Case study: remote condition monitoring of London Underground track circuits

Delivering a reliable remote condition monitoring system for the London Underground to enable maintainers to respond to failures before they occur. London Underground serves 1,7-billion passengers per year and the Victoria Line accounts for 213-million of those journeys. The line carries 89,1-million passengers per year in the peak service, offering the most intensive service on […]

Arc flash mitigation and arc-resistant switchgear

Application of arc-resistant switchgear to help mitigate arc flash hazards can be a very effective way to enhance safety for electrical workers. Not only the selection of protective device types, but also selecting the settings for adjustable devices is important in the mitigation of arch flashing. Settings must be chosen to protect equipment properly while […]

The cost of poor power quality

  Productivity is the key to survival in today’s globally competitive environment. When you think about the basic inputs to production – time, labour and materials – you can see there isn’t much room for optimisation. You have 24 hours per day, labour is costly and you don’t have much choice in materials. Therefore, every […]

Fundamentals of laser welding

  There are two of types of neodymium-doped yttrium aluminium garnet (Nd:YAG) laser welder, continuous wave and pulsed. As the name suggests, continuous wave or CW is either on or off, whereas pulsed lasers create welds by individual pulses. The pulsed laser uses high peak power to create the weld, whereas the CW laser uses […]

An improved approach for connecting VSDs and electric motors

  Motor winding insulation can deteriorate quickly and the motor may fail when variable speed drives are connected to motors by long cable lengths. Within the VSD, AC supply voltage is converted into DC by means of a rectifier. DC power contains voltage ripples which are smoothed using filter capacitors. This section of the VSD […]

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 […]