Showa Denki KAIRYU, Instruction Manual

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5.1.1 Abnormal noise
If an abnormal noise occurs, stop operation immediately and perform inspection.
Possible types and causes of abnormal noise:
◇ Bearing noise
Abnormality or end of service life of motor bearings
◇
Contact noise
Impeller or casing deformation/damage
Intake of foreign object
Looseness due to loose bolt
◇
Vibration noise
Please refer to the following section “Vibrations”.
◇
Pulsating noise (unsteady flow noise)
Excessive closing off of flow volume
Excessive resistance of equipment
5.1.1 Vibrations
If vibrations exceed the acceptable values, stop
operation and perform inspection.
Reference values for acceptable vibration
Motor pole count
(P) - Frequency
(Hz)
Rotation
speed
(min
-1
)
Acceptable
vibration value
(µm; p-p)
6 - 50 Approx. 970 Approx. 118
6 - 60 Approx. 1170 Approx. 97
4 - 50 Approx. 1450 Approx. 79
4 - 60 Approx. 1750 Approx. 65
2 - 50 Approx. 2950 Approx. 38
2 - 60 Approx. 3500 Approx. 32
Acceptable value at vibration speed of 6mm/s
Possible causes of vibrations:

Unbalance of impeller due to dust adhesion

Deformation/damage of impeller or casing

Abnormality of motor shaft or bearings

Looseness due to loose bolt

Stall operation; unsteady flow

Transfer or resonance of vibrations from ducts or base

Insufficient rigidity of ducts or base
5.2 Stopping operation and restarting after stopping
When operation will be stopped, consideration should be given to the storage conditions even if the stopped
period will be short. To prevent rusting of the bearings, etc. during the stopped period, turn the impeller by hand
about 10 times once per month, or run it empty for about 5 minutes once per month. Also, when restarting
operation, be sure to perform the same inspections as were done for test operation. In particular, be sure that
nothing is adhered to the impeller and check that there is no corrosion.
Rotation speed (min
-1
)
Acceptable vibration value diagram
Acceptable
vibration value
Acceptable vibration
value when using
vibration-damping
equipment
To
ta
l amplitude (µm)
Acceptable
Unacceptable
Rotation speed (min
-1
)
Acceptable vibration value diagram