"The numerous example problems included with XLRotor can be used to kick start most modeling efforts."

Ralph Jansen,
University of Toledo

Frequently Asked Questions

1. Can XLRotor calculate indeterminate static deflections?
   
2. Does XLRotor compute bearing reaction forces?
   
3. Can XLRotor produce shear and bending moment diagrams?
   
4. Does XLRotor compute natural frequencies and mode shapes?
   
5. Can XLRotor produce a critical speed map?
   
6. Can bearing stiffness be displayed on undamped critical speed maps?
   
7. Can XLRotor compute response to imbalance?
   
8. Does XLRotor allow stiff supports, and what about pin joints?
   
9. Does XLRotor allow isotropic and/or anisotropic elastic supports.
   
10. Can XLRotor model oil film bearings?
    
11. Does XLRotor include gyroscopic effects?
    
12. What kind of forcing functions can be applied to the rotor?
    
13. Can external moments be applied to the rotor?
    
14. Can XLRotor perform a torsional analysis?
    
15. Can XLRotor generate a Campbell diagram?
    
16. Can XLRotor compute torsional response to motor excitation during machine start ups?
    
17. What numerical methods are used by XLRotor?
    
18. Can XLRotor be customized by the end user?
    
19. What documentation comes with XLRotor?
    
20. What version of Excel must I have to run XLRotor?
    
21. What version of Windows must I have to run XLRotor?
    
22. Can XLRotor be run from a network server?
    
23. How do I get technical support?
    
24. Can my own programs, like bearing programs, be used with XLRotor?
    
25. Can XLRotor compute amplification factors from imbalance response plots?
    
26. Can I choose how I want natural frequencies and damping factors to be displayed?
    
27. Can XLRotor compute operating deflected shapes of the entire rotor due to imbalance at a one or more speeds?
    
28. Can XLRotor be used in either English or SI units?
    
29. Can XLRotor model bearing support stiffness and damping?
    
30. Does XLRotor allow me to specify the same peak scale value for all response plots of displacement and/or bearing load?
    
31. Does XLRotor allow me to choose between peak-to-peak and zero-to-peak for response plots?
    
32. Can XLRotor compute static rotor deflection and bearing reactions for offset or misaligned bearings?
    
33. Are any example cases included with the program?
    
    

Can XLRotor calculate indeterminate static deflections?

Yes. The asynchronous response analysis option can be used to apply arbitrary forces to any or all stations in the model. The frequency of the applied forces can even be zero, which case you get a static deflection.

XLRotor also has a special analysis command for computing deflection due to shaft weight.

Yes, this is done automatically for the bearings you designate when you perform a response calculation.

Yes. XLRotor does generate data for complete shear and bending moment diagrams. This data is computed and written to a temporary file. If the actual diagrams are desired they are quickly created using Excel’s charting features.  An example file is include with the software showing how to do this.

Yes. XLRotor can compute damped or undamped natural frequencies and mode shapes. Special options are also included to make it easy to compute free-free modes and rigid shaft modes.

Yes. XLRotor can compute complex eigenvalue maps as functions of rotor speed (both frequency and damping factor). 

XLRotor also has a special analysis command to produce an undamped synchronous critical speeds map.  This plot shows the synchronous critical speeds as functions of support stiffness.

Yes. There is a pull down menu command for adding bearing stiffness data to undamped critical speed maps.

Yes. XLRotor can compute synchronous response to residual mass imbalance, and also asynchronous response to general harmonic forces.

When working with XLRotor in English units, imbalances can be entered in gm-in or oz-in.

Yes.  You can specify your own stiffness of any value.  XLRotor also allows PINNED, RIGID and GUIDED supports to ground, or between stations.

Yes, and these can be with or without damping.

Yes. XLRotor can model direct and cross coupled stiffness, damping, and inertia coefficients for bearings and seals. It can also include pitch and yaw stiffness, damping and inertia coefficients. XLRotor comes with modules for standard journal bearings, ball bearings, annular seals, and more.

Yes. This effect can be turned on or off with a check button in the General Options dialog box.

Rotating and non-rotating forces, synchronous and non-synchronous. Synchronous forces can vary with square of the rotor speed (i.e., imbalance).

