Hello everyone,

My company builds new machines that contain belt and gear drives.

I'm working with one of our quality personnel to purchase an affordable spectrum analyzer for our final inspection station. We have a CSI 2120 and 1900 that get regular use in our R&D testing lab, and we'd like a similar device at final inspection. The ideal tool will provide good data for shafts rotating as slow as 15rpm up to 1800rpm. I know how to operate these units to some extent and I regularly look at the spectrum plots for diagnostic data but I'm not experienced with the specifications of vibration equipment, which is why I'm asking for help.

Now my questions:
1) I'm told the CSI's are better able to read frequencies in the lower frequency range (under 50cpm) than other devices. CSI's are also quite expensive. Is this still true? What specification on the datasheets best captures this?
2) Because we are building new equipment and not doing condition monitoring, we don't haven't found a need for advanced analysis and reporting features. IME the spectrum plot tells me what I need to know. Also we're looking for something portable, but I'm flexible on size since it won't move around much. Does this offer us opportunity to buy a less expensive unit?
3) Which analyzers might you recommend for our needs?

Many thanks in advance.

David

What are customer requirements? You have many options as long as it meets requirements.

Here's an instrument I rep but see the sales section on this thread or website. Also, I would recommend a number of different ones to at least look at for a better feel and understanding of what you are looking at. I have a listing on the sale items as well but suggest you look at: http://www.vtab.se http://www.onosokki.net or com? But, DLI, COMMCast, Dactron or a number of analyzers will met your requirements I'm sure.

Are you ISO mandate for compliance: also a consideration.

Vendor

You have to look hard(?) for better cost/benefit if you can find one in comparison to this
ME42:
http://www.vtab.se/index.php?page=41&lang=en

you can look at it as a improved 1900 but including PC software using Access database. As almost always you trade human effort and invested money. This is not a route collector. It is used as final inspection tool at a worm gear manufacturer, drench pump producer, car power window electric motor supplier, mining ventilator producer etc. so FFT data can be compared to a reference FFT with a envelope frame, not to be confused with demodulation that it also has. OLI

Sir,
Where in Pennsylvania are you? I have been in the data acquisition field for 37 years and have used everything from tunable filter analyzers to 16 channel data acquisition systems. I have designed a system that uses National Instruments hardware and software and it has been streamlined to require very little from the operator, yet it yields all the data an engineer may need to diagnose a problem, or it can run pass/fail. If you would like, give me a call.
Ron Brook
215-365-1500

Thanks for the quick feedback on my questions 2 and 3. We are looking for pass/fail criteria, rather we want details when a unit does not run smoothly on the initial run test. Our final inspection person has some experience with the csis but is not familiar with other brands. I will look into the brands mentioned.

Any input on my first question?

Yes features come at a cost. Final inspection before delivery is not so easy. You also have the problem that the machine have had limited operating hours and have a higher bearing noise level unless you have 8-10 hour run in period. Machine may also be at reduced load compared to operational. There are several methods to find lo speed bearing faults and they are so far in higher price portables or on-line systems. If you need a lower cost system and to stick my neck out, look for a conventional demodulation function and the possibility to use a 500mV/g accel so there are some signal at lo freq. and when you see funny things, verify with the instrument you have before. OLI

Thanks OLI.

So then the important component for low frequency response is the sensor. I don't need flat response down to some cpm, just need a useful signal.

We use commercially available bearings and our issues with bearings are very infrequent. My focus is issues with gearing, which typically show at 35000cpm and lower. Sometimes we want to verify resonances which can be important between 15-1800cpm.

Yes my view is that the sensor is the first step w/o signal to look at there are no information to analyse then it remains to analyse it. OLI