Phase Difference
Sorry, I did not completely follow the technical description.
I would take a PAPER STROKE CHECK CARD, mounted on a magnet ..........take a real stroke configuration check at each corner of the vibrating body. It is important to take the check kinda in the same basic spot on all 4 corner of the vibrating device sideplate. and I also like to take a stroke check on both sides in the middle.
We are wanting to see if the stroke imprint all the way around looks equal ....similar........or mirror image of each other. In a perfect world this should be so.
A little bigger a little smaller........NOT A BIG DEAL to lose sleep over...it would tell us we are fairly balanced all way around the unit. BUT,
If a large DIFFERENCE is noted.......say all are OK.....except one......LOOK to the corner where one is different and there you should find your problem. IE ........BROKEN SPRING, BUILT UP MATERIAL CAUSING RESTRICTED EVEN VIBRATION in one corner or added weight in one corner.......liners or what ever.
The offset of the vibrator weights will be whatever the mfr set it up at........IE.....1/4" STROKE, 3/16" OR converted to mm measure. We typically want them read the same. If this rig has bolt on vibrators......with some type of offset PIE dial up eccentricity...make sure they are both set on the same setting....
IE.......5 OR 6 OR 7
Hope this helps........George Baker MODERATOR ■
Phase difference
I have been asked to conduct a vibration survey on a vibrating screen 3m X 4.8 m while unloaded. I recorded each corner in the xyz axis at the same time.
The screen runs at 886 RPM (14.7 Hz) with 4.28 G's of acceleration. There is a phase difference of 4 degrees in the vertical plane, between the two exciters.
The screen is also oscillating from side to side with a phase difference of 57 degrees, although the displacement (Pk to Pk) is only 1.2 mm at the discharge and 0.1mm at the feed end.
Can anyone tell me if there is an acceptance limit for this piece of equipment?
Brett ■