I am making up a database on a paper machine using AMS. When I used the wizard it wanted to activate the SST. Does the SST really work? What makes it do what it does?

I'm not really sure what SST does to the signal, but I'm pretty sure that it requires the use of a 500 mV/g accel.

I don't use SST and I'm not sure why CSI still has it programed into the Wizard to automatically use it. Much better results can be achieved by using PeakVue on low speed applications.

quote:

Originally posted by Danny Harvey:
Much better results can be achieved by using PeakVue on low speed applications.

In order to detect a bearing fault the PeakVue or other demodulation method will be sufficient, but for detection of low frequency vibration, SST with a 500mv accel is needed, IMHO.

The question is: 'if using a 500mv low frequency accelerometer with (if I'm not mistaken) 1 kHz linear response range followed by a sharp roll off, will it pick up frequencies in a higher range excited by a faulty bearing?'

I believe, the answer is "yes" (although it won't be in its linear range). Any other views?

David

This message has been edited. Last edited by: David_G,

I have used SST on slow paper machines since the day CSI came out with it. To say it does anything for the actual data collection other than sort of cleaning up the lowend, I am not really sure. I do know that I can see the actual running speed in the spectrum of 30 to 60 rpm plus harmonics on these slow machines, with no lowend drag or ski slope or what ever the term is now days.

I use a 100 M/V transducer.

To be forced to use it through the CSI wizard is not really good nor is it really bad. And to be honest I never use the wizard to build a database either. I had rather have complete or as close to complete control over what each machine I build, has defined in it. The wizard may be great but I never use it. I guess it is for "speed" in building a database but if I have to go back and change machine after machine to fit what I want, where did the speed go-----oh well.......

Using SST is or causes no big problem as far as I can tell.

Only my opinion and I may be totally wrong.

On slow machines where I have used both PeakVue and SST in some cases I see bearing problems in PeakVue and in some cases in SST, so I used both, rarely I saw same problems in both. Maybe if the bearing fault is old it pop up in one or the other? I never found any reason for it. Olov

In a previous job I used SST to monitor roll bearings on large diameter conductor rolls on an electro galvanising line. There was a lot of electrical interference if we monitored them in line, so we monitored each one in a roll grinding machine when they were pulled for maintenance. The rolls were changed on a periodic basis and were supported by their own bearings during grinding, as opposed to grinding between centres. They turned at 28rpm and we used both SST and Peakvue to see which was best. The dominant problem that we found was flats worn onto the spherical rollers and this would be picked up by both SST and Peakvue. We found the amount of + to - scatter on the SST wavefom gave a good indication of severity. According to CSI, it was important to keep the cable as still as possible and they supplied a magnetic base with a crocodile clip attached in order to do this. A 500mV/g accel was also recommended.

Ralph,

You are not "forced" to use it by the Wizard. It just checks a box when it creates a measurement point below a certain speed (300 I think). You need to uncheck it if you don't want to use it.

Somebody (I think Patrick Lawrence) mentioned here that you can use the Frequency Calculator program to build databases. I usually use the Wizard because it developes all the fault frequencies, but then have to go back and change analysis parameters. I got the impression that using Frequency Calculator, you can get the fault frequencies built in with out having the CSI assigned ap and al sets. I'm going to check it out next time I get a chance.

Back to the use of SST, can it be said that if you are interested in harmonics of running speed or subharmonics then sst may be better, but if you are looking for bearing defects then PeakVue is better?

quote:

Ralph,

You are not "forced" to use it by the Wizard. It just checks a box when it creates a measurement point below a certain speed (300 I think). You need to uncheck it if you don't want to use it.

Thanks Danny.

I was under the impression from what Aubrey said

quote:

When I used the wizard it wanted to activate the SST

that you did not have a choice.

quote:

Back to the use of SST, can it be said that if you are interested in harmonics of running speed or subharmonics then sst may be better, but if you are looking for bearing defects then PeakVue is better?

Danny, Seems like that might be a good statement for slowwww speed stuff.

Sorry about the mixup Ralph. When you are as low on the learning curve as I am you may as well be forced. From what I got here I changed my AP set to remove the SST.

Aub

Aubrey,

After you pull down the motor and pump (or whatever you are building in Wizard), double click on the component and you can set it up with whatever data you have gathered. After you have configured and coupled the components you can got to one of the pull down menus (sorry, but I don't have RBMware available right now) and select "edit measurement point" (I think) and it will give you a list of all the mps. About the 4th colum from the left is the box for "use sst". Just go through and uncheck the boxes if you don't want to use sst.

If you aren't able to find it on your own, post again and I will give you the specifics when I'm at another computer.

Good Luck,

Danny, your close. When you have added all the info on your configuration, the last box pops up and has your measurement point data. The colum after RPM allows you to select SST for the point desired. Make sure there is a checkmark in the active box.
Aubrey, we have been using peakvue for years on our paper machines with great success. Using 500 hz filter (with 1 average) does great.

Quote from Danny:
"if you are looking for bearing defects then PeakVue is better?"

Our paper machines are full of subharmonics and felt noise that are normal to these beasts. Look for the bearing defects.

Just my opinion
Pete