Interharmoniczne generowane przez maszynę indukcyjną ze statyczną lub dynamiczną ekscentrycznością

Calculations have been based on dynamic, circuital model of cage induction machine, with account for both the double sided slotting and static and dynamic eccentricities. Calculations included startup followed by prolonged steady state, for which harmonic analyses of stator currents have been done. These spectra have been compared with those obtained from diagnostic analyses of currents registered for machines operated in auxiliaries of one of the power plants. Diagnostic analyses referred to the machines of these rated powers and pole pairs: 3.15 MW, p= 1, 400 kW, p= 2, 400 kW, p= 4, 550 kW, p= 4, 300 kW, p= 5. The for calculations indispensable parameters have been obtained from manufacturers. Interpretation of the spectra received from calculations was based on the so called specific harmonic balance model. It refers to the non-slotted machine, without parallel branches. However, it turned out that it is a good starting point for interpretation of the spectra of machines not fulfilling these assumptions. In particular, it was concluded that the so called rotational harmonics are generated only by simultaneous presence of static and dynamic eccentricities. Hence, they are multiplicative, and not additive, results of these eccentricities.