What is Vibration Testing?

A bearing failure in a motor can bring production to a grinding halt. An unbalanced cooling tower on the roof can shake a tenant’s conference room table on the first floor. A failed coupling in a chill water pump can mean early dismissal from an overheated building.

Two plane balance of fan results in smooth operation.

Your plant or office building’s operations depend upon continuous operation of numerous pieces of rotating equipment. One failure in a critical item can result in a chain reaction of severely damaged equipment, lost production and lost revenue. Such failures need not happen. Vibration testing will provide early detection of developing failures in rotating equipment so that repairs can be planned and conducted at your convenience.

How does vibration testing work?

As mechanical or electrical problems develop in rotating equipment, vibration levels increase. These increases occur at specific frequencies that relate to the type of developing fault. A vibration analyzer measures both vibration severity and frequency. By combining these measurements, we can determine the cause and severity of problems developing in your rotating equipment. We use the latest generation of vibration analyzers. All analyzers are multichannel, with the latest analytical features. These instruments greatly reduce the time required to acquire and analyze vibration data. Large numbers of machines may be analyzed rapidly and at dramatically reduced costs. Vibration analysis of your rotating equipment is just as cost effective as infrared testing of your electrical equipment!

What types of problems may be identified by vibration testing?

Our vibration test will identify most of the problems that will make your machines fail. This includes bearing faults, misalignment, imbalance, motor stator or rotor faults, worn belts or sheaves, mechanical looseness or rubs, flow deficiencies in pumps and fans, and more. Vibration analysis can be used to identify sources of objectionable mechanical or HVAC noise and vibration.

How is vibration testing conducted?

For many clients, vibration testing of rotating equipment is conducted in conjunction with infrared and ultrasonic surveys of the entire facility. All data is retained in a computer data base for trending future inspection results. Where large numbers of machines are to be tested (typically between 25-100 machines per day), we develop a customized computer data base of all machines. This facilitates rapid testing and analysis. Many clients opt for periodic monitoring. Test intervals range from monthly to annually. Periodic monitoring permits changes in critical machines to be detected before a failure condition can develop. Finally, indepth studies of specific machines may be conducted to resolve recurring problems, verify proper operation or obtain baseline data for acceptance of new installations. Where required, we utilize advanced techniques such as modal and operating deflection shape analysis. We can correct problems by performing inplace balancing, precision alignment and assist in developing structural modifications.

Examples

Vibration Testing Vibration Testing
Extreme vibration in new 500 HP compressor. The vibration resulted from a resonance in the male high speed impellor. This resulted from improper support of the discharge air line. The upper plot shows reduced vibration when pipe supports were tightened. Bearing fault in a water pump. The fault is demonstrated by peak view and ultrasound spectra.
Vibration Testing Vibration Testing
A roof top air handler was causing loud vibration in the ceiling of a conference room. We balanced the fan. This eliminated the noise from the ceiling grid. The lower plot shows very high vibration in a chill water pump. We predicted a damaged coupling. The upper plot shows vibration after the coupling was replaced.

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