Hi,
I am trying to calculate expected vibration value mm/s, so I am doing following steps and have following questions
There are pump and motor on the metal base plate, so I have 2 sources of energy (vibration).
Motor 1800RPM (30hz), assuming unbalanced rotating force is 50 lbs
Pump 900 RPM (15hz), assuming unbalanced rotating force is 25 lbs
1. Analysis setup: Velocity and Acceleration check box selected. (See analysis settings picture)
2. Base has rigid constrains with mounting holes on the bottom base flange (See Load picture)
3. Damping is set as 2.5%. This value I found somewhere for steel. Correct me if I am wrong. (See damping picture).
4. Load -50 lbs was applied to cylindrical surface representing the center of motor rotation.
Since it is centrifugal force, it is not clear how to set it up right. It is changing direction in ZY plane around X and could be -50, zero or +50 lbs depending on the phase. Load frequency is 30hz, where to enter this info? (Question #1)
It is also not clear how to set load phase and what does it mean? (Question #2)
5. Load -25 lbs will be applied to cylindrical surface representing the center of pump rotation.
The same as Question #1, Question #2
6. Dynamic setup is attached in the picture. So, my range of interest is 1…100Hz. Spread per mode settings are not clear. What does it do? (Question #3)
7. On getting results it gives 108 frequencies to plot. Why it gives so many? I asked only 20. How to find the most critical one with highest level of velocity? (Question #4)
Thanks in advance.
