2．Device to visualise the spatial distribution of magnetic fields

A device has been developed to permit swift measurement of magnetic field distribution or intensity in and outside railway vehicles.
Using a scanning technology and a single magnetic sensor, the magnetic field itself and its location can be accurately detected and located.
A matrix approach is then applied whereby the magnetic field distribution and intensity can be directly visualized.

There is currently considerable activity to regulate magnetic fields in railways, such as the 2012 publication of “regulations governing railway electromagnetic fields” from the Ministry of Land and Transport. These regulations impose limit values on the magnetic fields emanating from railway related trackside electric equipment, inter alia, and more broadly have a wide sweeping effect on equipment design and renovation.

Up until today, measuring the magnetic fields in and outside railway vehicles not only required special knowledge but also special devices, none of which made it possible to actually see either the distribution or the force of the magnetic field. Consequently, steps were taken using matrix and scanning techniques to develop a device for measuring magnetic fields.

The scan approach uses a position detector to determine a set of spatial coordinates, and the magnetic sensor simultaneously measures the magnetic field. Data is is then collected onto a PC via an interfacing device (Fig.1).

The matrix approach on the other hand where the magnetic sensor and white circles arrayed in Fig.2 can be used to detect magnetic field sources since it is user-friendly, light weight, compact and power saving.

The devices described above can also be used for measurement on real vehicles in movement, and are expected to become effective tools in future railway magnetic field related investigations.

Fig.1 Scan approach set up and example of measurement result
Fig.2 Example of matrix approach