This Standard defines standard classes of flexible
coupling potential unbalance, one of which
the user must select in order to meet the needs of
his system. The balancing requirements for a flexible
coupling depend upon the rotating system into
which it is mounted. The balance classes are derived
from consideration of the potential unbalance
of the coupling. The AGMA method of
computing coupling potential unbalance is provided.
A guide is provided for balance class selection
for purchasers who have not defined the coupling
balancing requirements for their system.
1.1 Application. This Standard is applicable to
ali flexible couplings, unless otherwise specified by
the individual manufacturer. It should be noted
that a flexible Coupling is generally an assembly of
several components having diametral clearance
and eccentricities between the pilot surfaces.
1.2 Exclusions. This Standard does not address
the unbalance effects caused by such items as:
(1) Shaft runout
(2) Keys that protrude beyond the hub or
(3) Unfilled keyways or keyseats
(4) Coupling mounting surface clearance
(5) Non-homogeneous materials
(6) Curved datun
shaft
1.3 Additional Considerations. IS0 Standard
194011, Mechanical Vibration - Balance Quality
Requirements of Rigid Rotors - Part I , Determination
of Permissible Residual Unbalance, may
be used for balancing coupling components and
assemblies in the balancing machine. However,
after the coupling is disassembled and reassembled
either in the balancing machine or the rotor
system, significant potential unbalances are introduced.
These potential unbalances, as addressed
in this Standard, are primarily the result of:a. Balancing mounting fixture inaccuracies
b. Displacement of coupling components
with respect to the axis of rotation of the
rotor system during disassembly and
reassembly of the coupling.