On characteristic signs of damage of thyristor arms of AC electric locomotive power converter

The paper considers characteristic signs of electromagnetic processes at loss of control of rectifier-inverter converter arms used in AC locomotives with collector motors. Evaluation of the power converter serviceability is based on the analysis of energy indicators of the processes and values of harmonic components of the rectified voltage. To study the electromagnetic processes in the power circuit of electric locomotives, a method based on the calculation of transients using the Duhamel integral was used. An analysis of the effect of the phase angle of voltage control on the degree of energy output into the chain of traction motors is conducted. The boundary relations of odd harmonic components of voltage, which allow to fix the fact of thyristor arm control pulses skipping, are determined. Calculated values of ratios of certain harmonics of rectified voltage, allowing to identify the particular arm, which did not open according to the normal control algorithm.