Motor starters limit the inrush current and provide a managed start of the motor. Modern starters provide much more than just current limitation. The inrush current in 3-phase induction motors varies from five to seven times the rated current. In some applications, this level of inrush current may cause a significant voltage drop in the […]
Power usage effectiveness (PUE) is growing in popularity as an efficiency metric by the data centre market. While PUE is a tool to deploy an approach, or develop an implementation within a data centre, the measurement of PUE and its accuracy could have an increasingly negative impact. Where the energy manager of a data centre […]
Health and cost savings considerations are driving an increasing move towards electric battery-driven vehicles and machinery in underground and opencast mining operations. Battery powered mining vehicles were introduced in the 1980s, but it is only in recent years that large-scale adoption of the technology is being considered. A recent news report states that the market […]
Life extension seems to be a common practice today in generating plant. Changes in the operating mode however requires more than a simple replacement of worn parts. In addition to fundamental repairs of failed parts, life extension can involve repurposing the alternator by upgrading components and monitoring. Extension of life of rotating machinery has to […]
For heating or power generation in turbines, for sterilisation or cleaning purposes – in many sectors, steam is used on a grand scale. It is therefore not surprising that in industry a massive 40% of fossil fuels are used for steam generation in boilers. The judicious use of fuels such as oil or natural […]
The calculation of the incident energy associated with arc-flash hazard has almost universally been conducted in accordance with IEEE1584-2002. It is expected that the heavily revised edition of IEEE1584 will be released in the last quarter 2017 or first quarter 2018. This article discusses the proposed changes to the guide for different electrode configuration […]
The mechanical properties of insulating paper can be established by direct measurement of its tensile strength or degree of polymerisation (DP). These properties are used to evaluate the end of reliable life of paper insulation. This article discusses how to evaluate the status of paper insulation in a power transformer. Analysis of paper insulation […]
Both IT server installations and telecom sites are becoming increasingly power hungry, and the quest for greater efficiency is driving a move away from the classic AC UPS and 48 V DC configurations to systems which offer fewer losses and reduce the amount of equipment to be installed. Systems based on 400 V DC […]
Longer lifespan, reduced size and weight, faster recharge times and declining prices have made lithium-ion batteries an appealing energy storage technology. This article answers some questions new users may have. In the simplest of terms, a battery is an electrochemical device that stores energy and releases it as electricity. Batteries are typically organised in […]
The advantages and disadvantages of the predictive, preventative, and run-to-failure maintenance practices, and how preventative maintenance programmes are enhanced using thermal imagers. Typical predictive maintenance includes tasks such as vibration analysis on machines, acoustic, ultrasonic, and infra-red (IR) thermography inspection on electrical systems. Table 1 provides a comparison of predictive, preventive, and run-to-failure maintenance. […]
