ABB announced the acquisition of Alstom’s ring motor business to enhance its gearless mill drive (GMD) system business. The parties agreed not to disclose financial details of the transaction. The business, based in Bilbao/Spain, has about 120 employees and will become part of ABB’s Process Automation division.
Gearless mill drive systems are used in the mining industry for processing large quantities of ore to extract metals such as copper, gold, platinum, iron and molybdenum (Fig. 1). The market for GMD systems is expected to grow due to rising demand for minerals in emerging countries undergoing industrialization. Deeper mines with more complex ore bodies and lower ore grades require the grinding of increased amounts of material to yield the same volumes of metal.
GMD systems are designed to address the need for extremely high ore throughput, reliability and availability of the grinding circuit. “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,” said Veli-Matti Reinikkala, head of ABB’s Process Automation division. “The acquired expertise and market strength will provide new opportunities for growth.”
The ring motor product and ABB’s current electrical offering for GMD systems can only work in combination and are therefore fully complementary. The know-how, experience and technology that this acquisition brings will enable ABB to increase manufacturing capabilities and strengthen the ring motor business. In the long term, end users will enjoy the benefits of ABB’s enhanced product quality control and system performance.
The GMD eliminates all mechanical components of a conventional mill drive system. By mounting the rotor poles directly onto the mill, the mill itself becomes the rotor of the gearless motor. The gearless motor – also called wrap-around motor or ring motor – is a very large synchronous machine which uses power electronics and a magnetic field to control the speed of the motor rotation. 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. The motor power, so far, can go up to 28 megawatts for such an application. An infographic of the ring motor and further visual materials can be found here. Raw material from the crushing stage is typically fed to SAG (semi-autogenous), AG (autogenous) and ball mills for further processing to break the rock into smaller pieces. These mills are large rotating cylinders, from 10 to 15 meters in diameter. They can grind hundreds of tons of ore per hour. For effective grinding, these mills rotate at low speeds (Fig. 2).