Vibration Analysis

Effects of vibration

Unchecked machine vibration can accelerate rates of wear (i.e. reduce bearing life) and damage equipment. Vibrating machinery can create noise, cause safety problems and lead to degradation in plant working conditions. Vibration can cause machinery to consume excessive power and may damage product quality. In worst cases, vibration can damage equipment so severely as to knock it out of service and halt production. Yet there is a positive aspect to machine vibration. Measured and analyzed correctly , vibrations can be used in a preventive maintenance program as an indicator of machine condition, and help guide the plant maintenance professional to take remedial action before disaster strikes.

vib
Benefits of vibration Testing?

 

  • Anticipate problem areas before failure and prioritize actions
  • Reduce spare part inventories
  • Extend the life of existing equipment
  • Reduce consulting costs by putting the expertise in the technician’s hand


Who can benefit from this service?
 
Vibration testing can diagnose common mechanical problems occurring in: Motors, fans, blowers, belts and chain drives, gearboxes, couplings, centrifugal pumps, piston pumps, sliding vane pumps, propeller pumps, screw pumps, rotary thread/gear/lobe pumps, piston compressors, centrifugal compressors, screw compressors, closed coupled machines, spindles.
 
Most common causes of machine vibration?
 
Vibration can result from a number of conditions, acting alone or in combination. Keep in mind that vibration problems may be caused by auxiliary equipment, not just the primary equipment.
The major causes of vibration are:

 

Imbalance: A ‘’heavy spot’’ in a rotating component will cause vibration when the unbalanced weight rotates around the machine’s axis, creating a centrifugal force. Imbalance could be caused by manufacturing defects (machining errors, casting flaws) or maintenance issues ( deformed or dirty fan blades, missing balance weights). As machine speed increases the effects of imbalance increases. Imbalance can severely reduce bearing life as well as cause undue machine vibration.

Misalignment/shaft run out: Machine shaft are out of line. Angular misalignment occurs when the axes if (for example) a motor and pump are not parallel. When the axes are parallel but not exactly aligned, the condition is known as parallel misalignment. Misalignment may be caused during assembly or develop over time, due to thermal expansion, components shifting or improper reassembly after maintenance. The resulting vibration may be radial or axial (in line with the axis of the machine) or both.

Wear: As component such as ball or roller bearings, drive belts or gear become worn, they may cause vibration. When a roller bearing race becomes pitted, for instance, the bearing rollers will cause vibration each time they travel over the damaged area. A gear tooth that is heavily chipped or worn, on a drive belt that is breaking down can also produce vibration.

Looseness: Vibration that might go unnoticed may become obvious and destructive if the component that is vibrating has loose bearings or is loosely attached to its mounts. Such looseness may or may not be caused by underlying vibration. Whatever its cause, looseness can allow any vibration present to cause damage, such as further bearing wear, wear and fatigue in equipment mounts and other components.