Acculign, Inc. © 2014


turbomachinery alignment



Permanently attach benchmarks to the equipment and to the foundation at or near each bearing location.  Where bearing housings are readily-accessible, benchmarks are typically placed as shown in Figure 1. Where bearing housings are not readily-accessible, benchmarks may be placed as shown in Figure 2.  In either case, all benchmarks at a given bearing location lie in a plane normal to the shaft centerline.

When the equipment is brought on line and reaches normal operating temperature, again take and record benchmark gauge readings at each location.  Any movement of the machines from the initial (cold) to the final (hot) condition will be reflected in changes of benchmark gauge readings.

By using PC programs furnished with each benchmark gauge set, the following information can be obtained without stopping the equipment for a "hot check":

SKETCH 401 - sample.pdf

Sketches for required calculations are provided as reusable plastic laminates.  PC programs for these calculations are available on the downloads tab, and may be used with any IBM (or compatible) PC using an MS-DOS operating system. Machine movements can also be determined graphically, if desired. Please download the instruction manual for complete description of the procedure.

Recommendations for placement of benchmarks are furnished with benchmark gauge sets.  After installing the benchmarks, align the equipment in the normal manner and record final alignment readings.  Using the benchmark gauge, measure and record the distance between each pair of benchmarks (A and B in Fig. 1, or A, B, C and D in Fig. 2). Also measure and record the angles at which the readings are taken. Angles are measured using the inclinometer furnished with the benchmark gauge set.