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MOTORS & DRIVES 56 E&MJ; • APRIL 2016 www.e-mj.com can be used as well, providing a level of redundancy and safeguarding production. ABB's New Gearless Conveyor Motor While ABB provides a full product line of motors, transformers, variable frequency drives and other equipment to the min- ing industry, the company has chosen to highlight a new gearless conveyor motor for medium-powered conveyors. To be unveiled at this year's bauma show, this will be a game-changer in conveyor drives design, it said. In this case, ABB is classifying "me- dium power" as being conveyors in the 3- to 10-MW drive class. By eliminating gearboxes, and using a permanent mag- net motor, ABB claims to have achieved more than 50% higher reliability and availability over previous designs, with more than 30% reduction in losses lead- ing to what it said are the lowest oper- ating costs available on a per-ton basis. Fewer components mean higher reliability with less maintenance needed, so equip- ment utilization rates are higher and pro- duction losses reduced, while the in- creased effi ciency gives lower specifi c energy consumption. In addition, noise generation is lower than with traditional conveyor drives. ABB explained that since convention- al low-speed synchronous motors cannot meet all of the requirements for the new drive in the medium power range, an al- terative type of motor was needed. The permanent magnet motor is light and compact yet capable of performing heavy duty in either foot- or shaft-mounted con- fi guration. Air or liquid cooling is used, with no external cooling circuits needed. The compact design means that it can be easily installed either from new or as a retrofi t option, with shaft mounting doing away with any need for alignment on site. The company gives the example of retrofi tting its new drives to an existing, 2-km-long belt conveyor travelling at 6.6 m/s and carrying 8,000 t/h. Gearboxes were eliminated without major structural reinforcement or modifi cation, giving a reduction in the total weight of the drive section, while the total mechanical and electrical effi ciency was increased from around 90% to 94%. The return on in- vestment was given as two years. Baldor's Motor-gearbox Packages Also part of the ABB group, Baldor's min- ing-sector products include its Reliance electric motors and Dodge reducers, fl uid couplings and bear- ings. The company provided E&MJ; with information about two conveyor pro- jects for which it re- cently supplied drive systems. At the fi rst, for a steam-coal company in western Kentucky, Baldor drives were used on a new ele- vated conveyor for moving raw coal from the mine to a barge loadout, and on off- loading conveyors at the prep plant some distance away. The design called for a total of ten Baldor Dodge MagnaGear reducers, coupled to Baldor Reliance mining industry motors. The company describes the MagnaGear XTR as being a high-horsepower speed reducer—a com- pact, power-dense design in a heavy-duty package. MagnaGear reducers are available in parallel shaft or right-angle confi gura- tions, with solid or hollow output shafts. They also come in several mounting con- fi gurations, including tunnel housings, with a universal housing design that helps users minimize spares stocks. Meanwhile, in Mexico, Baldor pro- vided Dodge Torque-Arm II reducers, S-2000 bearings and Mine Duty Extra pulleys, along with Reliance motors, for a series of 21 grasshopper conveyors used for ore stacking at a heap-leach gold mine. The mine also needed a drive capa- ble of providing a soft start for a heavily loaded belt, 575 m (1,890 ft) long with a 69-m (226-ft) lift. For this, Baldor sup- plied a Dodge 920 MagnaGear right-angle reducer and a custom 375-kW (500-hp) totally enclosed, fan-cooled Reliance mo- tor, with a Dodge fl uid coupling to provide the soft start. Turning to electric motors, Baldor's Crusher Duty motor line is engineered for use in high-torque applications and harsh environments in the aggregate, cement and mining industries. The range encom- passes 19 models offering outputs from 5 to 400 hp (3.7-298 kW), at base speeds of 900, 1,200 and 1,800 rpm. ABB's new gearless medium-power conveyor drive uses a permanent magnet motor with no gearbox. Baldor supplied Reliance motors and Dodge gear reducers to power 21 grasshopper conveyors at a Mexican gold mine.