We use 3 axis accelerometers to measure vibration.

If you need more information my email is gonzalez.silvia@syncrude.com ■

Now I'm trying to get information about measuring vibrations of the screen. I've heard there is a method drawing in the surface of the screen a kind of ellipse, then we measure the ellipse and get the frecuency.

You are talking about taking test cards - usually you take the test cards in 4 corners of the screen if you have elliptical motion you can take the cards also very close to the mechanisms. It wil give the stroke but not the frequency.

To measure the natural frequency you need to do a "impact test" - one accelerometer is enough with two or three you can do modal or operation deflection shapes but I think you are not interested in it now. Another way is to attach a small vibrating motor to the screen and turn the frequency controller - you will feel the screen growing amplitude when it hit the natural frequency. Once you determine the positions and widths of the natural frequencies you can determine the speeds you can run the screens.

regards

Ziggy ■

Hi

There Is a simple methord:

Put a piece of paper 6" x 6" and hold it tight to the vibrating screen surface.with your left hand.

Now move a pencil (In the direction of material flow) kept on the paper .

( Assuming you are a right handed person!!!)

Repeat this at diffrent angles till you get the widest trace.

Measure the bigger trace and you have your amplitude. (2S)

if your screen is running at 1000 rpm then the 2S value should not exceed 8 mm

1500 rpm keep it less than 4 mm

Thos is the practical way we use to test the screen amplitude

Good Luck ■

Hello and welcome to our forum: I see you have lots of help already.........a good thing.

1. here is a G FORCE or vibrating screen acceleration chart.....the stroke size must correlate with the Rpm by the rules of VSMA....."Vibrating Screen Manufacturer's Association"

Refer to chart please.

I shall send next post with stroke check card and explain how to use it.

George Baker Moderator

Attachments

speed stroke slope pg3 incline screen chart_1 (ZIP)

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see this simple magnet device to check stroke and balance of your screener.

GEORGE

Attachments

shortcut to stroke card image 2 (ZIP)

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IF you just try to double click........it quite often will NOT OPEN.

Why???? Why does the sun rise??? smile.

But, if you right click and click on OPEN........it works fine.

PS: this is a PDF, ZIPPED FILE.

Try this please.

ON THE VSMA HANDBOOK.........look back in this forum and you will find the address to contact. INEXPENSIVE ALSO.

Hoping this all helps................George Baker MODERATOR ■