measuring vibration using non-contact method

Thread Starter

Mohit Sangavikar

Joined Sep 18, 2017
2
Hi guys,
in our company's previous design, we used piezo sensor to measure the vibration of a device. this "contact " approach is causing us troubles in geting the required certifications.
I am thinking of a non-contact method, something in the lines of laser doppler vibration sensing. the measurement should be done 10 m away from the vibration source(its an oil drilling system) .
If anyone has any leads or source or details or a better solution as to how to approach the problem, it would be appreciated
 

BR-549

Joined Sep 22, 2013
4,938
What is the mass and size of the vibrating device? What is the displacement of this vibration?
Is the vibration audible? Is the vibration isolated....or in the presents of other vibrations?
What is the environment of the 10 meters?
 

Thread Starter

Mohit Sangavikar

Joined Sep 18, 2017
2
mass of vibrating device: 50-500 kg (we are testing on a bunch of products from drill machines- power plant turbines)
the vibration is audible
the source is the only device in the plant that would make vibrations so yes it's isolated
a 65 metre x 35 metre factory hall
 

BR-549

Joined Sep 22, 2013
4,938
Which character of the vibration do you want to measure? Amplitude? Frequency? Physical displacement?

Is there a stationary non vibrating area close to the vibration for reference?

You said it was audible........are earplugs required/advised? Does the tone sound pure or harmonic?

And with those sizes......what ranges of the measured character would be required?
 

BR-549

Joined Sep 22, 2013
4,938
One simple solution might be a laser pen, a reflector and some graph paper or a wall projection.

or..... another solution might be a magnetically attached and aligned wireless accelerometer.

It all depends on what you are using the vibration measurement for.
 

Janis59

Joined Aug 21, 2017
1,379
RE:""If anyone has any leads or source or details or a better solution""
I am for that need (for car diagnostics) using just most cheapest Chinese (ebay) vibration meter (sorry, contact type but for 10 bucks only) what is showing the amplitude, acceleration, velocity and maximum spectra frequency. Thus to find out what is resonating at that frequency becomes very easy, and amplitude shows the severity of problem, alias mass of resonating detail.
 

crutschow

Joined Mar 14, 2008
28,536
A laser approach could measure vibration up and down but not side to side, so to get all vibration modes you would likely need three detectors orthogonal (XYZ) to each other.
 
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