Achievement of Fast Rise Time Pulses Using Conventional Impulse Generator

Abstract

The increased use of power electronics devices in electrical systems as well as industrial drives leads, for applied electrical machines, to a special kind of electrical stress. Besides a lot of other parameters that electrical stress may be characterized by so-called steep front pulses with rise time much lower than 1μs. Therefore, for quality assessment of components of electrical machines and, in particular, formwound stator coils of electrical motors, related standards content testing procedure by impulse testing with front times less than 0.3μs. The achievement of such pulse parameter using a commercially available impulse generator requires some special measures which are described in detail in the paper. As expected, the main impact on achieving the required value of front time is given by the resulting circuit inductivity, which must be reduced drastically. It was shown that the reducing of the circuit inductivity is not only dependent on applied performance of test generator, but also on the local arrangement of sample under test. The practical measures were confirmed by simulation of test circuit arrangements using appropriate software tools like ATP and MATLAB.