Published: May 12, 2010 |

OPTIDRIVE equipped feeder-breakers are available for both underground and surface applications.

[Click image to enlarge]

[Click image to enlarge]

Few innovations in mining machinery technology have been as widely adopted and enthusiastically accepted as has Joy Mining Machinery’s OPTIDRIVE AC variable frequency drive. In less than two decades, OPTIDRIVE has grown from inception to being universally applied to Joy’s underground mining equipment, most recently as an option on the company’s STAMLER PRODUCTS of Feeder-Breakers.

“There have been variable frequency drives (VFDs) on feeder-breakers for a number of years,” offered Mike Chizmar, Global Product Manager Feeder-Breakers, “but nothing to compare with the advanced integrated capabilities Joy’s OPTIDRIVE brings.

“Additionally, with OPTIDRIVE our customers have a single interchangeable drive control system for JOY underground mining machines: Shuttle cars, continuous miners, flexible conveyor trains and, now, feeder-breakers,” he said, noting that each piece of equipment still retains the software unique to its application.

What OPTIDRIVE does is integrate the electrical and mechanical systems and each unique piece of software. Where the motors and drive in the OPTIDRIVE system are designed for each other, Joy controls the technology to ensure a compatible system that maximizes utilization of both components, as opposed to using industrial off-the-shelf components modified for underground mining.

OPTIDRIVE equipped feeder-breakers are available for both underground and surface applications. Interest in VFD with underground feeder-breakers is on the increase and, currently, about 60 percent of the units going into surface applications are so equipped. All STAMLER Feeder-Breakers with electro-mechanical conveyors are capable of accepting VFDs.

Worldwide, more than 1,000 STAMLER Feeder-Breakers are currently in use making Joy the market leader for feeder-breakers in both the U.S. and globally.

The origin of OPTIDRIVE dates back to 1992 when Joy adapted AC variable frequency drives to two existing continuous miners, with redesign and retrofitting following in 1996 and 1997, the same year when Joy installed a similar VFD on a longwall shearing machine; the same basic unit in use today, upgraded along the way to improve and increase overall performance.

The major advantage of AC drives is that more power can be provided to drive a machine within the same space previously occupied by DC motors. Additionally, because AC motors are brushless, the time-consuming and maintenance expense of brush replacement associated with DC motors is eliminated, as is the possibility of contaminants entering the motor during replacement.

In 2001, the next generation VFD system was fitted to continuous miners and, two years later, to Joy’s flexible conveyor train (FCT) continuous haulage system and shuttle cars. By 2004, Joy introduced OPTIDRIVE, the bringing together of the interchangeable hardware and the software unique to each machine under a single brand name.

“Since then,” Chizmar noted, “its success has been exceptional and the reason for this unparalleled success is OPTIDRIVE’s proven increased performance, reliability and availability. In addition to offering the universal benefits of interchangeable parts and reduced inventories, reduced maintenance costs and lower costs per ton of coal mined, OPTIDRIVE also brings individual benefits to each piece of equipment, such as increased longwall shearer motor capacities and new software that provides increased current limit of the drive at slower motor speeds, improving both performance and reliability.

“With shuttle cars,” he continued, “OPTIDRIVE resulted in a significant increase in power, speed and productivity, as well as in improved operator comfort that in itself promotes productivity. With continuous miners, this gave Joy the ability to design physically smaller machines for low seams without sacrificing the power and mass essential to mining the coal in the most productive and efficient way possible. Also, OPTIDRIVE made it possible to increase the maximum tramming speed of the continuous miner to more than 85 feet per minute (25 metres per minute) and, in the instance of the JOY 14CM27 continuous miner, to 90 feet per minute (27 metres per minute). This means less time moving place-to-place and more time doing what a continuous miner is designed to do, mine coal.”

The key to the effectiveness of the identical OPTIDRIVE hardware and machine-specific software is no better demonstrated than in its application to Joy’s flexible conveyor train. OPTIDRIVE matches the speed of the traction and belt systems between the outby and inby ends of the machine, enabling the operator to tailor the belt speed to match the production rate of the continuous miner. This helps reduce belt wear that, together with the system’s soft-start capability, results in longer belt life and lower costs per ton of coal mined.

“This is similar to what OPTIDRIVE brings to STAMLER Feeder-Breakers,” Chizmar noted. “While the function of the feeder-breaker is the same regardless of application—to break/size material, to convey it and discharge it—its final design may not be as we take into consideration the hardness of the material to be processed and the potential detrimental effects, if any, on the conveyor related components. Other design concerns include customer preferences and associated maintenance.”

According to Joy, the OPTIDRIVE system programming controls the conveyor by two means. Either the conveyor speed can be varied manually through the VFD or the breaker motor amperage readings can slow the conveyor automatically to facilitate breaking of the material being conveyed to the discharge end of the unit. Prior to OPTIDRIVE, with electro-mechanical conveyors the only way this could be accomplished would be to physically install retarding chains or to change sprockets or electric motor RPM, neither of which is really feasible unless the change is to be permanent.

OPTIDRIVE allows an operator to control 25 percent to 100 percent of the feeder-breakers rated conveyor throughput capacity, which is particularly important in handling hard materials. By slowing down the flow of material through the breaker, there is less impact and shock load on the breaker components, prolonging life and reducing maintenance. In one instance, in converting from an electro-mechanical conveyor machine to an OPTIDRIVE AC-VFD unit, an operator reported reducing the number of shear pin failures by more than 50 percent.

“With OPTIDRIVE,” Chizmar continued, “these advantages are accomplished with less hydraulic circuits while requiring less than typical hydraulic maintenance. When you can increase efficiency, decrease wear, decrease maintenance and the time it takes to perform it, you allow the operator to spend more time in the coal. When you do that, you have made a major contribution to lowering costs per ton, improving production and productivity, and increasing profitability.”

For more information:
Contact: Lou Boltik, Director Marketing Communications
E-mail: .(JavaScript must be enabled to view this email address)

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