Principles and testing methods of earth ground resistance

Poor grounding contributes to downtime but a lack of good grounding is also dangerous and increases the risk of equipment failure. Over time, corrosive soils with high moisture and salt content and high temperatures can degrade ground rods and their connections. So, although the ground system had low earth ground resistance values when initially installed, […]

Clever pumping: making water industry’s pumps intelligent

  Climate change, increasing water demands due to global urbanisation, and the legal obligations of the EU’s Water Framework Directive are all making the water sector an attractive arena for technologies that can help reduce costs and contribute to reducing the effects of climate change. It is against this backdrop that the demand for intelligent […]

Improving motor efficiency

  Some 20% of the estimated 65% of industrial energy used by electric motors is lost by wasteful throttling mechanisms, making it essential to reduce the energy appetite of motors. Energy consumption by electric motors can be reduced in two main ways – efficient control of the speed at which they run, and making the […]

Thermal measurement guidelines for LEDs

  Guidelines for the thermocouple attach to measure the solder point temperature and the calculation of the approximate LED junction temperature for various LEDs. One of the most critical design parameters in an LED illumination system is its ability to draw heat away from the LED package. High operating temperatures at the LED junction affect […]

Light pollution in South Africa: 2011 versus 2001

  This article outlines how artificial skyglow, also known as light pollution, is modelled using Census 2001 and Census 2011 population data. Light pollution is defined as “any adverse effect of artificial light including skyglow, glare, light trespass, light clutter, decreased visibility at night, and energy waste” [1]. This work, illustrated here, is a follow-up […]

The ABCs of multimeter safety

  Often, users accidentally subject their multimeters to much higher voltage than they think they are measuring. This submits the units to momentary high-voltage spikes, causing them to fail. The possibilities of transient overvoltages increase as distribution systems and loads become more complex. Motors, capacitors and power conversion equipment such as variable speed drives (VSDs) […]

Some developments in winder brake control

  From the ICMEESA archive Methods of control for low and high pressure hydraulic braking systems which have been applied successfully to a number of hoists in South Africa. This article describes new and simplified control systems for low pressure and high pressure hydraulic braking systems with emphasis on air brake and low pressure oil […]

How to size a generator set

  Many factors influence generator set sizing, making it time consuming to manually calculate required generator capacity. Parameters that determine the required generator set size include minimum generator set load; maximum allowable step voltage dip and step frequency dip; altitude and temperature; duty cycle, fuel, phase, frequency and voltage. Sizing software, such as Cummins Power […]

Bloodhound SSC: a supersonic engineering marvel

  A hybrid jet-and-rocket powered vehicle will fire up its 135 000 hp engines to break the sound barrier and the world record alike in a 1600 km/h race at Hakskeen Pan, South Africa. The 14 m, 7 tonne Bloodhound supersonic car (SSC) was designed and is being built by the Bloodhound Project, described as […]