Overview of the Rogowski coil principle

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Overview of the Rogowski coil principle

As illustrated in Figure 2, the Rogowski coil principle states that a conductor carrying an AC

current i(t) and passing through a helical coil, induces a voltage across the coil that is

proportional to the rate of change of the current (di/dt) in the inductor.

Figure 2.

Rogowski coil principle

The voltage v(t) is a function of winding factor (Kr) and the frequency (Fr) of the sinusoidal

waveform i(t).

Equation 1

Kr is determined by the winding characteristics such as cross-sectional area (s), the number

of turns per unit length (n) and the symmetry of the coil. An integration of v(t) gives a

measure, proportional to Kr, of the instantaneous RMS current in the conductor.