INMT-2301 Alignment Terms
Air Gap - answer The internal gap between a motor's rotor and stator. Excessive
misalignment forces can change this gap, causing excessive vibration and heat
resulting in premature electrical failure of the motor.
Alignment - answer The placement of two or more machines, such that when complete,
the shaft centerlines of the machines are collinear.
Angularity - answer Angular relationship between movable and stationary shafts.
Typically expressed as a slope, or rise over run, relationship. Imperial units are mils/in.
Metric units are mm/100 mm.
Axial - answer The positioning of machine components along an axis, or centerline.
Axial Run out - answer1) The measurement of machine component eccentricity, due to·
machining errors, bent shafts, or other damage. 2) The measurement of endplay or
deflection along the axis or rotation of a shaft or rotating component
Axial Spacing - answer The distance between two coupling hubs which is required for
proper coupling operation, minimizing thrust forces on bearings, and maintaining proper
magnetic centering of the motor.
Backlash - answer Looseness in coupling that allows for torsional/twisting play between
shafts.
Base-Bound - answerA problem that arises when the piece of equipment you wish to
move is sitting too high and there are not enough shims to remove to lower it.
Baseplate - answerA heavy, flat metal plate, normally grouted into concrete, onto which
machine components are mounted.
Belt - answerAn elastomeric band which is attached to two or more machines, used to
transmit power by rotation.
Belt Alignment - answerThe positioning of shafts, sheaves, and/or pulleys so that
excessive radial or axial forces are minimized.
Bolt-Bound - answerA problem that arises when the piece of equipment you wish to
move cannot be adjusted any further horizontally because the foot is hitting the hold
down bolt.
, Bracket Sag - answerSagging of dial indicator brackets due to the overhung weight of
the bracket and dial indicator, which tends to bend the bracket toward earth due to
gravity. The amount of bracket sag must be measured and compensated for when using
dial indicators for shaft alignment.
Bucking In - answerA process used to rough in measuring tools. The process consists
of making rough adjustments to the measuring device until adequate range is obtained
to complete a measurement. Similar to roughing in.
Cardan Shaft - answerA shaft that is intentionally offset (inches or feet) by means of a
universal joint at either end of the drive shaft. Typically used when the driven element
must move during operation (a roll moving in and out of nip, etc.).
C-Face Flange - answerA machined flange used to mount a motor onto a machine
which is being driven.
Chain Coupling - answerA coupling which uses a short segment of double chain to
connect two coupling hubs. Slight misalignment is compensated by the sliding motion
between the chain links and hub teeth.
Charge Coupled Device - answerA device which converts light into a digital form,
normally used when extreme accuracy is required.
Cogged Belt - answerA belt that has teeth molded directly into its surface, which mesh
with corresponding teeth in pulleys. A cogged belt is designed to avoid slipping and is
also known as a timing belt.
Collinear - answerPositioned on one line. The purpose of shaft alignment is to position
the centerlines of rotation of two or more shafts so they act as one. All centerlines
should rotate on one line.
Coning - answerA method of centering a laser device by rotating the transmitter(s) to
form narrower "cones" of the beam, thereby minimizing the base of the cone.
Coplanar - answerA set of points existing in space so that all points exist in the same
plane. When two or more shaft centerlines are in alignment, all points about the shafts
exist in the same plane.
Coupling - answerA device for connecting two rotating shafts for the purpose of
transmitting power.
Coupling Lockup - answerWhen severe coupling misalignment causes coupling
clearances to be essentially zero, making the coupling no longer flexible. Normally
results in high vibration and damage to the coupling. The high vibration is often
transmitted to the bearings and seals causing them to fail prematurely.
Air Gap - answer The internal gap between a motor's rotor and stator. Excessive
misalignment forces can change this gap, causing excessive vibration and heat
resulting in premature electrical failure of the motor.
Alignment - answer The placement of two or more machines, such that when complete,
the shaft centerlines of the machines are collinear.
Angularity - answer Angular relationship between movable and stationary shafts.
Typically expressed as a slope, or rise over run, relationship. Imperial units are mils/in.
Metric units are mm/100 mm.
Axial - answer The positioning of machine components along an axis, or centerline.
Axial Run out - answer1) The measurement of machine component eccentricity, due to·
machining errors, bent shafts, or other damage. 2) The measurement of endplay or
deflection along the axis or rotation of a shaft or rotating component
Axial Spacing - answer The distance between two coupling hubs which is required for
proper coupling operation, minimizing thrust forces on bearings, and maintaining proper
magnetic centering of the motor.
Backlash - answer Looseness in coupling that allows for torsional/twisting play between
shafts.
Base-Bound - answerA problem that arises when the piece of equipment you wish to
move is sitting too high and there are not enough shims to remove to lower it.
Baseplate - answerA heavy, flat metal plate, normally grouted into concrete, onto which
machine components are mounted.
Belt - answerAn elastomeric band which is attached to two or more machines, used to
transmit power by rotation.
Belt Alignment - answerThe positioning of shafts, sheaves, and/or pulleys so that
excessive radial or axial forces are minimized.
Bolt-Bound - answerA problem that arises when the piece of equipment you wish to
move cannot be adjusted any further horizontally because the foot is hitting the hold
down bolt.
, Bracket Sag - answerSagging of dial indicator brackets due to the overhung weight of
the bracket and dial indicator, which tends to bend the bracket toward earth due to
gravity. The amount of bracket sag must be measured and compensated for when using
dial indicators for shaft alignment.
Bucking In - answerA process used to rough in measuring tools. The process consists
of making rough adjustments to the measuring device until adequate range is obtained
to complete a measurement. Similar to roughing in.
Cardan Shaft - answerA shaft that is intentionally offset (inches or feet) by means of a
universal joint at either end of the drive shaft. Typically used when the driven element
must move during operation (a roll moving in and out of nip, etc.).
C-Face Flange - answerA machined flange used to mount a motor onto a machine
which is being driven.
Chain Coupling - answerA coupling which uses a short segment of double chain to
connect two coupling hubs. Slight misalignment is compensated by the sliding motion
between the chain links and hub teeth.
Charge Coupled Device - answerA device which converts light into a digital form,
normally used when extreme accuracy is required.
Cogged Belt - answerA belt that has teeth molded directly into its surface, which mesh
with corresponding teeth in pulleys. A cogged belt is designed to avoid slipping and is
also known as a timing belt.
Collinear - answerPositioned on one line. The purpose of shaft alignment is to position
the centerlines of rotation of two or more shafts so they act as one. All centerlines
should rotate on one line.
Coning - answerA method of centering a laser device by rotating the transmitter(s) to
form narrower "cones" of the beam, thereby minimizing the base of the cone.
Coplanar - answerA set of points existing in space so that all points exist in the same
plane. When two or more shaft centerlines are in alignment, all points about the shafts
exist in the same plane.
Coupling - answerA device for connecting two rotating shafts for the purpose of
transmitting power.
Coupling Lockup - answerWhen severe coupling misalignment causes coupling
clearances to be essentially zero, making the coupling no longer flexible. Normally
results in high vibration and damage to the coupling. The high vibration is often
transmitted to the bearings and seals causing them to fail prematurely.
