Articles: Vibration Analysis

2009 PdM Program of the Year Award Winners

Primetime Programs receive award from Uptime Magazine

A Better Understanding of Rotor Dynamics and Support Stiffness

More Data Provides More Answers

by Ron Brook

A Tough Diagnosis - The Saga of the Never Ending Problem

by Greg Davison

You are often told that there is never just one problem with a machine. My very first vibration class taught me that a phase and magnitude vector was a combination of all the vibration from all of the forces acting upon the machine. Likewise, a spectrum also contains all of the frequencies from all of the forces acting upon a machine. So, it is never just imbalance, or just misalignment. It is always some combination of many forcing frequencies. This is precisely why wall charts and cookie cutter solutions do not always work. What follows is a story of multiple problems of mythical proportions.

 

Balancing a Generator at a Hydro Electric Plant

Just two years after installation of a new turbine-generating unit at the 93-MW Thompson Falls hydro project, PPL Montana LLC noticed increasing vibration values on the generator guide bearing. After several unsuccessful attempts to correct the problem, plant personnel adjusted the clearance on the guide bearings. Since that work was completed, the unit has operated within acceptable vibration values.

Flake Breaker Vibration Analysis Case Study

by Ronald Blay, Lead Analyst, Allied Reliability - Cargill Oil Seed, Fayetteville, NC

This is a Flake Breaker Vibration Analysis Case Study at the Cargill Salt Division Watkins Glen plant 

How is Machine Vibration Described?

By Commtest Instruments

To analyze the condition of a machine you first need to accurately describe the behavior or symptoms of the machine.

How can vibration symptoms be described accurately?

How do vibration analysts describe the condition of a machine?

In this section we present the basic methods of describing machine vibration.

After reading this section you will:

• Know the two most important methods of describing machine vibration
• Understand the term 'amplitude'
• Understand the term 'frequency'
• Understand what a spectrum or waveform is

 

 

Refining a Refiner with 4-20 mA Monitoring

by Ed Nisbett, Tim Gilliss and Tom LaRocque

In their mill that is located in East Millinocket, ME (“The Town that Paper Made”), Katahdin Paper Company, LLC, produces pulp, which is used in the production of directory paper, from two paper machines.  Prior to paper production, the characteristics of the wood pulps are adjusted accordingly by passing them through a refiner with patterned rotating plates (see Figure 1).

Structural Failures in Vibrating Screeners at a Petrochemical Plant

Finding A Cure for Troubling Failures

by Maki Onari and Eric Olson

The Challenges of Automated Spectral Analysis

Reflections on eighteen years of development by Jason Tranter, Managing Director, Mobius Institute

The Road to PdM Excellence - Achieving Vibration Analysis Best Practices at Orange County Sanitation

The Orange County Sanitation District (OCSD) is a public agency that serves 2.5 million people in central and northern Orange County. OCSD treats more than 230 million gallons of wastewater every day (enough water to fill Anaheim stadium nearly three times each day), making it the third largest wastewater treatment agency west of the Mississippi River.

Transitions - When to Move from Walk-Around to Online Systems for PdM

by Dennis Shreve

Rotating equipment in production facilities offers optimal performance and reliability when properly installed, maintained, and operated.  Condition monitoring devices and systems are utilized to keep tabs on the operational performance of key production equipment.  All types of tools and technologies exist today in the predictive maintenance field to allow monitoring and assessment of such equipment.

Using Vibration Monitoring Equipment For OTHER Functions

by: Steve Goldman, P.E. - Author of Vibration Spectrum Analysis

 

Introduction:

In recent years, it has become rather common for large and medium sized facilities to begin predictive maintenance programs employing narrow band FFT- based vibration analysis equipment. The cost savings involved in this sort of quality predictive maintenance program easily justifies the ten to twenty thousand dollar cost of the data gathering box and related software.

The popularity of these new data gathering boxes is such that one is more likely to find one of these compact devices in the maintenance department of a given plant than to find a fully equipped dual channel spectrum analyzer in the engineering department.

Thus, a strange thing has happened over the years: the Maintenance Department has become better equipped to handle some engineering problems than the Engineering Department. While the predictive maintenance technician may well gloat over his superior capabilities in the area of vibration measurement, he should recognize a higher responsibility to his employer by learning some of the non-P/M applications of his FFT-based box. With some additional training, the P/M technician can assist Engineering in solving some of the engineering problems which may cause his company the loss of future sales or the damaging of their reputation for quality, causing harm to the Company Profit and Loss statement.

This article will discuss some of the areas in which the user of a hand-held FFT monitoring device may be pressed into service to help solve engineering problems for the Quality Control, Manufacturing Methods, Engineering, and the Service departments of a manufacturing plant. Be warned at the outset, however, that a hand-held device is no match for a fully equipped dual channel spectrum analyzer. We are talking about making do with what you have, not about what could be done with the proper equipment.

Vibration Analysis of Wind Turbines

by Jason Tranter

Wind turbines are dotted across the countryside, seaside, and even offshore. Many believe they are the answer to global warming and stopping the reduction of fossil fuel reserves. Whether you enjoy seeing them on the horizon, majestically spinning in the breeze, or believe they disturb the previously unspoiled landscape, for all of us in the reliability and condition monitoring fields, they pose a new challenge - we have to keep them turning!

 

Vibration Analysis Reporting - Bearing Failure Stages & Responses

This technical note has been written to act as a guide to vibration analysts and maintenance personnel. It outlines the expectations that maintenance personnel should have w.r.t. reporting of bearing defects identified in vibration spectrums.

Visual Acoustic Analysis Ends Super Calendar Mystery

by Daniel T. Ambre, P.E.

This article shows an interesting example of how Acoustic Analysis methods were used to solve a stubborn vibration problem where Experimental Modal Analysis and Operating Deflection Shape Analysis fell short.

 

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