Magnetic and Electric Characterization of Materials for Electrical Machines by M.S.Muhit -Royal Institute of Technology School of Electrical Engineering Electrical Machines and Power Electronics

Magnetic and Electric Characterization of Materials for Electrical Machines 
by M.S.Muhit
 Master Thesis
Royal Institute of Technology School of Electrical Engineering Electrical Machines and Power Electronics Stockholm, August 2011
 Abstract
This thesis aims to characterize materials for electrical machines. Electromagnetic properties (b-h curves) and electrical resistivity were the main properties investigated in the project work. Two types of samples are considered: stator lamination sheet and rings made of steel used for structural pieces in large AC machines. To facilitate magnetic characterization experiments, an existing test setup was upgraded. Sensors and amplifiers have been developed. The control system has been upgraded and developed SIMULINK modules have been adapted to dSPACE GUI. The retrieved ‘B’ and ‘H’ signals are processed offline to obtain the results. The lamination sheet has been tested for frequencies in the range [0.1-150 Hz] and flux density levels up to 1.5 T. The obtained results depict characteristics hysteresis curves and measured loss figures. The ring samples (structural steel) are characterized to explore the B-H curves at frequencies in the range [0.1-250 Hz] and field intensity up to 900 A/m. For resistivity measurements of the lamination sheets and ring samples, standard resistivity measurement techniques have been implemented. Keywords Magnetic properties, Epstein frame, hysteresisgraph, four point probe, resistivity measurement, soft magnetic material, electrical steel.
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