading, generator sizing, cable screening, voltage drop, short-circuit current, motor starting, phase unbalance, maximum demand and rooftop solar.
Disclaimer: These calculators are general engineering aids and do not replace a site study, approved design, statutory requirement, OEM recommendation or professional engineering judgement.