Coal Age

SEP 2018

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September 2018 31 drive systems continued Enabling "exact benchmarking," the GCD system "runs in parallel to the existing geared drive" on the 2.5-meter-wide belt "located at the end of the discharge boom," ABB reported. "Both drives connect to the same pulley shaft." The belt "moves sand" and "large rocks (ice-age foundlings) that give rise to mechanical shock and vibra- tion," the company reported. Ambient temperatures reportedly range from -25° to 40°C (-15°F to 104°F). And that is what the technology was built to han- dle, Richter said. "The drives are out in the field without any additional protection" from temperature swings, he said. Mobile or semimobile conveyors generate higher shock and vibration stress than stationary equipment, he said. And contaminant "in- gress must be avoided," Richter said. "This has all been incorporated in the design of the drive assembly." The results from Jänschwalde reveal the solution's wide applicability, he said. "The solution is designed to work in all mines." The individual GCD is designed for up to three megawatts (MW ) per motor, offer- ing up to 500 kilo-Newton-meters (kN-m) torque. A series of the drives can deliver between 5 MW to 20 MW, ABB reported. The permanent-magnet motors can be foot-mounted or shaft-mounted, the company reported. "The latter is quicker to install, easier to align and requires no concrete foundation work." The combo offers several benefits, the company reported. ABB described the GCDs as comprised of "fewer parts and new motor technolo- gy" increasing "the reliability and efficien- cy of the overall conveyor system." A GCD system, for example, "eliminates the gear- box from the drive." With fewer wear parts, less mainte- nance is required, and the lifespan is in- creased. "The expected lifespan for the drive train increases by more than 10 years, when compared to traditional geared sys- tems, to a projected in-service life of 25 years," ABB reported. The combo has a relatively compact footprint, which Richter described as "much" smaller than a conventional gear- less system with a synchronous motor. That allows a GCD system, with "less weight, and a reduction in the instrumentation required to operate the system," to "be in- stalled in smaller spaces," ABB reported. The primary benefit, however, is sav- ings, ABB reported. The aforementioned energy savings of between 6% and 8% contribute to overall cost savings, the company reported. "While the upfront investment is typically higher (by as much as 30%) when compared to a conventional drive, the savings in main- tenance, energy cost and downtime lead quickly to a return on investment of typical- ly less than one or two years," ABB reported. Then there are the intangibles that pres- ent as hidden savings. For example, Richter said, the GCD has lower operational noise levels. That pays off for mines located close to metropolitan areas with "strict noise lim- its to be met," he said. "The GCD reduces the noise emission of the drive drastically so that common noise-canceling housings around the drive are not needed," Richter said. "That may even lead to lower CAPEX." CAPEX can be further reduced by higher pulley speeds, which leads to lower motor torques, Richter said. "Considering the full scope of savings in OPEX and high- er production, ROI will be achieved after few years, and low production cost is guar- anteed," he said. With adoption, no additional infra- structure is needed for installation, com- pared to a conventional drive-motor com- bo, Richter said. For example, test facilities for managing the gearboxes are unneces- sary, he said. "The cooler module has to be included into the annual inspection of HVAC equipment," he said. "Inspection takes two hours per drive and year." When the savings are tallied, the solu- tion quickly pays for itself, Richter said. "With our confidence about that, we can offer financing options," he said. Other lessons taken from the pilot study will show up in future iterations of the solution, Richter said. "Based on lessons learned, we will improve dimensions of the cooler module and the motor by optimizing the design of the active part of the motor," he said. Those modifications "are planned and will be implemented with the next project." Increasing Intelligence Voith announced the impending launch of the Condition Monitoring System (CMS) 310, a torque-limiting coupling monitoring system. First showcased at MINExpo 2016, the solution was adopted in December 2017 for beta testing at one of the world's largest open-pit gold mines. Before the second quarter, the results were in and included data and testimonials that merit banging "on the big drums this time," said Håkan Westberg, product management head, torque limiting and connecting couplings, Voith. The CMS 310 consists of sensors mounted on the torque-limiting coupling (TLC) and a computer-based monitoring system, Voith reported. Hardware includes small sensors, connecting wires and a 20- cm by 20-cm PLC box. The interface is ei- ther an HMI panel or a web portal. The system is promoted as an add-on or upgrade to any of the company's line of hy- draulically pressurized, friction-based TLCs, the SafeSet, SmartSet, SlipSet and AutoSet. The need for the CMS arose from the common phenomenon of "nuisance" trips causing machine downtime, West- berg said. "That is momentary machine overloads without full blockage," he said. Such overloads might do nothing or they might damage the drivetrain. Either way, the resulting automatic machine shut- down might cause machine downtime. "Hence, we started developing SmartSet and SlipSet slip-enabled TLC," Westberg said. "And we wanted to have a system to provide feedback to the operator." For example, "the SafeSet TLC imme- diately releases when the set torque has been exceeded," which, the company re- ported, "allows your driveline to operate at the maximum level" without exceeding the machine's design capacity. Westberg described the SmartSet and SlipSet TLCs as containing two specially coated friction sleeves that are engaged with applied hydraulic pressure. The TLC is "like a mechanical fuse," Voith report- ed. "In an overload situation, when the set torque is exceeded, the SafeSet releases" the hydraulic pressure instantly and freely rotates on internal bearings transmitting no torque through the driveline, saving it "from catastrophic failure." That design keeps the machine hum- ming along after nuisance, short duration, torque peaks that otherwise might have caused a shutdown. And in a truly anoma- lous torque spike, it effectively shields the drivetrain. Add on the CMS 310 and a user can monitor the TLC remotely. "Slip angle is

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