What are the classifications of Rogowski Coil

Rogowski coil is a current sensor used to measure AC high current and high pulse current. Its classification can be done from multiple perspectives, and the following are some of the main classification methods:

1、 Classified by sensing principle

Differential Rogowski coil: Its induced electromotive force is in a differential relationship with the measured current. When the terminal resistance Rm is appropriate, the output voltage of the Rogowski coil sensor is proportional to the rate of change of the measured current.

Self integrating fractional Rogowski coil sensor: Under certain conditions, the self inductance and terminal resistance of the Rogowski coil can form an integral loop, and the output voltage of the sensor is proportional to the measured current.

External integral fractional Rogowski coil sensor: An external integrator is required to integrate the differential output of the Rogowski coil to obtain an output signal proportional to the measured current.

2、 Classified by Form

Rigid Rogowski coil: wound on a hard skeleton, the coil is hard and not easily deformed, the winding is generally dense, and the accuracy is high. However, due to the closed coil, the measurement adaptability is poor.

Flexible Rogowski coil: wound on a flexible skeleton, the skeleton can deform with gaps, the winding is sparse, and the winding accuracy is not as good as that of a hard Roche coil. But it is very convenient for measurement and suitable for various complex environments.

PCB Rogowski coil：By printing the coil on the PCB board, the winding accuracy is greatly improved and the coil position is stable. However, due to the limited space of the PCB board, the cross-sectional area of the coil is small, the number of turns is small, the mutual inductance coefficient is relatively small, and it is significantly affected by temperature.

3、 Classified by purpose and structural characteristics

Fixed Rogowski coil: mainly used to generate a constant magnetic field or as an electromagnetic induction element, its structure and size remain unchanged after manufacturing.

Variable Rogowski coil: used to adjust inductance or frequency, its structure and size can be adjusted or changed within a certain range.

In summary, there are various classification methods for Rogowski coil, and suitable types can be selected according to different needs and scenarios.