Electricity + Control August 2016

ENERGY + ENVIROFICIENCY

ROUND UP

Stationary Battery Basics: jars and straps

There is so much terminology related to stationary batteries and it is hard to know what everything means. So, what’s the difference is between jars and straps? What is a jar? A stationary battery jar is the container that holds the cell or group of cells and electrolyte. It is also commonly referred to as a battery case or cell case. Jars are typically made out of some kind of ther- moplastic substance. However, hard rubber is sometimes used as well. If the battery contains nickel-cadmium cells, the jar may even be made out of steel. Vented lead-acid batteries normally have transparent jars to allow for plate and sediment inspection. What is a strap? A stationary battery strap is the component in a cell that joins plates of like polarity in parallel. It is an electrical conductor that is made of copper. It typically has a lead or tin plating for lead-acid cells. Nickel-cadmium cells require a different connector. They are typi- callymade with nickel-, cadmium-, or tin-plated copper, or even steel bar. Occasionally, the strap may be insulated copper wire or lead (with or without a copper insert) for lead-acid batteries, depending on the manufacturer’s specifications. Stationary batteries Transportation batteries function as start/stop batteries. The primary discharge occurs when the vehicle is started. After that, it spends the rest of the drive time recharging. Motive power batteries do not operate this way. Instead of only being used to start the machinery, there is a continual discharge. Stationary batteries are used con- stantly while in operation and used until depleted, or until the job is done, and then recharged after use. Midtronics electrical system testing technology is used by six major automotive manufacturing

facilities in South Africa in on-vehicle equipment, recording events that may lead to battery or electrical system failure. In addition to this, two leading SouthAfrican battery manufacturers and distribu- tors have committed to using the Midtronics technology in their facilities and distribution outlets. Comtest is Midtronics’ accredited partner in southern Africa. Enquiries:The Comtest Group onTel, +27 (0) 10 595 1821 or email sales@comtest.co.za

Klipheuwel research facility for wind energy technology decommissioned For the past 13 years Eskom’s Klipheuwel Wind Farm, situated on theWest Coast near Cape Town, has served as a valuable re- search facility for wind energy technology and has contributed 3 MW to the Eskom plant mix. in the industry. The remainder of the wind farm (land and two Vestas wind turbines) will be disposed of following Eskom’s com- mercial processes. Enquiries: Eskom Media Desk. Tel: +27 (0) 11 800 3304 / 3343 or email mediadesk@eskom.co.za

farm was transferred to Peaking (Genera- tion Division) to operate and maintain.The Klipheuwel Wind Farm provided an excel- lent platform for learning in this type of renewable technology. This learning has helped inform the business in its decision- making for other larger projects such as the Sere Wind Farm. Valuable operational and maintenance experience has been gained through this facility. Since the commer- cial operation of the facility, the plant has reached the end of its useful life and Eskom is in the process of decommissioning this demonstration facility. How it will end One of the turbines will be used for practi- cal training at the South African Renewable Technology Centre (SARETEC), the only renewables training facility in South Africa and is situated in Bellville, Cape Town. There will be an opportunity for learning to continue and to broaden the skills base in South Africa and help enable development

With these objectives achieved and the new 100 MW Sere Wind Farm delivering excellent results, the time has come to decommission the three wind turbines at Klipheuwel. The decommissioning of the first turbine took place on 18 July 2016. Where it started In 2002, Eskom’s Resources and Strategy Division erected three wind turbines as a demonstration wind farm facility at Klipheu- wel. The intent of the wind farm was to conduct research on the potential of wind energy as an electricity generating option as well as to evaluate the different wind-based technologies and their economic viability. In 2006, once the research was com- pleted, the ownership of Klipheuwel wind

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