Abstract: Apparatus for measuring precise distances between the turbine shaft and the interior surfaces of the inner and outer cylinders of a turbine is disclosed. A mandrel carrying proximity transducers is placed inside the inner and outer cylinders and rotated to preselected points. A proximeter generates a radio frequency electromagnetic field which is radiated in the immediate area of the proximity transducers. Energy losses caused by eddy currents generated in the interior surface of inner and outer cylinders are converted into linear output by a computer. Distances between the interior surface of the turbine and the transducers are calculated from the linear output. Comparison of measurements made with the top halves of the turbine removed with measurements made with the turbine halves installed permit determination of the "sag" in the turbine spindle introduced when the turbine is assembled.

Abstract: A method and apparatus for measuring precise distances between the turbine shaft and the inner cylinder is disclosed. A mandrel carrying proximity transducers is placed inside the inner cylinder and rotated to preselected points. A proximeter sends a voltage to the transducers and the voltage drop from the transducers to the preselected points on the inner surface of the inner cylinder is measured. Then, the top halves of the turbine are installed and voltage drop for the same points is recorded. A computer compares the voltages and converts the difference into engineering units to allow determination of the "sag" in the turbine spindle that will be introduced when the complete turbine is assembled.