Measuring the parameters of a cage-rotor reluctance synchronous motor

A three-phase two-pole line-start conventional rotor reluctance synchronous machine that comprises a cage was tested in the laboratory for the determination of its dynamic characteristics. The purpose is to obtain the machine equivalent circuit for synchronous and asynchronous operation modes. The vector diagram is the theoretical approach that is used in this work to get the synchronous performance modeling of the machine. Among other parameters with straightforward measurement procedures, the d-axis and q-axis machine reactance are required in the model. It is well known that the measurement of some parameters of cage-rotor machines may present some difficulty owing to the distortion that is introduced by the cage. The q-axis is one of these critical parameters to be measured. The question is how to obtain accurate parameter values from measurements if a damper or a cage is present. In this work the d-axis reactance was obtained via the conventional no-load test. As for the determination of the q-axis reactance, the steady-state no-load and load tests devised by V.B. Honsinger (1971) were applied. The variation of some parameters with the frequency was obtained by feeding the machine with an inverter. Different stator voltages were applied as well. The torque-speed curves of the machine were also obtained. The setup details a list of the measured parameters and other results are presented in the paper.