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Electrical & Controls
Motor current, cable voltage drop, power, 4–20 mA and PLC scaling, RTDs and circuit basics. 24 free tools.
Basics 7
Ohm's law calculatorEnter any two of voltage, current and resistance; get the third plus power.AC power calculator (kW, kVA, kVAR)Real, apparent and reactive power from voltage, current and power factor.Resistors in series and parallelTotal resistance for any list of resistors, in series or in parallel.RC time constant calculatorTime constant and charge time for a resistor–capacitor circuit.Capacitor discharge time calculatorTime for a capacitor to bleed down to a safe voltage, and stored energy.Voltage divider calculatorOutput voltage and current of a two-resistor divider.Inductive and capacitive reactance calculatorXL, XC and resonant frequency at any frequency.
Motors & drives 6
Motor full-load current calculatorThree- or single-phase motor current from kW or hp, voltage, PF and efficiency.Motor synchronous speed and slipSynchronous speed from poles and frequency, and slip from actual speed.VFD frequency to speed calculatorMotor and machine speed at any drive output frequency.Motor running cost calculatorAnnual energy use and electricity cost of a motor.Star (wye) and delta voltage and currentPhase voltage and current from line values for star or delta windings.Motor starting current calculatorInrush current for DOL, star-delta, soft starter and VFD starting.
Power & cables 8
Cable voltage drop calculatorVoltage drop and percentage for copper or aluminium cables.Transformer full-load currentPrimary or secondary full-load current from kVA and voltage.Power factor correction (kVAR) calculatorCapacitor kVAR needed to raise power factor to a target.AWG to mm² wire gauge converterAmerican wire gauge to mm² and diameter, and mm² to the nearest AWG.Battery and UPS runtime calculatorEstimated runtime from battery capacity, voltage and load.Transformer short-circuit current (estimate)Maximum secondary fault current from kVA and impedance.Power consumption and energy costkWh and cost for any load running for set hours.Heater element power (star / delta)Heater bank power and current from element resistance, or the resistance you should measure.