Designing high-pressure, high-volume pumps for harsh environments

  Pump designs fall mainly into two categories, centrifugal and reciprocating (piston) type, each with its own benefits and constraints. This article explores the design criteria and some of the applications. Information on the application and the fluids involved is key to matching the correct pump design to the application (see Fig. 1). Approaching a […]

Preventing system failure in solar PV systems

  It is vital for solar photovoltaic (PV) systems to accommodate the temperature fluctuations and environmental conditions to which they are typically exposed as these conditions often cause ongoing system failure. The difference between standard test conditions (STCs) and nominal operating cell temperature (NOCT) is of interest here as these values in PV modules determine […]

Reliability and lifetime of LEDs

  With the increasing complexity of technical equipment, modules and individual components, reliability, lifetime and the cost of exchanging and revision become increasingly important for the customer. The single requirement that devices should not fail is no longer sufficient for modern, powerful components or devices. More often, it is an additional requirement that they should […]

Electrical, insulation and thermal measurements for motors and drives

  Electrical, insulation resistance and thermal measurement are three tests which can troubleshoot motors, drives and associated electrical panels and prolong their operational lifetime. Used together, thermal imagers can detect potential problems and insulation resistance, while electrical tests can determine the cause. Handheld thermal imagers can collect heat signatures from a range of motors, from […]

Lightning and surge protection for rooftop PV systems

  Apart from damaging solar photovoltaic (PV) modules, inverters and monitoring elecronics, lightning strikes also lead to field-based and conducted electrical interference. According to the South African Photovoltaic Industry Association (SAPVIA), photovoltaic (PV) is the fastest growing power generation technology in the world. More than 35 GW of PV is installed and operating worldwide, producing […]

Emergency lighting control by means of DALI

  With the global emergence of building automation, the powerful supervisory facilities and control of a DALI-based emergency lighting system in building designs and renovations are now too obvious to ignore. The Occupational Health and Safety (OHS) Act of 1993 states that emergency lighting must be provided in any workplace without natural lighting, that it […]

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 […]