A Pioneering Step

In an innovative ‘first’ to keep a customer’s mining project in the Democratic Republic of Congo (DRC) on schedule despite the impact of Covid-19, Zest

WEG successfully conducted a remote witness test of Medium Voltage (MV) Variable Speed Drives (VSDs) in WEG’s Brazil factory. “These are extraordinary times, and require extraordinary measures,” says David Spohr, business development executive for high-voltage equipment at South African-based Zest WEG. “With the restrictions on international travel, we had to think creatively about how to complete this final step in the manufacturing process, the witnessed Factory Acceptance Test (FAT), before the equipment could be shipped to the DRC site.”

Under normal circumstances, these tests would require the customer to travel to Brazil and spend a week at the factory witnessing and signing off a range of detailed test and equipment requirement

Under normal circumstances, these tests would require the customer to travel to Brazil and spend a week at the factory witnessing and signing off a range of detailed test and equipment requirements. This order comprised two 7MW 3300V WEG MVW01 VSDs for the ball and SAG mill drive application and two 1,2MW 3300V WEG MVW01 VSDs for the HPGR mill application. Both applications required non-standard features, namely ‘frozen charge protection’ software on the ball and SAG mill application and a ‘master & follower’ configuration on the HPGR mill application.

A view of the testing facilities at WEG Brazil David Spohr, business development executive

Participatory

“It was essential that we did not delay the customer’s project, so we arranged to conduct the witness test using web-based communication software,” says David. “This allowed the participation of Zest WEG experts, the engineering contractor and the end-user, all from the safety of their homes in Johannesburg while communicating with five testing technicians in the WEG factory in Brazil.” Using a high-definition camera and web-based communication software, the factory technicians were able to walk the contractor and end-user through each element of the FAT, with clear and real-time visual images of the test results and equipment on the factory floor. The tests continued for three days, beginning at 13h00 and ending at 19h00 to account for time zone differences. Testing covered three key areas – PLC communication software integration, full functional testing and full load testing.

Way of the future

“As with any other witnessed FAT, the customer was provided with a comprehensive results report by WEG. This enabled the customer to check, in exactly the same way, that the remote FAT results were within the required tolerances.” David notes that this pioneering step is likely to influence the way that these tests are conducted in future. “It has shown that the testing can be carried out to the same standards, but with significant savings in time and cost,” he concludes. Zest WEG Group www.zestweg.com