Drives replace DC servo control at Cosworth

DC servo control systems on a pick and place gantry used in the Cosworth Technology casting operation in Worcester have been replaced by AC geared motors and smd micro drives from Lenze.

DC servo control systems on a pick and place gantry used in the Cosworth Technology casting operation in Worcester have been replaced by AC geared motors and smd micro drives from Lenze.

The decision to ditch the "higher" technology DC system was taken by Maintenance Manager Joe Reeves based on cost and performance, the original system having been deemed overcomplicated and costly to replace like-for-like when compared to the levels of accuracy and ease of integration offered by the new generation of small AC drives.

Cosworth Technology produces high quality aluminium alloy castings predominantly for the automotive industry, complementing the powertrain and diagnostic engineering services provided by the company.

The casting facilities at Worcester are flexible enough to make three or 300,000 items per year of any design using the patented Cosworth Technology casting process.

Central to the casting operation is the accurate and reliable transfer of crucibles containing molten aluminium from the furnace to the moulds.

The working environment is tough, with a sometimes heavy workload and 50C heat, and so the replacement system had to be tough as well as reliable.

The original system had reached the end of its operating life and was due for replacement.

Advances in power handling and reduction in size (a 2.2kW smd inverter has a panel size of just 146 x 114 x 140mm) meant that four smd drives would fit comfortably into the existing control cabinet, and the units offered levels of accuracy and reliability that were not easily achieved with AC control when the original system was specified.

The cost differential between a new replacement servo system and the AC solution using standard Lenze geared motors, derated to handle the high ambient temperature, is an order of magnitude lower, reducing both the initial purchase cost and limiting the cost of any future replacements.

Ease of control was also a factor in the selection, Glyn Fisher, the Lenze Sales Engineer who specified the gearmotors and 2.2kW smd drives: "The setup takes a few minutes on a laptop with a simple to use Windows based software application which means the user is perfectly able to set the drive up and can fine tune it from the PC or on the drive itself.

Even if the drive needs resetting or replacing, the program is held on a removable chip that can be transferred in seconds.

The parameters can be copied to a spare chip and kept just in case.

The result is a fast setup, good flexibility and downtime kept to an absolute minimum".

Joe Reeves, Cosworth Technology Casting Maintenance Manager comments: "It makes perfect sense to use a simpler technology for this application; not only on the cost advantages, but it makes any changes for operational and the maintenance reasons faster and less of a headache.

Controlling the crucible gantry is central to the operation because we run a highly flexible casting system in order to handle what might be a very short run of bespoke engine parts or long runs for road cars such as Aston Martin for example".

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