Analytical model for estimation of eddy current and power loss in conducting plate and its application

Abstract

A model is developed to study the eddy current induced in a thin conducting but nonmagnetic plate of finite size when exposed to a time varying magnetic field. The applied field may be uniform or vary in space. This model can accurately estimate the eddy current contour in the plate and loss due to eddy current. Power losses for plates of various dimensions and at different frequencies are calculated to establish the accuracy of the model. We have also calculated the magnetic field generated by the induced eddy current when the plate of finite size is placed between the two parallel poles of a dipole magnet made of magnetic material of very high permeability. The force acting on the plate due to the interaction of the induced eddy current and the applied external field is also calculated. The model can predict the time variation of force and eddy current. The model may be applicable to understand the effect of eddy current on the vacuum chamber of an accelerator. Various other applications, where this model is useful, are also reported. The results are compared against the results obtained by a simulation using a finite element based code. Here the rectangular plate is considered but the model can be applicable for other geometries as well.

Limitations and Constraints of Eddy-Current Loss Models for Interior Permanent-Magnet Motors with Fractional-Slot Concentrated Windings

“…Similar solutions are reported in [20,26] where in [20], the solution is applied on two IPMs with distributed windings. The resulting average eddy-current losses for a magnet segment become [20]:…”

“…Furthermore, the increase of PM length from l m = 10 mm to l m = 30 mm rules out all but two combinations of p and Q s . Further, the loss densities reported in Tables 1 and 2 are predictions using Model C. However, using Figure 3 or its approximation (26), it can be determined that Model A provides sufficient accuracy (i.e., within a 20% deviation from Model B and Model C) for all cases considered in Tables 1 and 2. (compiling results from [8,10,29,30]) is, for completeness, described in this appendix.…”

“…The contours for ε A|B = 0.2 using the approximation (26) are plotted in Figure 4. Comparing Figures 3 and 4, it can be seen that (26) represents the model prediction error reasonably well.…”

Force on a storage ring vacuum chamber after sudden turn-off of a magnet power supply

“…This point is the huge force acting on a chamber that arises due to the eddy current [1]. Eddy current will arise when the magnets are excited with harmonic or transient current.…”

“…If the magnets produce a time varying field then it will generate an eddy current in the vacuum chamber which in turn modifies the B field produced by the accelerator magnets. That can cause disturbance to the circulating beam [1][2][3]. Beam position monitors (BPMs) are mounted at vacuum chambers to detect the position of the particle beam.…”