The "Boring" Service Call:  or, the story of Rocky and Rocksanne

The public became aware of the existence of large boring machines, after the publicity surrounding the two that were used to drill the "Chunnel" under the English Channel.  (Incidentally, they are still buried under there, it being cost prohibitive to get them out. )

What's less known are that these same types of machines are at work all over the world, including right here in Atlanta, Georgia.  The boring machines are powered by electronic motor drives, and as the nation's premier drive service company, naturally EMA is involved.

 Atlanta's mayor,  Shirley Franklin christened one of the giant machines,  named "Rocky" in June of last year.    The project, known as the Combined Sewer Overflow tunnels, or CSO, will be constructed by using two boring machines.  Mayor Franklin took great delight in pointing out that the 'female' machine, named "Rocksanne" will be doing the largest portion of the work.  The petite Ms Franklin, and her companions, were dwarfed by the giant Rocky's cutting blade.   The tunnels are 8.5 miles long, and 24 feet in diameter.  The machines are manufactured by Herrenknecht AG, of Germany.  The electric motor drives to power both machines are manufactured by VaTech of Austria.   EMA is the only authorized VaTech service center in North America. 

A few weeks ago, EMA Georgia  Manager Abdou Barrow, and engineer Eric Nguyen, responded to an emergency call from VaTech to the CSO project.   As you might imagine, the control scheme for these machines is complex, consisting of drives, logic controllers, and a human machine interface. 

 To get to the machine, Eric and Abdou traveled down a 300 foot vertical drop entry shaft,  and then traveled about a mile into the tunnel.  Once there, they found a connection that had vibrated loose, and caused an IGBT to fault on one of the 300 HP drives.  (There are six of these on each machine).  After repairing it,  they tuned the drive for improved performance, and the tunnel construction restarted.   As you can imagine, downtime is critical in these applications, and the crew was very pleased with the quickness of the repair.   

 VaTech also supplies drives for large extruders, and other applications.   EMA enjoys a wonderful relationship with VaTech, and we find them to be not only excellent technically, but very customer oriented. EMA has traveled all over North America on behalf of VaTech.

Eddie Mayfield
EMA Drive Lines, January 2007

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