Accelerometer Frequency Response - Basics

[acurry]

I am trying to select accelerometers for turning dryer cans in a Paper Mill. Given the cans diameter and our machine speed, the cans run between 55 and 110 rpm. I have some specs for accelerometers, but I am unsure about what I am reading.

From two salesmen, I have specs stating:

1) 120-360,000 cpm @ +/- 10%
60-600,000 cpm @ +/- 3dB.

2) 300-600,000 cpm @ +/- 5%
240-720,000 cpm @ +/- 10%
120-1,200,000 cpm @ +/- 3dB

I am not an expert, but do these look as if they would function properly? Given my rpm, these accelerometers look like they are sized for something a lot faster then my application.

Thanks in advance for any help.

Adam

 

[sms]

None of them will go down to your slowest running speed, but that may not be terribly important. What are your most common failures? If unbalance is one, you probably don't have enough low end. If bearing problems are the main issue, then the accels above are probably fine...

"Why don't you knock it off with them negative waves? Why don't you dig how beautiful it is out here? Why don't you say something righteous and hopeful for a change?" Oddball, "Kelly's Heros" 1970

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[acurry]

Bearing problems are the main issue, but I would want this system to catch whatever else that might be going on.

I am just not that familiar with vibration monitoring. I understand the roller bearings are turning at a faster rpm then the dryer can. However the inner race would turn as the dryer can would. This makes me think I do need more low end for that portion.

This is going to be a major installation, so I want to feel confident in the final decision.

Any other thoughts anyone?

 

[dgallagher]

For low frequency applications such as this, take a look at:

http://www.reliabilitydirectstore.com/Wilcoxon-793L-General-Purpose-Accelerometer-p/wil-793l.htm

Dave G.

http://www.ReliabilityDirectStore.com

 

[RJ2128]

Try using a velocity coil (seismic), you will find this gives you the cleanest data for your application.

 

[OperaHouse]

I worked with someone that had a patent on a bearing monitor. That used the ratio between peak noise spike and the average bearing noise to determine bearing condition.