Maybe I am missing something, but a forward whirl is a whirl orbit in the direction of rotation and a backward whirl is an orbit in the opposite direction to rotation. By this definition then there cannot be whirl at zero speed.
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Dr Michael F Platten
I had a belt CVT (Jatco I think) on a Dodge Caliber/re for 3 years. You very quickly get used to the "motorboat" effect of revs not being linearly related to road speed - less than 1 week of living with the thing. The super-relaxed revs at high speed cruising was lovely. I really don't have a...
I drove one for a couple of years on a Dodge Caliber. It was a Jatco unit rated to about 250 Nm - I think they make them up to 400 Nm or so. It had a torque converter for launch and no engine braking.
The drivabililty was excellent (I guess that's the whole point of a CVT). Cruising was relaxed...
What happens if you measure the driving point FRF? If you still see the phase drift then there is something wrong with your hardware setup and/or signal processing.
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Dr Michael F Platten
Not really an answer but another question...
Why on earth would someone use 1 uPa instead of 20 uPa as a reference (unless it was in some sort of low pressure environment?
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Dr Michael F Platten
The noise performance will vary significantly with the misalignment of the gears that occurs in the real gearbox due to shaft, bearing and housing deflection. At the very least you should design in to your test rig the capability to misalign the gears to cover the range of possible misalignments...
You high pass filter when doing this sort of thing to avoid drift problems when you integrate. Just removing the DC isn't usually enough.
Ta
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Dr Michael F Platten
You could try running the signal through the filter twice - once forward and once backward - to remove filter phase effects. Also you should check that you are doing the transforms correctly: a useful check is to see if you have any imaginary part in your final result (you may see some imag part...
There are cycloid drives that are used in sediment separators. They provide a high speed drive to in inner and outer component with a small but high torque speed difference between inner and outer. Two motors running at slightly different speeds are used - maybe this is the dual frequency bit...
It depends on your definition of those things! There is no standard definition. In rotordynamics terms, a Campbell diagram plots natural frequency vs RPM with the shaft orders plotted on top, You can then see the danger areas where natural frequency coincides with rotation order (critical...
No, when operating at high speed, hydrodynamic bearings have stiffness and damping properties that vary with speed and hence the natural frequency varies with speed.
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Dr Michael F Platten
Hmm. If you use a Hann window then your resulting acceleration signal will be Hann window shaped (ish). If you have a long signal, then just taper the ends with a 1/2 cosine shape and leave the middle bit flat. Just make sure that the period of the cosine taper is much less than any of your...
I have done this for real quite a lot in the past. The best way to do it is to use a cosine taper window at the beginning and end of the signal - then do the integration in the frequency domain. You will lose fidelity of the integrated data in the region of the tapers but the rest will be good...
No, A scissor gear is an anti-backlash gear. 4th gear on the input has a small part on the left hand side that is slightly offset rotationally from the rest of the gear. This is spring loaded relative to the main part of the gear so that backlash is eliminated from the gear mesh.
These are...
They are identification marks. The grooves do not extend below the tip chamfer so they do not act as stress raisers as no contact occurs there.
More to the point - What is that transmission from? Is that really a scissor gear on the input shaft 4th speed? That must really wreck the efficiency...
