6. Maintenance
and
inspection
6.1 Daily
inspection
(1) Check the vibration, noise, current value, etc. of the fan.
If there is any unusual condition, it may be a sign of failure; therefore, take the appropriate
measures as soon as possible.
For this purpose, it is recommended to keep an operation log.
Warning
The main shaft, V-belt pulley, and V-belt are rotating during
operation. Be extra careful not to get your clothes etc. caught in
these parts.
(2) If strong vibrations occur, stop
the operation and inspect the
V-belt alignment, duct
connections, tightening of the
installation bolts and foundation
bolts, and check for
accumulation of dust on the
impeller and damage to the
bearings.
If the vibration is within the range
specified as "Good" in JIS B
8330, it is considered normal
(see the figure on the right).
If a vibration-proof device is
installed on the fan, vibration of
the fan itself becomes slightly
stronger although the vibration is
not transmitted to the foundation.
In such a case, a vibration lower
than the broken line is
considered normal.
(3) In addition to vibrations, noise is
an important factor in judging the
operating condition.
If you hear a metallic sound
possibly made by contact with
the rotor, stop the operation
immediately.
Continuous noise of air flowing inside the casing (such as “Goooo”, “Zaaaa”) is normal;
however, discontinuous noise (such as “ZaaZaa”, “WonWon”) is caused by surging. An
appropriate measure is required in the latter case, for example by changing the damper
opening.
(On the bearing housing)
a - Tot
al
am
pl
it
ude (
ȝ
m)
n - Rotation (mim
-1
)
Acceptable vibration range
Good
Excellent
Acceptable
Unacceptable
With vibration isolator
10mm/s
(4) Bearings generate noise even in normal condition.
Although it is difficult to identify an abnormal noise because bearings produce complicated
noise, learn about the noises thoroughly to prevent an accident.
6-1
