2010 Award Winners
Award-winning project: Innovative bending machine for inductor conductors for large generators
Project partners: Siemens AG Generatorenwerk Erfurt | Steinbeis-Transferzentrum Antriebs- und Handhabungstechnik im Maschinenbau/Chemnitz
The Siemens AG generator plant in Erfurt is an internationally recognised production site that develops and manufactures turbogenerators with a capacity of up to 300 MW. Ever-increasing competitive pressure calls for new technologies to optimise manufacturing processes. One key area is the production of inductor conductors, which has hitherto been characterised by a high proportion of manual work.
In collaboration with the Steinbeis Transfer Centre for Drive and Handling Technology in Mechanical Engineering, the company has developed a process and a device that make it possible to revolutionise the complex manufacturing process of inductor conductors, consisting of axial and tangential conductors.
The individual tangential conductors, numbering between 15 and 24, are made of electrolytic copper and are up to 64 mm wide, 8.0 mm thick and 1.7 m long. The conductors are soldered on both sides to the axial conductor, which is up to 7 m long. The required radius of the tangential conductor package corresponds to the rotor radius of the generator and is up to 0.5 m. The maximum package thickness is 160 mm.
The conductors are bent manually, one by one and laid on top of one another, using circular tools, and are thus combined to form a conductor pack which constitutes a complete half-coil. The processing time for an inductor conductor pack for one half-coil has so far been 145 minutes. The manual manufacturing process is characterised by a multitude of precise straightening and inspection procedures and is based on years of experience. This manual manufacturing step was in no way in line with the state-of-the-art manufacturing technology currently in use for large generators in industry and needed to be rationalised through the development of a completely new bending technology. The particular challenge lay in eliminating material-induced springback whilst ensuring that there was absolutely no damage to the surface and no change in length of the topmost layers caused by ‘unrolling effects’, as the conductors are already cut to their exact final length. With the development of the new, patent-protected bending process and the corresponding bending machine, the complete inductor conductor package for a half-coil can be manufactured in a single operation. The process time has been reduced from 145 to 27.5 minutes.