Powder coatings based on epoxies and other synthetic resins

  From the ICMEESA archive Powder coatings as a means of finishing metallic objects have gained great popularity in the last five years. Many synthetic resins have been adapted to powders and at least a dozen different systems are currently in vogue overseas. While thermoplastic resins such as vinyl and polythene have been in use […]

Modern power quality issues

  As we connect more electronic devices to our power systems, the quality of the power becomes more complex. Grounding affects voltage stability and, more importantly, is critical to personal safety. Numerous articles have been written on the subject of harmonics. However, these articles do not always address our basic problems in an understandable way: […]

Partial flux – measurement reliability of lensed LEDs

  Most LED manufacturers use units of luminous intensity (cd) for the measurement and classification of LED brightness. This procedure is reliable and reproducible for numerous LED types, but is insufficient for LEDs with narrow emission angle characteristics. This article describes the procedures for measuring luminous intensity, partial flux and luminous flux, along with the […]

Sustainable shaft grounding with variable frequency drives

  Currents induced on motor shafts by variable speed drives (VFDs) can wreak havoc with motor bearings, shortening motor life dramatically and causing costly repairs. A reliable method of shaft grounding is essential to mitigate these currents and realise the full potential of VFDs. In the field of flow control, the potential for increased efficiency […]

Most common wastes in an electro-mechanical system

  According to the US Department of Energy estimates, motors account for 70% of all electricity used by industry. They are prime targets for finding and reducing energy waste because they use so much energy. Electro-mechanical equipment wastes energy in two primary ways: When it is operated more often than necessary. Either by schedule (equipment […]

Switchgear for power factor correction systems

  The importance of differentiating between various circuit types or capacitor assignments to inductive loads when implementing power factor correction (PFC). A differentiation is made between individual PFC and group PFC. With individual PFC, the capacitor is assigned individually or switched to a load. With group PFC, the power factor of a load group is […]

Ilanga II: Under the hood of a sun chaser

  The engineering challenge of designing and building a solar-powered racing car for a strenuous eight-day international endurance race brings together research, theory and development while promoting alternative energy and technological innovation. The Ilanga II is a prototype solar racing car developed by the University of Johannesburg (UJ) Solar Team to compete in this year’s […]

Comparing harmonics mitigation techniques

  A comparison of harmonic mitigation techniques in a range of applications and settings, and theoretical and practical comparisons between active and passive series and shunt filters to reduce harmonic loading in a drive system. Harmonics in power systems are mostly caused by various semiconductor-based loads. Most common loads are drive systems (typically transistor-based variable […]