The global site of the UK's leading magazine for automation, motion engineering and power transmission
13 July, 2024

Twitter link

ABB buys ring motor business to boost its gearless mill drives

30 July, 2013

ABB is buying Alstom’s ring motor business to enhance its gearless mill drive (GMD) activities. The business, based in Bilbao, Spain, has about 120 employees and achieved a turnover of €57m in 2012/13. It will become part of ABB’s Process Automation division. The financial details of the deal have not been revealed.

Gearless mill drives are used by the ining industry to process ore to extract metals such as copper, gold, platinum, iron and molybdenum. The market for GMD systems is expected to grow because of the rising demand for minerals in emerging countries as they industrialise.

Deeper mines with more complex ore bodies and lower ore grades need to grind more material to yield the same volumes of metal. GMD systems address the need for high ore throughputs.

“The acquisition will combine the leading ring motor product from Alstom with ABB’s electrical offering for GMD systems, enabling ABB to enhance its position as a strong vertically-integrated systems provider,” says Veli-Matti Reinikkala, head of ABB’s process automation division. “The acquired expertise and market strength will provide new opportunities for growth.”

Alstom says that sale of its ring motors business will allow it to refocus on its activities in Bilbao on hydro-electric power. As part of its agreement with ABB, Alstom will relocate these activities to another site in the city.

“The sale of the ring motors activity to ABB is the best solution to guarantee the future of this activity in Bilbao,” says Alstom Renewable Power president, Jerôme Pécresse. “Alstom, as the global leader in hydropower energy, will focus on the growing hydropower market, strengthening its commitment to industrial development in the Basque region.”

ABB says that Alstom’s ring motors will complement its existing electrical offering for GMD systems. The acquisition will bring know-how, experience and technology that that will allow ABB to increase its manufacturing capabilities and strengthen the ring motor business.

A 22.4MW GMD system at a copper mine in Chile

Gearless mill drives eliminate the mechanical components of conventional mill drives. By mounting the rotor poles directly onto the mill, the mill becomes the rotor of the gearless motor. The speed of the large synchronous machines – also known as a wrap-around or ring motors – is controlled using power electronics and magnetic fields.

With no mechanical interaction between the stationary and rotating parts, there is a significant reduction in the amount of energy used, fewer parts and higher reliability. Motors for such applications are already available in ratings up to 28MW. Such motors are powerful enough to rotate a 12.8m SAG (semi-autogenous) mill at 8.9rpm. A mill of this size can process 130,000 tonnes of copper ore per day, producing 163 tonnes of pure copper when smelted.

Power losses in a 16MW GMD system are about 45% lower than those of a conventional 16MW fixed-speed mill drive system. The GMD system also needs less maintenance and typically offers 2.7% more availability per year than a 16MW fixed-speed mill drive system.

Raw material from the crushing stage is typically fed to SAG, AG (autogenous) and ball mills for further processing to break the rock into smaller pieces. These mills are large rotating cylinders, 10–15m in diameter. They can grind hundreds of tonnes of ore per hour. For effective grinding, these mills rotate at low speeds.

  • To view a digital copy of the latest issue of Drives & Controls, click here.

    To visit the digital library of past issues, click here

    To subscribe to the magazine, click here



"Do you think that robots create or destroy jobs?"



Most Read Articles