Rotor Induction Machine Research Articles

Neural networks aided on-line diagnostics of induction motor rotor faults

An improvement of induction-machine rotor fault diagnosis based on a neural network approach is presented. A neural network can replace in a more effective way the faulted machine models used to formalize the knowledge base of the diagnostic system with suitably chosen inputs and outputs. Training the neural network by data obtained from experimental tests on healthy machines and from simulation in the case of faulted machines, the diagnostic system can discern between healthy and faulty machines. This procedure replaces the formulation of a trigger threshold, required in the diagnostic procedure based on the machine models. >

A magnetic bearing system using capacitive sensors for position measurement

A capacitive sensor system for use in a bearingless induction motor is presented. Details of the circuit design are presented, and a theoretical step response is calculated and compared with experimental results. It is shown that one-dimensional position stability of an induction machine rotor can be obtained by controlling the currents in diametrically opposed conventional stator windings. In the case considered, the weight of the rotor was supported by a state current of 33% of the rated value. A margin is therefore available for the addition of a rotating component of current. The rotor of this machine has been reduced during development of the position sensor. It is anticipated that the system could be implemented with a smaller airgap and consequently a smaller steady-state current. The position signal was satisfactorily obtained using a simple airgap-mounted position-sensing system. An approximate model of the nonlinear system is sufficient for predicting the closed-loop step response for small perturbations.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Identification of principal factors causing unbalanced magnetic pull in cage induction motors

The precise effect of the static eccentricity of the rotor of an induction machine on the magnetic field in the airgap is demonstrated and explained. The relation between the unbalanced pull and the eccentricity of a cage rotor is determined through measurements of the electromagnetic field at the rotor surface, and the significance of the tangential-flux component in the machine airgap is assessed.