Mining Transformer Offers Superior Performance

Becker/SMC’s mining-class-certified power distribution system solutions help companies improve safety, productivity, and conformity to plan

By Jesse Morton, Technical Writer

Becker/SMC reported the Duratrans dry-type transformer is designed for mining applications, which makes them superior to competitor solutions that are not mining class. “Traditional manufacturers use out-of-date winding techniques and technology for the most critical power-delivering part of your equipment,” said Justin Tidd, chief sales officer, Becker Global.

“The Duratrans transformer is intended to address the challenges specific to dry-type applications,” he said. “These challenges are met by producing a wound transformer coil that results in a mechanically robust construction preventing winding displacement and sealing out all environment contaminants.”

Compared to the traditional dry-type transformer, the Duratrans “has an improved performance of 15% at full load temperature rise at similar watts per square inch of cooling surface,” Tidd said. “This improvement demonstrates the transformer’s superior ability to handle thermal shocks from sudden peak overloads and cyclic loading, making it ideal for rectifier, variable frequency drives, and harsh environments.”

The transformers are certified to the specifications of ANSI C57.12.9. The design was put through a testing process that included “dropping it from over 12 ft onto concrete, slamming it with sledgehammers, putting a blow torch onto the coils, and spraying the coils with water before retesting its performance,” he said.

Becker/SMC also reported it has delivered 11 50-ton Electric Houses (E-Houses), each of which can control a 2,000-hp drive. Field results show the solutions operate “with zero quality issues and 100% uptime,” Tidd said.

For surface mining, the company also supplies substations, vacuum circuit breaker switch houses, rabbit boxes and more. “Becker/SMC provides the complete electrical system up to 35 kV, with various secondary voltages,” Tidd said. “We understand what it takes to keep a surface operation on schedule and in production with the electrical requirements needed.”

It also rebuilds much of the same solutions. “We not only rebuild our own equipment, but also other manufacturers’ equipment,” Tidd said.

“Rebuild projects include the complete overhaul to bring life back to the equipment to an as-new look and operation, or basic clean sweep, test, and paint to ensure the equipment meets the customer’s needs,” he said. “We can handle everything from switch houses, mine power centers, explosion-proof equipment, mobile substations, to longwall electrical control systems.”

Arc Guard for UG Power Centers

Separately, Becker/SMC reported in-house and third-party certification testing proves Arc Guard delivers a superior performance at containing an arc flash and blast. “This solution projects our company mission to be the safest, most efficient, and most technologically advanced mine power distribution company in the world,” Tidd said.

Arc Guard offers several benefits to American miners, including reduced costs and increased safety. It is designed to contain what may be the most dangerous electrical event possible in an underground mine.

An internal arcing fault is typically caused by insulation degradation or contamination, or water or foreign object ingress to the energized bus, which creates an electrical discharge path through the air. “During an arcing fault, the voltage at the fault location is essentially the system voltage, and the fault energy is focused within the equipment,” Tidd said.

“Arc temperatures can exceed 35,000°, rapidly heating the air, vaporizing metal parts and creating thousands of pounds of impact force,” he said. “The expanding plasma creates severe mechanical and thermal stress in the equipment, which can blow off top covers and panels, open doors and burn through the enclosure.”

An arc flash is fatal at distances up to 10 ft. Arc flashes send more than 2,000 people per year to burn centers, Tidd said.

“These tremendous temperatures can vaporize metal, resulting in pressure waves that can rupture eardrums and collapse a person’s lungs,” he said. “Shrapnel expelled from an arc flash can exceed speeds of 700 mph, fast enough to completely penetrate the human body.”

The Arc Guard is designed to withstand such forces until a power circuit breaker cuts the electricity to the fault. “This capability is verified by short-circuit and short-time withstand tests on the equipment and interruption tests on the power circuit breakers,” Tidd said.

“During a bolted fault, the voltage at the fault location is essentially zero and the fault energy is dissipated throughout the power system,” he said. “The arc generated within the power circuit breaker during interruption is cooled and extinguished by the breaker.”

Off-gassing of byproducts is trapped in the electrical equipment, which has been proven in interruption tests. “The Arc Guard technology wasn’t only tested at Becker/SMC’s facility, but also by the ANSI/IEEE C37.20.7 internal arc classification testing process on performance by a third party testing facility,” he said. “Which has proven the unit provides protection from hazards of internal arcing faults.”

Arc Guard is rated Class 2B, and protects miners at the front, back, and sides of the equipment. It features a reinforced enclosure, an internal venting system with pressure dams and pressure vents to channel the flow of fault gases, and reinforced sealed top covers and panels.

Made in the U.S.A., relatively short lead times on orders are routine. “Everyone feels the effects of the trending supply chain disruptions,” Tidd said. “However, Becker/SMC is a complete OEM that also manufactures the sub-assemblies of mine power equipment, which allows us to control our quality and delivery without having to depend on other suppliers.”

Stories and testimony from customers show the capabilities of the solution. For example, a couple years ago a mine “had an issue with a CPT, which created an arc flash within the enclosure,” Tidd said.

“Arc Guard did its job, no one was injured, however the next benefit received was, as the unit contained the arc flash to one compartment, the client was able to change out the CPT and high voltage wiring in four hours, putting the same unit back into production quickly,” Tidd said. “A traditional mine power center would have been beyond economical repair.”

Another customer also said the solution, by protecting equipment, reduces repair costs and time. “Underground mining is a demanding application for all equipment, and the environment requires a robust design to provide a product for a long safe life,” said Keith Hainer, president, Allegheny Metallurgical.

“Arc Guard is an evolution in power equipment design that will increase the useful life span and safety of the units,” he said. “The investment in the Arc Guard system will result in a reduced hazard to mine personnel and a quicker repair time at less cost than tradition power equipment when an arc flash event occurs.”

Reduced damage and repair time means a quicker return to normal productivity.

“The Arc Guard solution reduces the chances of physical damage inside and outside of the equipment during an arc flash event as it routes hot gases and forces to designed escape points,” Hainer said. “Reduction of the physical damage means mine personnel are safer, and productivity can be more quickly restored.”

By helping limit disruptions to processes and productivity, Arc Guard can help a miner execute a business plan, which is imperative to stakeholders. “The Arc Guard system will provide a more stable mine system,” Hainer said. “From an investor’s view, this stability means the mine produces as designed to support the business plan, and this is what all investors want.”

Arc flash protection for power centers is relatively new to mining. Gradual changes in the industry sparked the demand for it, Tidd said. “Motors are only getting larger and current is greater than ever before, leaving standard mine power centers vulnerable to arc flash situations.”

In 2010, the supplier launched a project to develop an arc flash protection solution. “Arc Guard was born and has been implemented worldwide,” Tidd said.

The advent of the solution and its subsequent noteworthy success showed the company’s dedication to its customers. Since its founding in 1971, “Becker/SMC focused on quality products and service to meet customers’ needs,” Tidd said.

“We are the industry’s leader in increasingly more sophisticated electrical control systems,” he said. “Most of the major innovations in the industry, design features, and specialized electrical components have been developed by Becker/SMC.”