Understanding Decibels and Vibration Sensor Orientation (Introduction)
Are you new to vibration analysis, or do you just need a quick refresher on filters, sensors, or vibration data? These tips from Zenco Vibrations break down the core concepts of decibels and vibration sensor orientation. Watch the two short, easy-to-follow videos for insight into how decibel measurements relate to power and voltage, and why sensor orientation is necessary for accurate diagnostics.
Understanding Decibels
This is a very short video that describes the “half power point” in a filter in terms of decibels (dBs) as well as the 0.707 voltage point. It will also describe the linear range of a vibration sensor in terms of its +- 3dB points.
Decibel units are frequently used in vibration analysis and sound measurements. We will explore the simple dB formulas and how to solve them. After watching this video, you will have an understanding of decibels and how a dB change relates to both power and the voltage coming off a sensor.
Understanding Decibels Formulas
These are the formulas we will review in the video to help with you understand decibels
V = Volts, V1 = Initial voltage, V2 = New voltage
P = Power, P1 = Initial Power, P2 = New Power
dB = 20 log (V2/V1)
dB = 10 log (P2/P1)
V=√ (P2/P1) and P=(V2/V1)2
You will understand these formulas and you will understand why a drop of -3dB is called the “half power” point. You will also see how this change is reflected in vibration amplitude and how it relates to the voltages coming off of a sensor. This will also help you understand the use of the 3dB point in sensor calibration and in filters.
This short video by Alan Friedman from Zenco Vibration Experts explains the importance of defining sensor orientation for triaxial accelerometers. Whether you are taking readings on a route or using wireless sensors, this video has important information you need to know!
It’s not enough to know whether you are looking at data from the “X” or “Y” channel of the accelerometer. You have to know the sensor orientation with respect to the machine.
Vibration Faults and Axes
Different mechanical faults show up in different axes. For example, unbalance in a supported rotor shows up at 1x vertical and 1x horizontal whereas angular misalignment shows up at 1x and 2x axial. Not only do we need to know what test point the vibration data came from, we also have to know which axis. Vibration diagnostics are not possible without information about sensor orientation.
Unbalance causes the shaft to vibrate vertically and horizontallyAngular misalignment causes the shaft to vibrate in the axial direction
What is the Orientation?
We need to know which direction the X, Y and Z sensors are facing with respect to the machine. What is the orientation of the sensor? Is the X sensor in the Vertical direction? Is the Y sensor in the Axial direction? This is what mean by sensor orientation, and this is what we need to determine.
Do you have a better understanding of decibels and vibration sensor orientation?
Check out ZENCO’s course schedule and sign up for a course online or in person with Alan Friedman today! https://zencovibrations.com/events/
Alan Friedman
Alan, aka the Vibe Guru, has over 30 years of vibration analysis experience, He has trained 1000’s of students around the world up to Category IV. One of the things that makes Alan a great teacher is his ability to teach people where they are at. Whether you are a math challenged millwright, an engineer or a PhD, Alan will challenge you without overwhelming you. If you are interested in condition monitoring you can also check out his book: Audit It. Improve It! Getting the Most from your Vibration Monitoring Program or hire him for an on-site program audit.
One of the primary challenges of reliably burning coal is managing the corrosion experienced by the furnace heat transfer surfaces. Fireside corrosion remains a leading cause of failure in boiler tube, in both superheater and reheater tubes. Boiler tubes affected by fireside corrosion also may lose 15 mils per year (mpy), or more in extreme cases
One of the primary challenges of reliably burning coal is managing the corrosion experienced by the furnace heat transfer surfaces. Fireside corrosion remains a leading cause of failure in boiler tube, in both superheater and reheater tubes. Boiler tubes affected by fireside corrosion also may lose 15 mils per year (mpy), or more in extreme cases
The Edison Principal has been developed to solve America’s $1.2 trillion corrosion expense by replacing visible rust with black light active fluorescence. Edison Principal is an analogy based on the failure indicator of the common light bulb invented by Thomas Edison.
The Edison Principal has been developed to solve America’s $1.2 trillion corrosion expense by replacing visible rust with black light active fluorescence. Edison Principal is an analogy based on the failure indicator of the common light bulb invented by Thomas Edison.
What is the difference between Brinelling and False Brinelling? What causes Brinelling and False Brinelling? Brinelling is an indentation in the surface of a material; a permanent plastic deformation that occurs when the yield strength of the material has been exceeded.
What is the difference between Brinelling and False Brinelling? What causes Brinelling and False Brinelling? Brinelling is an indentation in the surface of a material; a permanent plastic deformation that occurs when the yield strength of the material has been exceeded.
In 2009, Trico Services was contracted to complete an equipment lubrication audit of a large mill in the southeast that produces liner and corrugated material for containers. This audit was for roughly 2500 pieces of rotating equipment. Upon completion of the audit, Trico was to take the lubrication recommendations and input this data into the MAINTelligence software platform that the facility uses using to manage their plant lubrication programs.
In 2009, Trico Services was contracted to complete an equipment lubrication audit of a large mill in the southeast that produces liner and corrugated material for containers. This audit was for roughly 2500 pieces of rotating equipment. Upon completion of the audit, Trico was to take the lubrication recommendations and input this data into the MAINTelligence software platform that the facility uses using to manage their plant lubrication programs.
Plain and simple: there’s a lot that goes into a preventative maintenance program for hydraulic systems. While it’s a discipline that’s very basic and uncomplicated when you boil it down, there are many tests that need to be performed and plenty of steps where something can be done incorrectly, so it’s critical to the health of your machine that all are done regularly and properly. In order to do this, it’s important that both the system and hydraulic fluid are taken care of, as your fluid and systems are completely interdependent.
Plain and simple: there’s a lot that goes into a preventative maintenance program for hydraulic systems. While it’s a discipline that’s very basic and uncomplicated when you boil it down, there are many tests that need to be performed and plenty of steps where something can be done incorrectly, so it’s critical to the health of your machine that all are done regularly and properly. In order to do this, it’s important that both the system and hydraulic fluid are taken care of, as your fluid and systems are completely interdependent.
In recent years, the tremendous growth of available technologies and the resulting trend towards component miniaturization and increased product reliability has challenged many companies to upgrade their current cleaning operations to satisfy the higher quality standards required by new product designs. Fluorescent cleaning non-destructive testing (FC/NDT) is a new integrated process that combines traditional cleaning methods with fluorescence-based inspection.
In recent years, the tremendous growth of available technologies and the resulting trend towards component miniaturization and increased product reliability has challenged many companies to upgrade their current cleaning operations to satisfy the higher quality standards required by new product designs. Fluorescent cleaning non-destructive testing (FC/NDT) is a new integrated process that combines traditional cleaning methods with fluorescence-based inspection.
Linear and nonlinear vibrations as they pertain to machinery vibration monitoring are not hard concepts to grasp when properly explained. Alian Friedman of Zenco - Vibration Experts, explains the concepts in an easy-to-understand, non-mathematical way.
Linear and nonlinear vibrations as they pertain to machinery vibration monitoring are not hard concepts to grasp when properly explained. Alian Friedman of Zenco - Vibration Experts, explains the concepts in an easy-to-understand, non-mathematical way.
