Compact, Contained and Cooled
In a collaborative effort, Rockwell Automation and the AGL Loy Yang engineering team developed a new drive solution, founded on the Allen-Bradley PowerFlex 7000 medium voltage (MV) AC drive. Featuring ‘Direct-to-Drive™' technology – a technology that helps eliminate the need for isolation transformers on applications with either new or existing motors – the Allen-Bradley PowerFlex 7000 MV AC drive provides space-efficient speed and torque control across a range of demanding drive applications.
The mine engineering team came up with an idea to equip each conveyor with a fully self-contained, cooled and removable drive package that could be easily installed or uninstalled on any of the mine's conveyors. This provides AGL Loy Yang with a level of portability that improves production flexibility.
According to Rockwell Automation engineering team leader, John Dunn, the compact nature of the PowerFlex 7000 drive simplified the development of the portable drive packages.
"The transformerless configuration of the PowerFlex 7000 meant we were able to help minimise the footprint of the drive package," he says. “The main electrical feature is the load sharing between different drives on each conveyor. We developed a partitioned stainless steel IP65-rated enclosure, equipped with an air-conditioned cooling system, to house each of the 6.6kV PowerFlex drives.”
The ‘minimal component count' was also a feature of the PowerFlex drive solution, with fewer parts eliminating the number of things that could go wrong.
Nine drive packages have been supplied to the Loy Yang Mine site to date. One of the main challenges throughout the upgrade has been integrating Rockwell Automation drive technology with the mine's existing drive technology and control architecture. The first PowerFlex 7000 drive packages interfaced with a PLC5 systems package in the neighbouring switchroom.
ControlLogix® is, in turn, linked to the mine's supervisory control and data acquisition (SCADA) system, via the mine's existing communications network. Each drive package is equipped with an Allen-Bradley electronic operator interface (EOI) located on the front panel of the drive enclosure.
“The drives can be interrogated via these EOIs or through the mine's SCADA system,” says Dunn. “The locally mounted EOIs make it easier for site personnel to access drive diagnostics without opening the dust-proof enclosures and exposing the drives to the elements.”
The Rockwell Automation and AGL Loy Yang engineering team developed a strategy that allowed the new drive packages to seamlessly synchronise with the existing ECC drives.
“Our long standing relationship with Rockwell Automation means integrating new drives at the mine has become a relatively straightforward project to complete. We have a lot of experience using the drives now, making it a fairly easy, run of the mill upgrade that doesn't take too long,” said Collins.
Proven Working Relationship
According to Dunn, “There were key benefits to the level of integration and flexibility achieved at the mine from being involved in this project from its inception and design phase, through to supply and installation.”
However, with upgrades at Loy Yang Mine continuing, there is much work ahead. The AGL Loy Yang team is planning to progressively replace other ECC drives across the mine. “When the first project with Rockwell Automation happened it was very significant for the mine, but our ongoing working relationship means that the drives have become very seamless to integrate,” says Collins.
AGL Loy Yang is currently in the process of constructing a new conveyor using PowerFlex drives inside a new switch room. Additionally, the engineering team is designing a new downhill conveyor based on the Rockwell Automation drive solution that will be used for backfilling the mine.