Speed Sensing
Speed Sensing
(OP)
Is anyone using laser tachometers for sensing shaft speed for use with a vibration analyzer? I would like to take vibration data without having to stop the machine to put reflective tape on the shaft and I want an accurate speed measurement. Just interested in your thoughts and troubles that these devices might have.
Thanks, Mbailey
Thanks, Mbailey





RE: Speed Sensing
TTFN
RE: Speed Sensing
RE: Speed Sensing
e.g. 12 spokes, you could sense them and divide by 12.
<nbucska@pcperipherals DOT com> subj: eng-tips
RE: Speed Sensing
To do vibration analysis you should really use a signal which gives you a phase reference signal as well as just speed. Bently Nevada's term for this is 'keyphasor'. It is a pulse which occurs once per revolution and allows the displacement of the shaft to be determined relative to the bearing housing.
Have a look at how the vibration specialists like Bently-Nevada and Emerson CSI take their measurements. Both are best known for their products which use inductive sensing, but they might have an optical version available.
Nbucska's idea is a good one if you can manage with speed only and no phase information. Do you have, for example, a coupling or similar where you could use an inductive sensor to detect the bolt heads as they rotate past the sensor? This could be installed without stopping the machine, although whether you would want to work so close to a rotating coupling is a question to consider. If it is a temporary installation, a mag-mount base which would normally carry a clock gauge could provide an easy method of mounting the sensor.
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If we learn from our mistakes,
I'm getting a great education!
RE: Speed Sensing
RE: Speed Sensing
http://www.reliabilitydirect.com/tachometerproducts/MON-Smart_Laser.htm
RE: Speed Sensing
http://www.bis.fm/bis/pages/browse_productgroups.asp?psid=811&sc=%23660066&pcid=47&pgid=770&pcn=Frequency+%2F+RPM&pgn=Tachometer+Probes
------------------------------
If we learn from our mistakes,
I'm getting a great education!
RE: Speed Sensing
RE: Speed Sensing
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If we learn from our mistakes,
I'm getting a great education!