Universal Single Width Fans
9
On start-up and during operation, the unit should operate smoothly with
minimal vibration. It is possible that a higher degree of vibration may be
experienced. Excessive vibration if left unchecked, can cause a multitude of
problems, including structural and/or component failure. The most common
sources of vibration are listed.
Many of these conditions can be discovered by careful observation. Refer
to the troubleshooting section of this manual for corrective actions. If
observation cannot locate the source of vibration, a qualified technician using
vibration analysis equipment should be consulted. If the problem is wheel
unbalance, in-place balancing can be done through the access panel located
on the side of each fan’s tubular housing. Any correction weights added to
the wheel should be welded to either the wheel back (single-plane balance) or to the wheel back and wheel cone
(two-plane balance).
Bases (Foundation and Isolation)
Critical to every fan installation is a strong, level foundation. A reinforced poured concrete pad with a steel base
or inertia base provides an excellent foundation. Bases must be sturdy enough, with welded construction, to
prevent flexing and vibration.
To eliminate vibration and noise from being transferred to the building, vibration isolators
should be used. The fan is mounted directly on the isolation base and must be
supported for the entire length of the fan base angle. Isolators are installed between
the isolation base and the foundation.
After the fan, isolation base, and isolators are installed, the entire assembly must be
leveled. Position the level on the isolation base, not the fan shaft, for proper
leveling. Additionally, the motor and fan shafts must be level and parallel
relative to each other for proper alignment.
Common Sources of Vibration
1. Wheel unbalance
2. Drive pulley misalignment
3. Incorrect belt tension
4. Bearing misalignment
5. Mechanical looseness
6. Faulty belts
7. Drive component unbalance
8. Poor inlet/outlet conditions
9. Foundation stiffness
Vibration
Typical Fan on Isolation Base
