Characteristics of vertical hard-bearing balancing machines are described which make such machines suitable for gas turbine rotor balancing.

This document specifies:

a. General dimensions and capacities

b. Performance requirements

c. Balancing speed ranges

d. Drive power requirements

e. Balancing machine spindle flange dimensions

f. Test procedures

Proving rotors and associated test masses required for the performance test are described in ARP4162.

Test procedure are described in detail and test log samples along with a polar diagram for evaluating the test results are furnished.

The document ARP588 for vertical, single-plane, soft-bearing balancing machines, the document ARP4050 for vertical, two-plane, hard-bearing balancing machines, ISO 2953, and the available technology of hard-bearing balancing machines have been considered in the preparation of this document.

This document was developed for hard-bearing balancing machines but may also be used for existing soft-bearing balancing machines.

The purpose of this document is to delineate the technical specifications for vertical, rotating type, hard-bearing balancing machines for measuring the amount and angle of unbalance corrections required in a single plane to balance gas turbine rotors (for Glossary of Terms and Nomenclature, see ISO 1925).

Hard-bearing machines have been used for gas turbine rotor balancing for several years. They have largely replaced soft- bearing machines. Hard-bearing machines provide permanent calibration (see ISO (1925) with first-run readout, simple operation, easy adaptation to computerization, and eliminate support locking requirements and windage fluctuations.

This document also delineates performance tests to ensure compliance with the document.

This document was prepared to give a general description of balancing equipment capable of balancing gas turbine rotors either now in service or to be put into service in the foreseeable future. Standardization of balancing machine to rotor interfaces is intended to enable a set of tooling for a particular component to be used on a variety of machines in one capacity range.

This document may also be used as a general specification for purchasers in procuring suitable vertical single-plane balancing machines.

The performance and test requirements may be used for periodic tests and/or after repairs that may have affected the balancing machine's performance. The test procedure shall be the same as described in this document.

The performance and test requirements have been written in terms of "e\dm\da\dr" (minimum achievable residual specific unbalance), and A-units rather than fixed physical values, such as grams, millimeters, ounces, or inches (see ISO 1925).