The latest in scoop, shuttle car technology

By Donna Schmidt, Field Editor

Scoops and shuttle cars, without a doubt, are the workhorses of any continuous operation, and as such they naturally are a source of endless scrutinizing by operators and original equipment manufacturers (OEMs) alike. Both are always looking for the all-in solution to provide higher and more efficient production, safer operation, reduced emission, decreased maintenance, consumables replacement and more.

Improvements are being made at the research and development tables and are being brought into design in many of these areas. Even better, nearly all of the industry’s major players have been working diligently over the last few years to keep this technology quite literally at the cutting edge.

The aftermarket and rebuild segment of this area is also getting plenty of customer feedback on needed improvements, and the vendor arena is listening carefully. Below are a few examples of this work put into action.

New AC conveyor motors from Joy utilize the same mechanical package as the existing conveyor motors.New AC conveyor motors from Joy utilize the same mechanical package as the existing conveyor motors.

 
Pursuing the Lowest Cost per Ton

The concentration for Wisconsin-based Joy Global as of late has been on continuing its lowest-cost-per-ton mission, and in the area of its scoops and shuttle cars, that focus has been two-fold and related to hardware. The first is the 550V DC, its variable frequency drive (VFD)-conveyor system is designed to help match up the discharge rate of the shuttle car to the belt infrastructure on which the tonnage is being loaded.

“The VFD pump allows for the trailing cable to come under tension at a slow controlled rate when the pump is initially energized,” the company said. “This, in turn, reduces the strain on the trailing cable as it eliminates the initial whipping of the cable when it comes under tension.”

 

This Joy motor design, which is permissible, does not require encoders, as the Joy motors are matched and “tuned” to the VFD drive. Additionally, the Joy system requires just two drives to run all four VFD motors.

Because there are fewer components loaded into the system, it is easier to troubleshoot, resulting in reduced downtime, and the DC VFD’s drive enclosures are internally cooled.

According to Joy officials, its current proven AC VFD drive units have been redesigned to accept a 550-VDC input, which permits DC voltage to be supplied directly, eliminating the need for any DC rectification internal to the drive unit. Moreover, relocating the DC rectification off the machine allows for a second motor output without increasing the drive unit package size.

“That DC voltage is then converted into a variable frequency AC output voltage between 5 Hz through 90 Hz; this is the same as in the current proven AC VFD drive units,” the OEM said.

Joy Global is also spotlighting the globally approved OptiDrive system for shuttle car conveyors, which increases conveyor system and component availability and reliability by reducing the shock loading to all key parts of the conveyor drive. A new AC-conveyor motor utilizes the same mechanical package as the existing conveyor motor. Motors are mechanically the same as the non-VFD motors, and the new designs have been based off of proven Joy conveyors already in use.

The OEM also said that the windings have been redesigned to optimize the VFD outputs, and there is now a single conveyor motor part number for voltages and frequencies, making life easier for mines’ maintenance staff.