LH Marthinusen (LHM), a division of ACTOM (Pty) Ltd, isa leading repairer of transformers and large rotating machines and manufacturer of specialised transformers, recently completed a contract for the manufacture of 16 new 500kW DC traction motors to replace existing motors for diesel electric locomotives.
“The original motors for the Model 7E locomotives owned and operated by a major rail company had to be replaced by new ones as they were approaching the end of their lives, having been in service since the 1960’s,” commented Boris Breganski, LHM’s Operations Manager, Power Generation.
Little information on the original motors was available, resulting in LHM having to conduct a reverse engineering process on one of the existing motors to establish all the dimensions and design elements to enable manufacture of the new units.
“In order to engineer the product a three-dimensional laser scan was undertaken of a sample rotating machine. From the scanned data the engineering model and manufacturing drawings were drafted. The engineering drawings were then verified using a boring mill’s electronic dimensional read-out,” Breganski explained.
The manufacturing design was verified using finite element analysis (FEA) modelling techniques, ensuring conformity of the final manufactured product.
A thorough quality control programme of the manufacturing programme was implemented, which included the suppliers of various outsourced components. Testing procedures were implemented for all stages of the manufacturing programme to ensure the required tolerances were achieved.
Finally the completed traction machines were dynamically tested utilising a back-to-back full-load configuration.