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This paper deals with a calculation method of eddy current losses and temperature rises at the stator end teeth of hydro generators. It can be used for analysing and evaluating different design variants when optimising the stator core end portion. The calculation method simulates the three‐dimensional local core end field, but uses only a two‐dimensional calculation model. Amongst all the stator teeth it treats the tooth with the highest axial and radial magnetic flux impact. The paper presents a collection of calculation algorithms of the method and provides some results gained for two different stator core end designs.

The paper aims to cover a numerical routine design calculation module for treating the magnetic circuit of hydrogenerators.

A leading manufacturer of hydrogenerators proposed to overcome the standstill in the development of conventional design calculation tools by replacing his existing program module for treating the magnetic circuit of hydrogenerators by a new one based on numerical algorithms. The new module should use the existing interfaces and not change the scope of the existing design program providing hundreds of additional design results. Fulfilling these requirements the numerical calculation module using an enhanced finite integral method had to be self‐organising with regard to everything, e.g. the grid system generation for discretising the calculation area, the handling of the input data including the currents driving the magnetic field, the handling of the boundary conditions and the iterative load case treatment providing the field current producing exactly the required terminal voltage and factor at the machine terminals. Efforts were made for employing grid generation techniques, numerical algorithms and various iteration strategies which were easy to handle and to minimize the calculation time.

The effort necessary for automating the calculation approach so that interference of a numerical field calculation expert is unnecessary was found to be more challenging than handling the numerical algorithms.

The program module is ready for implementation.

The paper describes the transfer of numerical field calculation software into existing tools for routine design calculations.

An accurate calculation of eddy current losses in the stator clamping parts of large hydro generators is a matter of particular interest with the initial design and the design optimization because they can reach high values and produce local thermal hot‐spots due to the non‐linear magnetic behaviour of the clamping plate.

With a fully 3D approach of the generator pole pitch, both time‐harmonic and non‐linear transient finite element analyses are carried out for the eddy currents using a magnetic vector potential formulation.

With the introduction of a novel modelling strategy for the non‐linear clamping plate, the total eddy current losses evaluated from both analysis methods show a good agreement. Nevertheless, the time‐harmonic solution in comparison with the non‐linear transient solution yields different local eddy current distributions in particular with the clamping plate.

The presented analyses use only the fundamental harmonic in the end region field. Further research will need to be carried out for the influence of the higher harmonics in the end region field and again the comparison of both analysis methods.

With the intention of including the numerical analyses with design review and design optimization of the generators, the results obtained from both analysis methods are compared regarding the total eddy current losses as well as their local distributions.

With a fully 3D approach of the generator pole pitch, second order pentahedral and hexahedral edge elements are introduced with both time‐harmonic and non‐linear transient eddy current finite element analyses.