mycom i160S - Page 107

2203M4JE-MY-iS2-N_2017.04.
Chapter 6 Troubleshooting
Screw Compressor i-series
6-9
Symptom
Direct cause
Root cause
Action
10
Compressor
generates
abnormal
vibration
and/or
sound.
Damaged thrust
bearings.
Operation with
liquid flow-back
Refer to causes of "Liquid
flow-back during startup" and
"Liquid flow-back during
operation" in item 10.
Contamination by
foreign substances
Refer to causes of "Foreign
substances entering the
compressor" above.
Excessive thrust
stress other than
above
・High suction
pressure
exceeding the
level set by
operating
conditions
Re-examine operating conditions,
and improve if possible.
If difficult to improve, review
maintenance interval
management.
Faulty assembly
* Lock nuts
tightened
insufficiently, lock
washer tooth not
bended, rotation
stopper not set to
thrust bearing
gland or spring
washer not
assembled, etc.
Tighten lock nuts to the specified
torque or torque angle (see "7.1
Tightening Angles for Lock Nuts"
in this manual).
Be sure to record data on the
assembly check sheet to prevent
omission of work steps.
Resonance
vibration
This occurs when
the frequency of
vibration comes
close to the natural
frequency of any
component in the
entire vibrating
system, including
pipes and
supports.
In many cases, this symptom is
caused by change in installation
environment (such as change in
piping routes or additive
installation of devices within
machine room, oil level change,
etc.)
→If occurrence of resonance
vibration is a suspected,
contact one of our service
centers.