Articles techniques et présentations

Linear Induction Motor (LIM) has been identified as a key element for electromagnetic launching technology. The stator part of the motor when energized induces a linearly moving magnetic field which consequently produces a thrust force on the rotor part of the motor. Thus it accelerates a projectile to a required velocity in a controllable manner as per the application criteria. In the present work, a 2-D transient and frequency domain magnetic field analyses are carried out in COMSOL Multiphysics Software where a Linear Induction Motor (LIM) is modelled as per the given design parameters. The model consists of linearly arranged copper coils placed in the slotted structure of magnetic core domain of higher relative permeability, which is referred to as 'stator' assembly and a so-called 'rotor' metallic plate (SS) placed above the stator assembly maintaining a clear air gap. Double layer winding of copper coil is simulated as per the actual phase wise winding. Coil current waveform and the current direction is defined as per the 3-phase connection. Quadratic discretization of the magnetic vector potential is adopted in the analyses for better accuracy of the results. The temporal and spatial magnetic flux density and induced current distribution on the SS plate domain are analyzed in the simulation. The time averaged and instantaneous vertical (referred to as Lift Force) and linear Lorentz force (referred to as thrust force) component acting on the SS plate are also estimated in the analyses. The simulation methodology has been established. The simulation results of thrust force experienced by the SS plate have been validated through experimental measurements. A very good agreement between the two has been observed.