nsp Engr quote:
"The pump is driven by fixed speed motor 3000 rpm (50Hz). Also we have taken data using 12800 Lines of resolution but in our scenario 1X (order) or running speed peak is totally absent from spectrum. That is really something we cannot understand"
I am only wanting to see the low end of the spectrum, with a fixed amplitude scale of 1.0 mm/sec rather than a 4 mm/sec vertical scale. If there is a 1x in the data, this should show the 1x if the data is displayed at this 1.0 mm/sec scale with 6400 line in 10 orders.
I am not sure if you have looked at the spectrum with a vertical scale less than 4.0 mm/sec and expanded out to a 2 or 3 or 4 or 5 orders Fmax or not, in search of the 1x frequency.
Also a 500 Fmax, actually taken at this frequency, will show no more than 10 orders with 6400 lines, making things clearer at the 1 order range. A 500 Hz Fmax (10x) at 12800 lines would or should really separate the frequencies out in a more clear fashion.
I am guessing that the 2970 rpm is the assigned 1x to the measurement point and not the "real" 1x under running conditions.
If there is no 1x in the data, this machine is running extremely good , other than for the 1.19x frequency being there. My guess is 1x and 1.19x are either so close they are not separating with your lines in your data or something is wrong.
I have seen equipment that had VF Drives and the analyst would not even know it. I am not saying this is the case but IMO, it is worth confirming.