Coal Age

MAY 2019

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16 May 2019 crushing systems Rigging Crushers to Reduce Downtime Drive system solutions are designed to protect equipment when processing rocky coal by jesse morton, technical writer Plug-and-play solutions are popu- lar right now across the coal space. A couple of those technologies that are advertised as simple to install, operate and maintain are said to cut costs by protecting crushing systems that pro- cess rocky seams. Both can be adopted by either original equipment manufac- turers (OEMs) or miners in the market for a new crusher, or can be integrated into a legacy system as a retrofit. Nei- ther are inexpensive, but both promise solid cost savings in the long run. Drives for Feeder Breakers Saminco International Inc. reported a unit from its recently released JR1000 line of 1,000-volt (AC) variable fre- quency drives was adopted by a proj- ect run by one of America's biggest coal mining companies. The miner adopted the drive as the key component to a feeder breaker system designed to nix downtime and protect a crusher from tramp rock. Either the 110-kilowatt (kW ) VF1001, as a single inverter, or the 220-kW VF1002, as a regenerative rec- tifier, both capable of "infinitely vari- able speed tramming," can be built into a feeder breaker system, Samin- co reported. For example, the VF1001 can be configured "to control the conveyor motor on the feeder breaker," Lane Cerise, sales and service engineer, Saminco, said. "There is a CT that hooks into this through a smart box that is load sensing the crusher. As the crusher gets a higher amp load on it, when something is too hard, this drive will sense it and automatically slow the conveyor down and feed the material through slower, so you don't break anything." Company literature described the capability as taking "cutter motor feedback to optimize tram speed." A similar capability is described as "energy-saving regenerative braking down to stall, which can be held in- definitely without inverter or motor overheating." Certain modes of op- eration offer "unsurpassed accuracy to allow low speed holding when de- scending," especially when triggered by a proximity detection system. Thus, the line offers "full motor protection" from overload, short cir- cuits, locked rotors, jams, ground faults and more, Saminco reported. The solution was originally devel- oped for a continuous miner system. "It was designed so you don't have to have all the transformers," Cerise said. "With it, the customer doesn't have to have different levels of power distri- bution," he said. "It is just a straight feed, a lot more efficient, and a lot lower energy use by using 1,000 volts." Both the VF1001 and the VF1002 are rated for an AC input of between 855 and 1,254 volts. Output for the former ranges from 0% up to 95% of that input. For the latter, the DC out- put is 135% of the AC input. The VF1001 is a diminutive 48 by 37 by 20 cm and weighs 55 kg. The VF1002 is 12% smaller in size, but weighs 65 kg. Control systems can be analog or CAN Bus-based. "Radio-controlled" operability is available, the company reported. The primary benefits include less maintenance of crushers or convey- ors and less downtime. "You are not fixing things all the time because of big rocks going through there break- ing things," Cerise said. In the old days, shear pins were used to prevent tramp rock from being fed to a crusher. "It would get a load and just bust pins," Cerise said. "And while they were trying to get all the pins back in, the coal section is down." The 110-kW VF1001, left, is rated for output of up to roughly 1,250 volts AC. The 2200-kW VF1002 is a regenerative rectifier for crusher feeder breaker systems where DC is required. (Photo: Saminco)

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