A Closer Look at Sidebands in the FFT Spectrum

An isometric illustration of a sideband waveform and a maintenance technician dressed in a blue work uniform and hardhat looking at it with binoculars. The man is small in comparison to the size of the waveforms.

There are times when you will observe sidebands in the Fast Fourier Transform (FFT) spectrum. These sidebands are a common occurrence and are often linked to specific mechanical and electrical issues such as gear mesh frequencies, inner race bearing faults, and various electrical anomalies. Understanding their significance requires a deeper examination. Sidebands provide critical insights…

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The 4 Senses of a Vibration Technician

Collecting vibration data is a crucial step in a reliability program. However, it is just one step in the process. Consistently collecting accurate data under varying operating conditions is essential for effective analysis and maintenance. Operating conditions such as speed, load, and production processes must be meticulously documented and followed to maintain consistent data amplitudes…

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A Pump Tale: Misalignment Exposed

Angular Misalignment from video by Acoem USA Offset & Angularity

Vibration data was taken on a motor/pump during initial training on the Acoem Falcon. This pump was chosen based on history and a visual inspection. The visual inspection pointed towards a potential misalignment issue.   Misalignment Diagnosis The Accurex software in the Falcon diagnosed misalignment. This was confirmed by the Acoem EVO laser alignment tool.…

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Flat Bases and Why They Matter

In reliability and maintenance, base-related vibration and alignment problems have been common issues encountered. Problems such as: Soft foot Bearing misalignment within machines – such as motors, pumps, compressors, etc. Seal and bearing failures – related to radial loading, due to tightening down the pump to a base that isn’t flat Hold down bolts becoming…

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What is Frequency in Vibration Analysis?

The bearing defender screen that shows frequencies.

Frequency is as simple as the name implies, it is the number of times an event occurs in a set amount of time. In vibration analysis, we reference frequency to either cycles per second (Hz) or cycles per minute (CPM).   Calculating Frequency & Cycles Per Minute (CPM) The frequency can be expressed mathematically as…

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A Clean Fan = A Clean Balance!

Over hung fan in an industrial facility.

Editor’s Note: This Blog is authored by Brian Rimmer (Freudenberg) & Stan Riddle (Acoem USA) Acoem USA recently provided dynamic balancing training for Freudenberg in Durham, NC, using an Acoem Falcon vibration analyzer/balancer they had purchased.  During the class, Acoem was asked to assist in balancing a large primary air fan.   Inspection of the…

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Using the Bearing Defender as a PM Tool

Acoem’s Bearing Defender sensor is a true wireless 3-channel accelerometer.  It can be used with a tablet or smartphone to detect common vibration problems quickly and easily on a machine-with no training or certification required. It can be used standalone (with a smartphone or other device for the display), or in conjunction with Acoem’s more…

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Gearboxes – Know your Machines

Gearboxes are used in numerous applications, including machine tools, industrial equipment, conveyor belt drives, and just about any power transmission application with rotary motion that requires a change in torque and/or speed. Output speed and torque are always going to be in contrast to each other – if you use a gearbox to increase the…

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Introduction to Wireless Sensors in Condition Monitoring

Condition monitoring is by no means a new concept in industry. In fact, it is so widely regarded as a best practice, that it becomes commonplace in more industries each year. With this increase in awareness, we have seen an influx of options over the years. Simple overall meters, portable analyzers, wired continuous systems, and…

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Is It Mechanical or Electrical?

Analyzing vibration data can be a difficult job. Using VFD (Variable Frequency Drive) motors can make it even more difficult. Pattern recognition is a huge part of this process. However, diagnosing between electrical and mechanical vibration patterns can be challenging.   Is it a Mechanical or Electrical Problem? First, a straightforward way to distinguish between…

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Closing the Loop in Reliability

The Journey of Reliability A machine is identified by the vibration analyst and recommendations are made for repair, the planner orders the parts, management gets together and determines when the repairs are made, and the maintenance team carries out the plan to replace the defective component. Success! We averted disaster once again! … And the…

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Keep It Simple: Common Vibration Problems to Master

Over the years when training “new” vibration analysts, I stress for them to keep it simple. Many analysts believe that you must review time waveform data to analyze all machinery problems. This is not true. However, some problems are impossible to diagnose without it.   Common Machinery Problems in Industry A majority of plant machinery…

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Resonance in Equipment Reliability

Resonance, critical speed, and natural frequency are all very similar terms and refer to the same phenomenon. An increase in equipment vibration, not relating directly to a specific component, is oftentimes caused by one of the many component natural frequencies that are present on every system or object that exists in the known universe. It…

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Good Vibration Data vs Bad Vibration Data

Good and bad data from an industrial machine.

It is important in vibration analysis to know whether the vibration data you are looking at is actually “good data”. Below is a review of the causes and symptoms of junk data, as well as some tips to improve data quality overall in the future.   Reasons for Bad Data A poor electrical connection is…

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Performing Shaft Alignment on a Caterpillar!

Maintenance worker looks at 1000 hp Caterpillar engine attached to a pump in an industrial setting.

Aligning motors to pumps, fans, compressors, etc., it’s what we do. But occasionally we get to assist a customer perform some real “millwright” work! Case in point – a 1000HP Caterpillar engine, driving a backup floodwater pump for a large municipality in the southeast US. This pump is critical to prevent flood water from mixing…

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