Marthinusen & Coutts (M&C), a division of ACTOM (Pty) Ltd, is BEE accredited and offers full on- and off-site electromechanical services and repairs of power generation equipment, medium and low voltage AC and DC motors, transformers, and coil manufacture, as well as the full range of engineering, testing, diagnostics, balancing, and maintenance services.
July 2024 saw M&C complete a one-year project for Sasol to rewind a 75MVA BBC synchronous generator stator. According to Dominik Krob, Project Manager at M&C, “This type of generator, especially the generator windings, eventually reaches the end of life and needs to be rewound, which is where we come in.
So instead of replacing the entire machine with a new one, the customer decided to rewind this particular stator.”
This generator is a critical component of a SASOL’s power generation system.
“There are several industrial manufacturing plants in South Africa, and the manufacturing industry has suffered severe losses during the load shedding period in our country. So, many of these manufacturers generate their power in-house to be independent of the grid”, Krob added.
With M&C having close working relations with crucial parts suppliers, National Electric Coil, based in the United States, was the likely partner to assist in achieving the tight deadlines on this project.
NEC developed a unique system with individually Vacuum-Pressure-Impregnated (VPI) stator bars and coils, individually wrapped with the NECCOBond-ETMproven insulation system, and meeting every National and International Standard.
Complexity
While there are numerous stator bar and coil suppliers globally, their quality is not guaranteed. Furthermore, quality issues often reveal themselves only after several years of operation, when it is too late to change suppliers or even claim damages from them.
NEC is one of the very few suppliers that can manufacture individually VPI-stator bars world wide, and it has been doing so for decades, making it a very reliable and trustworthy technical choice.
Testing
M&C has its own testing capabilities in their factory, but this stator size requires exceptional (expensive and large) test equipment to perform the optimum tests and guarantee product quality.
For this purpose, M&C has partnerships with specialist local high-voltage test equipment service providers.
The HV Test and their 50kV resonant high-voltage test set are among them.