frequency

T = cycle duration in s

gyro-frequency

phase angle

instantaneous value of a sinusoidal a.c. voltage

instantaneous value of a sinusoidal a.c. current

maximum value

- of a sine-wave voltage

U = virtual value

- of a sine current

I = virtual value

inductive resistance

(inductive reactance)

L in H

capacitive resistance

(capacitive reactance)

C = capacity in F

impedance

[Ω]

ohmic drop in voltage

U_R = I · R

[V]

inductive voltage drop

U_L = I · X_L = I · ω L

[V]

capacitive voltage drop

[V]

Ohm’s law for alternating current

[A]

apparent power

S = U · I

[VA]

active power

P = U · I · cos ζ

[W]

reactive power

Q = U · I · sin ζ

[Var]

power factor

apparent power

[VA]

active power

[W]

reactive power

[Var]

power factor

efficiency for motors and generators

P_e = effective power

P_i = indicated power

speed calculation of three-phase motors rotating field speed

p = number of pole pairs

slip

[%]

n = rotor speed