Pro-Active Maintenance - Laser Alignment Case Study - Power Turbine Alignment

Applied Diagnostics Ltd - Precision with Pride

Introduction

During the commissioning stages of this new 10MW Steam Turbine Package, the Power Turbine needed to be accurately aligned to the high speed gearbox. Both the turbine rotor and high speed gearbox shaft are supported on sleeve bearings. With a top rotational speed of 22,400rpm it is necessary to perform a Precision Laser Alignment, prior to installing the spacer shaft coupling and turbo flex elements.

Laser Alignment Set Up & Dimensions

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Laser Alignment Results

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Conclusions

The graphical results diagram shows that the final alignment between the new Power Turbine and the existing High Speed Gearbox is ‘Good’ in the Vertical plane and ‘Excellent’ in the Horizontal plane. To achieve this vertical alignment it was necessary to place 50.0 ‘Thou’ of shim under the back of the Power Turbine and 42.0 ‘Thou’ at the front. The horizontal alignment was achieved by moving the unit on its jacking bolts. Subsequent test runs during the final stages of commissioning showed no vibration problems relative to alignment.