DRIVES, MOTORS + SWITCHGEAR
Keeping ladle cranes moving Columbus Stainless, a member of the Spanish based Acerinox S.A Group of Companies, is the only fully integrated, technologically advanced, single-site stainless steel producer in Africa.The plant – located in Middelburg in Mpumalanga – produces a wide range of austenitic, ferritic, utility and duplex grades of stainless steel suitable for many applications and supplied to various final customers, distributors, engineering shops and mines in South Africa and globally.
“ W e have been operating for more than 50 years,” says Stef Du Toit, Columbus Stainless Cranes Engineer. “To remain successful in what we do, we have ensured our facilities can keep up with demand and experience minimal downtime. This means working with the right technology partners.” For more than 20 years, Columbus Stainless has worked with Nidec Control Techniques to ensure its operations run smoothly. Most recently, the Nidec team used its expert en- gineering capabilities to upgrade the main hoist of the steel plant ladle cranes. “These gantry cranes are critical production cranes which carry between 110 and 115 tonnes of molten steel in ladles along the steel making plant. The two main hoist motors are synchronously locked together,” explains Derek Coetzee, Head of Engineering at Nidec Control Techniques. The motors’ control technology needed to be replaced to ensure the facility would remain future-fit and to avoid breakdowns caused by obsolete technology. Nidec was awarded the turnkey contract to upgrade the variable frequency drives with redundancy features – a project usually awarded to a crane company. “We were entrusted with this project based on our strong track record and longstanding relationship with Columbus Stainless. We had the suitable technology, and we made sure we got the right skills on board to deliver the crane load capacity in line with the customer’s requirements,” says Coetzee. A custom engineered solution He explains further. “An interesting aspect of this project was that our solution needed to be able to fit into the same
space as the existing system. Our compact technology put us ahead of our competitors and we were able to engineer a system which could meet the demands of the facility while not disrupting existing structures.” The specific Nidec Control Techniques products used for this application included two Unidrive M700 units connected in parallel, with each driving a 250 kW 8-pole IMfinity premium efficiency induction motor. “The M700 ac drive is a high-performance motor con- trol system providing exceptional control flexibility in high specification industrial applications. Combined with motors which are designed to satisfy most requirements in a de- manding industry, we are confident this solution will help to see Columbus remain an industry leader,” comments Bruce Grobler, Regional Manager of Nidec Control Techniques. A door-mounted HMI provides full diagnostics for the system. Nidec takes pride in its complete turnkey solutions, through which it provides standard and customised drives. It handles small machine automation projects up to com- plete automation and electrical solutions. “With this project, we took into account the operational needs of the client and proposed a solution which would see the operation succeed now and into the future. Furthermore, commissioning went smoothly. Our accredited personnel always ensure the reliability and safety of equipment, and complete installations in compliance with local technical regulations and safety standards,” Grobler adds.
Built for the long-haul The ladle cranes at Columbus Stainless have been oper-
ating for about 25 years, and still have many years of service life ahead – if supported by the right technology. The M700 is Nidec Control Techniques’ flagship drive and has been used in other areas of the Columbus Stainless plant. Stef Du Toit comments that the local availability of the technology is an added bonus. “The drives are critical to our production efficiency and it is important we minimise downtime as far as possible. The availability of spares and support in-country is a huge benefit to us.” □
Compact technology in high-performance drives and motors met the requirements of the facility without disrupting existing structures.
For more information visit: www.nidec.com
14 Electricity + Control MARCH 2022
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