Tagged With "signal"

Topic

ADRE Over / Under Range?

N Glover ·
Hi All! I've been sent some plots from an ADRE system, of an X and Y probe looking at a shaft. One of the plots has "A/D UNDER RANGE (FLAGGED PLOT)" written within the plot area, and the other probe has "A/D OVER RANGE (FLAGGED PLOT)". What do these two statements refer to, and what do they mean? I can understand that the "OVER RANGE" is probably because the actual signal is greater than the signal range in the analysers settings, but what is the "UNDER RANGE"? Also, will the Over range plot...
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Signal Processing in Matlab

Matthew21 ·
Hello, I am looking at learning how to complete signal processing for condition monitoring in house on matlab and was wondering if anyone has any resources they would recommend for this? I have a few resources on signal processing, just less on the actual practical implementation in matlab. Is the signal processing toolbox necessary? Thanks
Topic

Noise signal ????

Vibration Techn. ·
Vibration spectrum was collected from Acceleration 25mV/g's. via vibration module . The vibration signal contain of 500Hz along with multiple Harmonic. Please help advice. Thank in advance.
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CSI2130 pin assignment for pocket laser tach

eisenhans ·
Hi everyone, I want to use a pocket laser tach with the csi2130. Does anyone know the pin assignment at the plug of the CSI2600 ? The pocket laser tach has 2 wires for the positive TTL-Signal. Wich pins are to use ? Thanks
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Signal cables for CSI 2140

Nagaraja ·
Hi, I am looking for signal cables that can be connected to Bentley panel for collecting shaft measurements and key phasor for my CSI 2140 fft analyser. Can somebody help where I can find the source Nagaraja
Topic

Converting Velocity Signal from Velocity Vibration Transducer

DuPlesis ·
Guys, I would like to have inputs from the fellows who have worked with SKF Microlog Analyzer. I have a Permanent installation, stud mounted Velocity Transducer (Make: CEC Model:4-131) installed on Accessory Drive Gear box of Solar Titan 130 Gas Turbine. I want to get Acceleration Data from the BNC Connector of this Velocity Sensor. However, in the setup for Micro log Analyzer when I select Vibration sensor type as velocity sensor the measurement units I get are only for Velocity or...
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Re: Signal cables for CSI 2140

John from PA ·
I see you are from India so start at https://dir.indiamart.com/sear...=1&search_type=p as a suggestion. I see one offering, https://www.indiamart.com/prod...ble-19715696097.html , but I did not spend a lot of time looking.
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Re: Signal cables for CSI 2140

Nagaraja ·
Thanks John....
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Re: Signal cables for CSI 2140

Walt Strong ·
You obviously need the correct analyzer input adapters for AC signals and tachometer, then at least 2 BNC Patch Cables. Search: bnc patch cables in india https://www.bing.com/search?q=...EsA8phmh&plvar=0 Walt
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Re: Signal cables for CSI 2140

ckyjohn ·
Don't forget to turn off power to the tach cable in the 2140 settings before you hook up or you may trip the machine...
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Re: Signal Processing in Matlab

Walt Strong ·
I am curious why you choose MATLAB? I would think the Toolbox would be essential for interface with hardware. What DAQ hardware and computer will you use? How many and what kind of machines will you monitor? There are many practical issues for data collection and management that are beyond the basic vibration signal processing that you would program. Walt
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Re: Signal Processing in Matlab

Matthew21 ·
I am completing a project for my final year of university where I need to monitor a permanent magnet motor and induction motor. However, I won't be exposed to the actual motors for a few months (when I start an internship) and so currently I am preparing for this by learning as much as I can... I have been told to make sure I understand the processing procedure by making sure I am able to do it in Matlab (as it is widely used at my university) using a dummy fault signal. So I am not yet part...
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Re: Signal Processing in Matlab

Walt Strong ·
I do not use MATLAB, but instead use DasyLab. Here are some links to the program and an excellent book on signal processing: Signals, Processes, and Systems: An Interactive Multimedia Introduction to Signal Processing 3rd ed. 2013 Edition by Ulrich Karrenberg (Author) $99.00 527-pages plus includes DVD with DasyLab software and examples From < https://www.amazon.com/Signals...nalysis+with+dasylab > DASYLab 2016 - Data Acquisition System Laboratory From <...
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Re: Signal Processing in Matlab

Shurafa ·
There are several matlab books specializing on vibration analysis. My question may seem trivial but have you done a Google rearch? You may want also to check your university's library. When I was a student, I saw several books on this specific subject (using matlab). In order for someday in your position to sucseed, it would be beneficial to study three subjects: 1- Using Matlab for general engineering problems 2- The basics of electric motors, their malfunctions and the vibration generated...
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Re: Signal Processing in Matlab

Matthew21 ·
Thanks Walt, I'll definitely check that book out and see what i can do about dasylab. Ali, I have found a few books on noise and vibration analysis and signal processing, but was just wondering if anyone with experience had any recommendations. I am currently practicing with Matlab and reading about vibration signal processing, so have those covered, but haven't focused on electric motors specifically too much, so I'll definitely look into them more. Thanks for your help. Matt
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Re: Signal Processing in Matlab

Walt Strong ·
Here is a handy search link for MATLAB code for vibration analysis: https://www.bing.com/search?q=...48E4B0E3BE2C02EFFA6D DC Motor vibration analysis: https://www.bing.com/search?q=...saaxG0%215JjkvJU3cCC AC motor vibration analysis: https://www.bing.com/search?q=...jamtDwudTJ9HQ8NlpR8q Ali gave excellent advice. Walt
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Re: Signal Processing in Matlab

