Teledyne LeCroy had introduced a new harmonics calculation option for its Motor Drive Analyzer (MDA800) series. This optional software package enhances the standard capabilities of the Motor Drive Analyzer software by adding: advanced harmonic filtering for AC input and drive output numeric table measurements; total harmonic distortion measurement parameters for voltage, current and power; and a new harmonic order table with spectral waveform displays.
The standard Motor Drive Analyzer software provides either full spectrum (no harmonic filter applied) or fundamental only harmonic filters. The new option adds a fundamental+N and a range filter. The fundamental+N filter allows the user to specify how many (N) harmonics from the fundamental to include in the numerics table calculations. The range filter is very similar, but differs in that it allows the user to specify a starting point for the range other than the fundamental.
These filters provide the flexibility and capability drive engineers need to isolate measurements and behaviors to specific frequency bands in order to understand the harmonic heating effects in a motor winding, or to isolate specific harmonics and correlate them to specific drive behaviors. This approach is superior to a simple low-pass filter with limited filtering selectability, especially for a variable frequency drive output where the output frequency changes dramatically under different operating conditions, making simple low-pass filters nearly useless.
November 13, 2015
