A 125 tonne crane, using a 100kW motor, is used to help service stone crushing equipment operating in the massive South African open cast mine that covers over 375km2. The crane is required when the Stone Crusher becomes blocked or requires maintenance and with this Crusher being a Primary Crusher, reliable performance in this is of paramount importance, especially under such demanding operating conditions
The 132kW Optidrive Plus 3GV specified for this application has exceeded all of the demanding performance requirements. With this new variable speed drive in place the crane was able to operate with supremely smooth speed control for guiding bearings back into place in the stone crushers. With clearances down to as little as 20mm when replacing these bearings and any damage being extremely costly to repair, precise control is an absolute necessity.
Optidrive Plus 3GV was able to achieve this stunning performance thanks to a revolutionary, patented motor control strategy that delivers 200% torque down to 0.0Hz. This allows unique open loop control without the need for any feedback device in many traditional closed loop applications. Only the motor name plate data is required to achieve optimum performance, the drive continuously and automatically determines and tracks the key motor characteristics required for vector control.
Invertek South Africa Director, Mark De Beer, confirmed: "The Optidrive Plus 3GV has now been established for several years as a market leading variable speed drive for applications with power outputs up to 160KW. At the top of the list of competitive advantages offered by the Optidrive Plus 3GVis its outstanding torque performance. Optidrive Plus 3GV has proven time and time again to provide more torque at low speed than other competitors products"
Mark continues: "Up to 200% starting torque means the drive can carry out the most arduous applications without an expensive and fragile encoder. In addition, because the torque can be controlled or limited, the need for mechanical torque limiting devices is eliminated in many applications and substancial savings on often expensive maintenance costs can easily be achieved due to shock loading being completely eliminated"
The issue that is often overlooked is that the low cost, maintenance free electronics replace expensive, maintenance prone mechanical devices - providing significant cost and maintenance benefits
Optidrive Plus 3GV can be commissioned using the unique Optiwand PDA software designed for use on pocket pcs. Communication takes place without wires using infrared light to quickly and accurately transfer data.