Some Three-Dimensional Effects of Rotating Stall
SUMMARY A small perturbation analysis of rotating stall in inviscid, incompressible flow is developed from an analysis of Yeh. An isolated blade row is considered having a blade height which is not small compared to the msan radius. A criterion is derived for tie occurrence of rotating stall, the speed of stall propagation and the possible number of stall cells involved. From this the frequency of circumferential flow disturbances can be obtained. An example is given of an application Of the analysis. The main assumptions made are that a large number of small amplitude stall cells are induced at onset of stall, that the radial shift of the streamlines is small and that the absolute exit flow angle is small. Possible explanations are suggested for the observed changes in number of stall cells.
Experimental Investigations of Propagating Stall in Axial-Flow Compressors

 Measurements of velocity fluctuations in stalled operation of an axial-flow compressor have demonstrated that stalling occurs for the most part in well-defined regions over the compressor annulus. These stalled regions rotate without changing shape in the direction of the blade rotation with a speed proportional to, but of smaller magnitude than, the rotor speed. Two principal types of propagating stall were observed, one with the stalled region or regions extending over part of the blade height, the other with a single stalled region over the full blade height.
Ground Fault Protection for Electric Utility Generating Station Medium Voltage Auxiliary Power Systems
Most generating station designs have medium voltage auxiliary power systems with low resistance grounded neutrals.1 In order to provide even higher reliability, the auxiliary power distribution system configurations supply increasingly redundant process equipment.