This article explores how the cost of condition monitoring for motors can be optimised through examination of the value of each test performed. Part I of this article (see Vector, January 2019, page 24) explores reliability-centered maintenance; the ideal frequency of condition monitoring, the management of spares, assessment of motor efficiency and the risk of […]
Variable speed drives (VSDs) usually consist of a variable frequency source derived from the main supply by means of a DC converter. Techniques using magnetic coupling allow the motor to be run at its optimum speed while supplying a VSD to the load, as well as providing mechanical separation of motor and load. Magnetic couplings […]
To safeguard their future, mining companies must improve performance, cut production costs, reduce environmental impact, and increase automation. Mining companies face major challenges in terms of sustainable growth. As demand for commodities exceeds supply, mining companies search for new deposits in remote and inhospitable regions where production costs are high. In addition, they seek to […]
This article explores how the cost of condition monitoring can be optimised through examination of the value of each test performed. Treating every motor on a site with the same degree of condition monitoring is neither necessary nor financially realistic. The reliability-centered maintenance (RCM) method [1] uses the answers to seven basic questions to determine […]
This article considers the technologies and topologies of MV drives, their advantages, disadvantages, and their impact on the quality of energy on the mains and motor sides. Part 1 of this article explores the line-side topology of MV industrial VSDs (see Vector, October 2018, page 32). On an MV drive with a motor-side filter capacitor, […]
Worldwide demand for energy is expected to double by 2050. At the same time, governments must halve their countries’ CO2 emissions to halt climate change. According to the International Energy Agency (IEA), electric motors account for 40% of total global electricity consumption, far more than lighting, a far better-known culprit, which weighs in at just […]
IEC standards now recommend that surge protective devices be installed at the supply point of the facility. The publication of the installation standards IEC 60364-4-44 and IEC 60364-5-53 in September 2015 motivated the use of surge protective devices (SPDs). This requirement is no longer just valid for commercial and industrial facilities, but also applies to […]
Which is more cost-effective in reducing energy consumption and providing the most satisfactory payback time in pump applications, frequency converters or soft starter technologies? In water applications, centrifugal pumps are driven by induction motors fed directly from the network. Flow regulation is accomplished by a few different means, namely throttling, a highly inefficient method as […]
With an estimated 2-billion units installed, small motors (<750 W) are reported to account for 90% of the global electric motor population [1]. Small electric motors of up to 1 kW output are central to a large number of applications and are installed as drive elements in many types of end-user and industrial equipment. Permanent […]
A closer look at soft starters and VFDs, their advantages, disadvantages and applications. A large starting current may be required (typically 5 – 7 x FLC) when accelerating an AC motor to full speed using a full voltage connection. Additionally, the torque of the AC motor is mostly uncontrolled and can shock the connected equipment, […]
