Experimental determination of magnetic characteristics of electrical machines

Abstract

A test equipment for determination of magnetic characteristics of different kinds of electrical machines is presented. Experimental determination of magnetic characteristics of electrical machines should be understood, according to the machine studied, as determination of their corresponding inductances or as determination of their magnetization curves (flux-linkage versus current for different rotor positions). The test equipment is based on a method of measurement of inductance by means of D.C. current, proposed by C.V. Jones, in which a bridge arrangement is used in order to eliminate the resistance effects. This equipment is able to obtain armature inductance in DCM (direct current motor), d-axis and q-axis inductance in SPSM (salient-pole synchronous machine) or SYNCREL (synchronous reluctance motor) and magnetization curves of SRM with a good accuracy and in an automatic way. The main advantage of this setup is that it is an automatic system controlled by PC, that allows magnetic characteristics of almost any electrical machine to be obtained, reducing measurement time and manual errors and providing easy and user friendly presentation of the test results. Several examples of experimental determination of magnetic characteristics using the proposed equipment are shown proving their test capabilities.