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E. Troubleshooting
Vibration
frequency
Synchronous
*
with
f
s
Double
f
s
Triple
f
s
N multiple of
f
s
f
s
Synchronous
with power
frequency
Double the power
frequency
High frequency
( not multiple of
)
f
s
* Is the frequency according with the rev of main shaft.
Most possible
reason
Imbalance
Mechanical loose
Not in middle
Gear fault, liquid
force, mechanical
loose, reciprocating
force.
Oil film eddy
turbulence
Armature fault
Torsional impulse
Shaft is not
lubricate
Other possible reason
1. Eccentric of gear, belt
sheave and bush.
2. Shaft is not in the middle
or curving (if vibration on
the shaft direction is high).
3. Belt fault
4. Syntony
5. Reciprocate force
1. Shaft is not in the middle
or curing ( if vibration on
the shaft direction is high).
2. Belt fault
3. Syntony
4. Reciprocate force
1 x N x
( N is the tooth
f
s
number of the fault gear ).
2 x N x
( N is the paddle
f
s
number of the fault pump
or fan ).
1. Drive belt fault
2. Interferential vibration
3. Beat frequency
Electric fault such as rotor
broken, rotor eccentric,
there phase imbalance and
air clearance not symmetry.
1. Cavitations and
turbulent flow.
2. Frictional force.
Note
If loose is worse,
there maybe
higher multiple
frequency.
Seldom
Amplitude and
frequency of
vibration are
always not steady
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