Metallized polypropylene film capacitors are prone to failure under high pulsed voltage and current waveforms. A set of specifications are given by the International Electrotechnical Commission (IEC) that defines the required performance characteristics of these capacitors. The proposed test setup is very involved and requires a skilled operator who is responsible for ensuring that the prescribed test conditions are accurately applied to the capacitor. Automated test and measurement equipment was developed to conduct these tests according to the IEC specifications. The test equipment generates large crest factor current discharge waveforms in the capacitor with peaks reaching 1000 A. A new method was also developed for measuring the rms value of these current waveforms using a low-end microcontroller, together with an inexpensive current transformer. The recommended IEC discharge circuit is powered by a switching power supply, utilizing feedback control, which also enables the rms current through the capacitor to be regulated. By automating the system, important responsibilities are isolated from the operator, allowing a less skilled person to effectively conduct the capacitor tests. / Prof. W.A. Cronje Prof. I.W. Hofsajer
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:uj/uj:7077 |
| Date | 13 May 2008 |
| Source Sets | South African National ETD Portal |
| Detected Language | English |
| Type | Thesis |
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