Matthew21 ·
On the topic of signal processing, I see a lot of information on different processing methods to use for rolling element bearings like envelope analysis etc. but not much info on diagnostic methods for journal bearings. Is simply the frequency spectrum gained through fft and things like orbit plots used to diagnose journal bearing faults? Has anyone used more advanced methods like time-frequency analysis using wavelet transforms? Thanks Matt
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Re: Signal Processing in Matlab

Shurafa ·
Signal processing is in fact a wide subject. Based on my limited experience, your observation is correct; there is more literature recently on the rolling element bearings compared to fluid film bearings. With respect to the wavelet analysis, it gained a little interest in the common industry compared to fft. Many practionors do not know what a wavelet is or how it could used in practical machinery vibration analysis. Having said that, I would recommend to identify the scope of your research...
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Re: Signal Processing in Matlab

Matthew21 ·
Sorry, I forgot to mention that these motors are run on hydrodynamic bearings. At the moment the type of motor (likely smaller induction and permanent magnet motors) and the type of bearings is the only information I have been given (and is likely all I will get). So I have been looking at what types of processing is used for fluid film bearings to practice and learn it for myself without the help of a monitoring software system but as mentioned not as lot has been found. I agree that trying...
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Re: Signal Processing in Matlab

Walt Strong ·
Small motors (AC or DC) generally do not use hydrodynamic bearings (fluid film), but instead use anti-friction (rolling element) bearings. Fluid film bearings are best monitored with noncontact proximity (inductive or capacitance) probes embedded in the bearing (typically 2 per bearing at 90-degrees orientation). The obvious concern for bearing condition is that shaft/journal relative vibrations do not exceed the bearing clearance, or a wipe-out would occur rather quickly. In this case...
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Re: Signal Processing in Matlab

Matthew21 ·
Thanks Walt. I won't get anymore information until I get there as its in a different country and run through my uni, so all I can do at the moment is practice and gain general info. You wouldn't happen to know where I could find some journal bearing proximity probe data to practice the shaft position, orbit plots, spectrum and waveform with would you? Thanks Matt
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Re: Signal Processing in Matlab

Shurafa ·
I would agree with the comments from Walt about the expected type of bearing used for classic small motors. So analysts monitoring these machines do not really need deep details about orbit and other plots associated with fluid film bearings. Nevertheless, a very good reference for fluid film bearings is Orbit magazine that is issued by Bently Nevada (GE). The archived articles are free to download and very helpful as many of them explain the theory in a simple language but with industrial...
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Re: Signal Processing in Matlab

Walt Strong ·
Here is a good search link for vibration analysis with Matlab: https://www.bing.com/search?q=...4EE1B2A2E932654805A7 Walt
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Re: Noise signal ????

John from PA ·
Unless I have missed it, do you realize you haven't told us a thing about the machine!
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Re: Noise signal ????

Shurafa ·
John is right. Clear and specific info is needed to give a meaningful advice. Is your question something like: "What is the source of these 500 Hz harmonics?" Regards- Ali M. Al-Shurafa
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Re: Noise signal ????

Vibration Techn. ·
Sorry for miss information. I collected vibration signal from reduction gear box. The input pinion speed 22124 rpm, and output 1800 rpm Generator. Dear John, the unit is the topic "High Vibration Gen during No-load" I wonder about 500 Hz and Harmonic, why have many harmonic of 500 Hz and the amplitude is the same level. I suspected it come from ground loop or error signal, not mechanical problem. Ref. to frequency chart of gear not have 500 Hz. Thank & regards,
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Re: Converting Velocity Signal from Velocity Vibration Transducer

John from PA ·
A previous discussion exists on this forum...see https://www.maintenance.org/to...elocity-acceleration . Suffice it to say that what you want to do is not a recommended practice and hence the reason the option is not offered.
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Re: Converting Velocity Signal from Velocity Vibration Transducer

Walt Strong ·
The velocity sensor only has a F-max of 2000-Hz, so why try to convert to acceleration? I don't know about the SKF software, but CSI allows acceleration display (signal differentiation) in the spectrum view (not waveform). It does not allow sensor definition Velocity->Acceleration for the analyzer, but perhaps the new analyzers and software do. Walt
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Re: Converting Velocity Signal from Velocity Vibration Transducer

Boilermaker ·
With the SKF analyzer and software the vibration data, the time waveform and spectrum units will be in units of the transducer, in your case velocity. However, in the software you can convert the spectral data into displacement and acceleration. Just right click in the spectrum plot and select the unit you want. Right click and select "Reset settings" to bring back to the original unit. The time waveform data is not convertible. In your case it will be in velocity units.
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Re: ADRE Over / Under Range?

John from PA ·
Straight from the Help file. As far as over ranging, there is some headroom and as best I recall it is about 10% to 20%.
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Re: ADRE Over / Under Range?

VibRental LLC ·
If this is the 208 system then it saves the data up to 50% over the Full Scale Range (10 mil FS goes to 15 mils). Yes the samples are labeled "Flagged Data" and can be included or excluded from the plots. If this is the 408 then I am not sure. Talmadge
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Re: ADRE Over / Under Range?

John from PA ·
With respect to the 208P/Adre for Windows software, I do not think the "overhead" for the A/D converter is as high as 50%. That is a spec we (I worked for BN) generally didn't publish but the value of 5% or 20% overhead capability is common in industrial design. I personally would not use anything above the 20% level for either the 208P or 408DSPi.
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