In the transient analysis part of the program, you can specify forcing functions of any kind.

Not at present in the linear response part of the program, but it would be easy to add this capability.

In the transient part of the program, external forces and/or moments can be applied anywhere in the model.

Yes. Version 3 of XLRotor can compute damped or undamped torsional natural frequencies and mode shapes.  You can also compute linear response to any harmonic(s) of shaft speed.

In the transient part of the program you can compute torsional response to just about anything.  Complete machine startups, electrical faults, gear backlash, nonlinear elastomeric couplings, synchronous motor torque pulsations, VSD excitations, etc.

Can XLRotor generate a Campbell diagram?

Yes. This is done automatically as part of every calculation of torsional eigenvalues.

Yes.  This is easily done with the transient analysis part of the program.  Any manner of motor excitation can be analyzed.

XLRotor utilizes the super fast Polynomial Transfer Matrix for models that are single level.  For multi-level models, XLRotor uses the Finite Element Method where specially optimized sparse matrix algorithms are employed.  The sparse matrix solvers used by XLRotor allow all analyses to be done in full "direct" fashion without the need to perform any sort of model size reduction.  There is never the need to select degrees of freedom to be condensed, or to pick the "number of modes" to be included in the analysis.

Yes. Much of the charting and worksheet formats are readily customized. Custom macros can also be written to automate analysis and reporting tasks. One customer has completely automated their "standard analysis" to address things like different imbalance distributions, different bearing clearances, etc., and automatically generate an extensive multi-page report in Microsoft Word.

The program comes with examples illustrating how to automate a series of analyses.

Documentation is entirely online in the form of Windows Help files. These make it very easy to learn to use the software. The help files are context sensitive, so when you press the help button (control-F1) you immediately get help relevant to what you are doing. There is also a tutorial to quickly lead through your first analysis.

Any Excel version starting with Excel 97 (Excel version 8.0).  

XLRotor works with all the current Windows versions.  This includes Win95, Win98, WinME, NT3.5, NT4.0, and Windows 2000, Windows XP. 

In all cases, XLRotor runs as a native 32 bit application. 

Yes. XLRotor can be installed on any system on the network, and can be run from any other system on the network.  

XLRotor utilizes a parallel port security key.  The key can be installed on any computer on the network, and one session of the program can be run anywhere else on the network.

The best way to get help is via Internet email at:

You should generally receive answers to your questions in less than 24 hours, especially if by email. You can also contact us by telephone or fax (512-918-9140).

Yes.  This is one of the most powerful capabilities of the program.  XLRotor is an integrated system of rotor and bearing analysis modules. XLRotor allows end users to integrate their own bearing and/or seal analysis modules (like FORTRAN programs) into the system.  All that is required is to create an Excel spreadsheet driver for your program using the template that comes with XLRotor.  A knowledgeable user can do this without any assistance from RMA, Inc.  But if you need help, we will definitely help you.

Even without creating such a driver, you can still run your program yourself the normal way, and copy the stiffness and damping values to a spreadsheet for "User Defined" bearings.

Yes. There is a pull down menu command to automatically label one or more peaks with their amplification factors. Amplification factors are computed using the half-power point method.

Yes. In the Options Eigenanalysis dialog box you can choose between RPM, HZ, and RADIANS/SEC for frequency values, and between LOG DEC, ZETA, and DAMPING EXPONENT for damping values. You can also convert computed results back and forth among these choices.

Yes.

Yes. You can use customary English units (in-lbf-lbm), strict SI (m-N-kg), and modified SI (mm-N-kg).

Yes. Support mass can also be defined.

Yes. This is done in the Options Response dialog box.  In addition to this, all charts created by XLRotor come from charts templates for which you can alter the formatting to suit your taste.  Chart customizations can be done for all projects, and/or on a project by project basis.

Yes. You can use rms, or any other measure you wish. You can also have displacement displayed as inches, mils, microinches, millimeters, whatever you wish. These selections are made in the Options Response dialog box, and are saved with the analysis file.

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Yes.  An example is included with the program of a utility class turbine-generator with it's bearings misaligned.

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Yes.  There are literally dozens of example cases included with the program.  Many of these are of published analysis examples found in technical papers and textbooks.