Single Plane Balance 091401
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Transcript of Single Plane Balance 091401
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7/31/2019 Single Plane Balance 091401
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Dr. Peter Avi tabi le Universi ty of Massachuset t s Lowel l Single Plane Balance 091401 - 1 Copyr ight 2001
Mechanical Engineering - 22. 403 ME Lab I I
ME 22.403
Mechanical Lab I I
Single PlaneBalancing Not es
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7/31/2019 Single Plane Balance 091401
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Dr. Peter Avi tabi le Universi ty of Massachuset t s Lowel l Single Plane Balance 091401 - 2 Copyr ight 2001
Mechanical Engineering - 22. 403 ME Lab I I
Why and How Do St r uct ur es Vibrat e?
INPUT TIME FORCE
INPUT SPECTRUM
OUTPUT TIME RESPONSE
OUTPUT SPECTRUM
f(t)
FFT
y(t)
IFT
f(j ) y(j )h(j )
FREQUENCY RESPONSE FUNCTION
Mot or or diskunbalance
can cause unwant ed
vibr at ions or wor se
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Dr. Peter Avi tabi le Universi ty of Massachuset t s Lowel l Single Plane Balance 091401 - 3 Copyr ight 2001
Mechanical Engineering - 22. 403 ME Lab I I
Any init ial unbalance in a r ot at ing syst em can have devast at ing
ef f ect s as t he syst em is st ar t ed up, slowed down or r un at or
near t he cr it ical f r equency.
Operat ing anywher e near st r uct ur al resonances can r esult in ver y
large dynamic loads which are or ders of magnit ude gr eat er t han
t he nor mal st at ic loads.Theref or e, ext r eme car e is exercised in balancing high speed
st r uct ur al syst ems t o avoid any pot ent ial problems.
This labor at or y will delve int o balancing r equir ement s.
Rot at ing Unbalance Pr oblems
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Dr. Peter Avi tabi le Universi ty of Massachuset t s Lowel l Single Plane Balance 091401 - 4 Copyr ight 2001
Mechanical Engineering - 22. 403 ME Lab I I
Bent ly Nevada Rot or kit
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Dr. Peter Avi tabi le Universi ty of Massachuset t s Lowel l Single Plane Balance 091401 - 5 Copyr ight 2001
Mechanical Engineering - 22. 403 ME Lab I I
Relat ed I nst r ument at ion & Signal Condit ioning
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Dr. Peter Avi tabi le Universi ty of Massachuset t s Lowel l Single Plane Balance 091401 - 6 Copyr ight 2001
Mechanical Engineering - 22. 403 ME Lab I I
An eddy- cur r ent probe measur es t he dist ance bet ween a sensor
head and an elect r ically conduct ing sur f ace. The sensor is based
on eddy cur r ent s t hat are induced at t he conduct ing sur f ace as
magnet ic f lux l ines f r om t he sensor int ersect wit h t he conduct ingmat er ial; t he eddy cur r ent s ar e sensed wit h an impedance
(induct ance) br idge.
Eddy Cur r ent Pr obe
The sensit ivit y of t he sensoris dependent on t he t argetmat er ial and illust r at es
higher sensit ivit y f or
nonmagnet ic mat er ials.
For magnet ic mat er ials, at hin f ilm of aluminum, f orinst ance, can be bonded t o
t he st r uct ur e sur f ace.
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Dr. Peter Avi tabi le Universi ty of Massachuset t s Lowel l Single Plane Balance 091401 - 7 Copyr ight 2001
Mechanical Engineering - 22. 403 ME Lab I I
An eddy- cur r ent probe uses a pr oximit or and power supply/ signal
condit ioning unit .
The out put volt age is pr opor t ional t o displacement and has high
sensit ivit y wit h very linear char act erist ics.
Eddy Cur r ent Pr obe
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Dr. Peter Avi tabi le Universi ty of Massachuset t s Lowel l Single Plane Balance 091401 - 8 Copyr ight 2001
Mechanical Engineering - 22. 403 ME Lab I I
The keyphasor is a once per r ev indicat or measur ed by an eddy-
cur r ent probe and shaf t displacement can be measur ed also
Eddy Cur r ent Pr obe - Keyphasor & Displacement
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Dr. Peter Avi tabi le Universi ty of Massachuset t s Lowel l Single Plane Balance 091401 - 9 Copyr ight 2001
Mechanical Engineering - 22. 403 ME Lab I I
Using bot h t he keyphasor and displacement , t he largest and
smallest displacement mot ion of t he shaf t can be det ermined
r elat ive t o t he keyphasor as some angular r elat ion
Eddy Cur r ent Pr obe Measur ement s
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Dr. Peter Avi tabi le Universi ty of Massachuset t s Lowel l Single Plane Balance 091401 - 10 Copyr ight 2001
Mechanical Engineering - 22. 403 ME Lab I I
Using t wo probes in t he x and y dir ect ions, a relat ionship can be
plot t ed wit h x/ y super imposed or plot t ed verse each ot her
Eddy Cur r ent Pr obe Measur ement s
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Dr. Peter Avi tabi le Universi ty of Massachuset t s Lowel l Single Plane Balance 091401 - 11 Copyr ight 2001
Mechanical Engineering - 22. 403 ME Lab I I
The shaf t cr it ical speed is det ermined using a simply suppor t ed
beam wit h a lumped weight f or mulat ion and is
Cr it ical Speed Det erminat ion
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Dr. Peter Avi tabi le Universi ty of Massachuset t s Lowel l Single Plane Balance 091401 - 12 Copyr ight 2001
Mechanical Engineering - 22. 403 ME Lab I I
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Dr. Peter Avi tabi le Universi ty of Massachuset t s Lowel l Single Plane Balance 091401 - 13 Copyr ight 2001
Mechanical Engineering - 22. 403 ME Lab I I
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Dr. Peter Avi tabi le Universi ty of Massachuset t s Lowel l Single Plane Balance 091401 - 14 Copyr ight 2001
Mechanical Engineering - 22. 403 ME Lab I I
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Dr. Peter Avi tabi le Universi ty of Massachuset t s Lowel l Single Plane Balance 091401 - 15 Copyr ight 2001
Mechanical Engineering - 22. 403 ME Lab I I
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Dr. Peter Avi tabi le Universi ty of Massachuset t s Lowel l Single Plane Balance 091401 - 16 Copyr ight 2001
Mechanical Engineering - 22. 403 ME Lab I I