Description / Abstract:
This SAE Aerospace Recommended Practice (ARP) specifies the
requirements of balancing machines that make them suitable for the
subject class of work. it was developed for soft-bearing balancing
machines but may also be used for hard-bearing machines until
ARP4050 is issued for that type of machine.
Purpose:
This Aerospace Recommended Practice (ARP) delineates the
technical specifications for the rotating type of soft-bearing,
single place (i.e., static) balancing machine used for measuring
the amount and angle of unbalance in gas turbine rotors.
This document also delineates performance tests to be used to
ensure conformance with the requirements in this ARP.
This document was prepared to describe dimensional and
performance requirements for machines capable of balancing most
rotors either now in service or to be put into service in the
foreseeable future. This will enable both rotor and balancing
machine manufacturers to standardize, avoiding the need for
separate tooling to adapt a particular rotor to a variety of
machines in one capacity range. It can also be used as a general
specification by purchasers (users) in procuring suitable balancing
machines from manufacturers (suppliers).
To make this ARP sufficiently flexible so that it can be adapted
to a variety of applications (such as rotors to be balanced by the
accessory and missile industries where a wide range of balance
tolerances are specified), the test procedures have been written in
terms of A units rather than fixed physical values such as ounces,
ounce-inches, or micro inches.
Particular note should be taken that this ARP only examines the
capability of a balancing machine to indicate the correct amount of
static unbalance in specified proving rotors. Such rotors are
commonly used for testing balancing machines to provide precisely
controlled and comparable test results. Further tests of a
particular machine may be necessary to assess its capability to
balance rotors of different weights and configurations and those
with disturbance causing features, such as rotors subjectto
blade scatter, wind age, etc.
This ARP specifies dimensional and performance requirements in
the following areas:
a. Machine capacity relating to weight and physical dimensions
of rotors that can be balanced
b. Accuracy of amount and angle indication
c. Sensitivity and linearity of amount indication
d. Ability to measure static unbalance unaffected by couple
unbalance
e. Balancing speed and direction of rotation
f. Drive requirements
g. Standard drive adapter flange requirements
h. Proving rotors, test masses, and rotor safety enclosures