CHI Control Components marketing director Rob Hare explains that the platinum smelter has three electrodes, each of which are driven by a 30-kW electric motor and is controlled by a Vacon NXP variable speed drive, which uses closed-loop vector control.
He adds that the smelter's electrodes would each strike a different arc, and the current feedback would be used to to control the forward or reverse direction of the motors for each electrode.
Significant to this application, is the fact that the positioning and control of the electrode is done by means of an electrical brake control inside the drive. Speed control is achieved between 0 Hz and the set speed, without having to use the mechanical brake control during the operation, while the mechanical brake is only energised in an emergency or fault condition.
The complete control of the electrode hoist uses the Devicenet fieldbus system to do the control, in conjunction with the special multi-purpose application software present the variable speed drive.
By means of encoder feedback, the company has an understanding and knowledge of the specific position and movement of the electrodes.
Hare adds that this specific software is ideal for applications such as winders, hoists and master slave.
Besides this application, CHI Control Components now also offers a Profibus module known as the Profibus Starter Network Adapter (PSNAP), which has been engineered, designed and manufactured locally.
The PSNAP module is connected to the information technology (IT) starter product range, sourced from diversified industrial manufacturer Eaton Corporation, which offers a complete product range at a competitive price.
"When developing the PSNAP, CHI Control Components focused on the IT starter, owing to it comprising a contactor section, as well as a motor protection unit with electronic control and current measurement circuit sensors," he says.
By means of the Profibus master, a module can also be configured to gain access to different motor control data and status. The company therefore decided to allow the PSNAP module to function as an auto controller through the Profibus, and as a manual controller of the motor starter.
In addition, the module has a fault and operation indication, which allows for light-emitting diodes indicating the hardwired signals, module status, fault conditions raised, Profibus node address indication, as well as network status indication by means of dedicated indicators.
The PSNAP module can also function as a dumb input/output unit, adds Hare.
CHI Control Components' range of products is readily available throughout sub-Saharan Africa through a network of branches and over 40 distributors.