Variable speed drives produce a substantial amount of electrical noise in the form of harmonics. If a drive system is not configured correctly, this will interfere with associated electronic circuits and cause possible malfunctions. Further, especially in systems for tenders, there is a requirement to ensure the harmonics remain below acceptable levels. Ana-Digi offers their customers harmonic simulation analysis as a service for new and existing installations. This requires the utility and user incoming transformer impedance, and V and VA ratings; motor name plate details; and total harmonic distortion maximum levels required (3, 5, 8 or 10%). The analysis result will include a full report on recommended harmonic filters (RFI); THD for voltage and current; and options for 6, 12 or 18 pulse input stage configurations on the drive  markets.

Contact Keith Gross, Ana-Digi Systems, Tel 021 914-9030,