Ohm’s law:

V = I × R

I = V ÷ R

R = V ÷ I

Single-phase AC power:

P (watts) = V (volts) × I (amps) × Power factor

Three-phase AC power:

P 3 ∅ (watts) = V (volts) × I (amps) × Power factor × 1.732

Power factor:

PF = cosine (phase angle) × 100

PF = Power (watts) ÷ [ V (volts) × I (amps)]

PF = Real Power (watts) ÷ Apparent Power (VA)

Apparent power:

Apparent Power (VA) = V (volts) × I (amps)

Peak voltage:

V peak = V rms × 1.414

RMS voltage:

V rms = V peak × 0.7071

Inductive reactance:

X L (ohms) = 2 π ƒ L

where X L is the inductive reactance, π is pi (3.14), ƒ is the frequency in hertz, and L is the inductance in henrys