PECM Issue 21 2016 | Page 5

installed into the stator of a machine much The process begins with more easily. an initial assessment of the components due for repair and Maintaining the quality of every coil is is followed by the design stage, a continuous process that is applied to which involves using the latest all aspects of the production process, 3D CAD packages to produce a including checks on all of the raw materials series of manufacturing drawings used in the manufacturing process. If there for the coil shop. Precision and are any perceived changes in the materials accuracy of the drawings, coupled with used in the insulation system, then a the latest insulation technology allows sample coil can be subjected, by customer for improvements in coil design to be request only, to voltage endurance testing achieved. Sulzer is the leading worldwide, independent service provider for large rotating equipment. With technically advanced and innovative service and maintenance support solutions, Sulzer provides a turnkey service that provides its customers with the peace of mind to focus on their core operations. www.sulzer.com in order to prove the insulation properties and reliability are unchanged. Suppliers have been known to change specifications of their materials without providing such information to the end users and so periodic sampling is also conducted to ensure the overall quality of the finished product is maintained. Precision and accuracy improve performance The use of B-stage resin rich coils is predominant in the rewinding of larger machines but this method also delivers benefits for smaller machines. The construction of the B-stage coils allows the resin to flow in the end of the winding and bond the layers of insulating tape to produce a more homogenous insulation and sealing of the winding. In most cases, the use of modern insulating materials will improve both the dielectric and thermal performance when compared to those used by the OEM during original manufacture. Quality starts with the raw materials and Sulzer purchases continuously cast copper rod and uses its own in-house rolling and annealing process, combined with automatic shaping machines and computer controlled heated presses. The entire process can operate 24 hours per day to deliver consistently high quality coils with very short delivery times. The coils can then be dispatched from its high-voltage coil shop, via freight service, to any location worldwide for delivery to site, ready for installation. By using the latest CAD software, the bars or coils can be precisely designed to ensure an exact fit in the stator can be required to pass a 400 hour voltage endurance test to provide evidence to support their build quality. slot, making the installation process Modern insulation technology allows for more efficient. Comprehensive testing thinner layers that can withstand greater techniques guarantee the reliability of the dielectric stress and higher temperatures, new coils, which is especially important also allowing more space for copper within for coils being used in marine, nuclear the same slot area. and hydro generators, where the coils Is sue 21 PECM 5