  We investigate the influence of the specimen velocity on the magnetic flux
leakage with the aim of selecting the optimum sensor locations. Parametric
numerical simulations where the specimen velocity was in the range [0.1-20]
m$\cdot$s$^{-1}$ were carried out. As the specimen velocity is increased, the
magnetic field varies from being symmetrical to being asymmetric. For the
radial magnetic induction, the peak to peak value moves from the centre of the
bridge towards the direction of the specimen movement. For the axial magnetic
induction, the specimen velocity influence is dependent on the sensor location
and a signal-velocity independent region was discussed.
