Inductive coupling: Difference between revisions
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== Definition == | == Definition == | ||
The disturber and the victim are coupled by a magnetic field. The level of disturbance depends on the current variations (di/dt) and the mutual coupling inductance. | The disturber and the victim are coupled by a magnetic field. The level of disturbance depends on the current variations (di/dt) and the mutual coupling inductance. | ||
Inductive coupling increases with: | |||
*The frequency | *The frequency | ||
*The proximity of the disturber to the victim and the length of the parallel cables, | *The proximity of the disturber to the victim and the length of the parallel cables, | ||
| Line 12: | Line 11: | ||
== Examples == | == Examples == | ||
(see {{FigRef|R36}}) | |||
(see | |||
*Nearby cables subjected to rapid current variations (di/dt) | *Nearby cables subjected to rapid current variations (di/dt) | ||
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*Inductors | *Inductors | ||
{{FigImage|DB422802_EN|svg|R36|Example of inductive coupling}} | |||
== Counter-measures == | == Counter-measures == | ||
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*Shield the disturbing cables, the victim cables or both (the shielding must be bonded) | *Shield the disturbing cables, the victim cables or both (the shielding must be bonded) | ||
*Reduce the dv/dt of the disturber by increasing the signal rise time where possible (series-connected resistors or PTC resistors on the disturbing cable, ferrite rings on the disturbing and/or victim cable) | *Reduce the dv/dt of the disturber by increasing the signal rise time where possible (series-connected resistors or PTC resistors on the disturbing cable, ferrite rings on the disturbing and/or victim cable) | ||
Latest revision as of 09:49, 22 June 2022
Definition
The disturber and the victim are coupled by a magnetic field. The level of disturbance depends on the current variations (di/dt) and the mutual coupling inductance.
Inductive coupling increases with:
- The frequency
- The proximity of the disturber to the victim and the length of the parallel cables,
- The height of the cables with respect to a ground referencing plane,
- The load impedance of the disturbing circuit.
Examples
(see Fig. R36)
- Nearby cables subjected to rapid current variations (di/dt)
- Short-circuits
- Fault currents
- Lightning strikes
- Stator control systems
- Welding machines
- Inductors
Fig. R36 – Example of inductive coupling
Counter-measures
- Limit the length of parallel runs of disturbers and victims to the strict minimum
- Increase the distance between the disturber and the victim
- For two-wire connections, run the two wires as close together as possible
- Use multi-core or touching single-core cables, preferably in a triangular layout
- Position a PEC bonded at both ends and between the disturber and the victim
- Use symmetrical transmission systems on correctly implemented, symmetrical wiring systems
- Shield the disturbing cables, the victim cables or both (the shielding must be bonded)
- Reduce the dv/dt of the disturber by increasing the signal rise time where possible (series-connected resistors or PTC resistors on the disturbing cable, ferrite rings on the disturbing and/or victim cable)
