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C. Kral, R. Wieser, F. Pirker, M. Schagginger:
"Sequences of Field Oriented Control for the Detection of Faulty Rotor Bars in Induction Machines";
Talk: AMC, Coimbra, Portugal; 1998-06-01 - 1998-07-01; in: "5th International Workshop on Advanced Motion Control", (1998), 1.

Rotor cage asymmetries of induction machines cause disturbances of the air gap flux pattern. These deviations affect torque and speed as well as stator terminal voltages and currents. The proposed fault detection technique senses the actual machine state with the help of real time space phasor models. The Vienna Monitoring Method compares on-line a voltage model output with a current model and observes the deviations in a rotor fixed reference frame. High accuracy and robustness allows the detection of a faulty rotor bar out of the switched voltage and current signals of an inverter fed machine in an early state. The focus of this paper is the detection of a single rotor bar increase under transient speed conditions without the necessity of a clutched load. During an inverter controlled accelerating, lasting 200ms only, the Vienna Monitoring Method evaluates currents, voltages, and rotor position for the calculation of an indication quantity that allows a reliable detection. As one acceleration task only does not excite ever rotor cage bar sufficiently, a set of acceleration and deceleration cycles has to be driven.