What clients say:

I have known Brian Murphy since the days of RAPP and PUP. XLRotor is an excellent rotor dynamic analysis software. I have been using XLRotor since its inception and found the program to be very user friendly and easy to learn. The spreadsheet format allows varying degrees of analysis in a time efficient manner, quick and easy checks on the input data, and flexible format plots to satisfy changing customer needs and API requirements. The bearing and seal codes are tops in the industry. If you have any questions on the software or rotor dynamics in general, Brian and Daniel are tops in their field and respond in a timely manner.

Allan Mathis
Principle Mechanical Engineer, Rotating Machinery Services, Inc.

FAQs

 Help Center

Can XLRotor calculate indeterminate static deflections?

Yes. There is an easy way where with one mouse click, the program will automatically select support stiffnesses and apply the force of gravity to the model. In addition, static deflection due to any set of arbitrary forces can be calculated with an asynchronous response analysis at zero frequency.

Does XLRotor compute bearing reaction forces?

Yes, this is done automatically for the bearings designated for load output when performing a response calculation.

Can XLRotor produce shear and bending moment diagrams?

Yes. Complete shear and bending moment diagrams can be output automatically for the entire model by simply turning an output option.

Does XLRotor compute natural frequencies and mode shapes?

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.

Can XLRotor produce a critical speed map?

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.

Can bearing stiffness be displayed on undamped critical speed maps?

Yes. There is a pull down menu command, and a button on the XLRotor ribbon, for adding bearing stiffness data to undamped critical speed maps.

Can XLRotor compute response to imbalance?

Yes. XLRotor can compute synchronous response to residual mass imbalance, and also asynchronous response to general harmonic forces. XLRotor offers a wide choice imbalance units for input; gm-in, oz-in, gm-mm, etc.

Does XLRotor allow stiff supports, and what about pin joints?

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

Does XLRotor allow isotropic and/or anisotropic elastic supports?

Yes, and these can be with or without damping and inertia coefficients. A choice of worksheets are available to allow input of from 8 to 48 linear force coefficients.

Can XLRotor model oil film bearings?

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.

Does XLRotor include gyroscopic effects?

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

What kind of forcing functions can be applied to the rotor?

XLRotor allows analysis with both rotating and non-rotating forces, of either synchronous and non-synchronous variety. Synchronous forces can vary with square of the rotor speed (i.e., imbalance). In the transient analysis part of the program, completely arbitrary forcing functions of any kind can be specified.

Can external moments be applied to the rotor?

Yes. External forces and/or moments can be applied anywhere in the model.

Can XLRotor perform a torsional analysis?

Yes. 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 nearly anything. Complete machine startups, electrical faults, gear backlash, nonlinear elastomeric couplings, synchronous motor torque pulsations, VSD excitations, etc.

Can XLRotor generate a Campbell diagram for torsional systems?

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

Can XLRotor compute torsional response to synchronous motor excitation during machine start ups?

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

What numerical methods are used by XLRotor?

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 model size reduction. This eliminates the need to select degrees of freedom to be condensed, or to pick the “number of modes” to be included in the analysis.

Can XLRotor be customized by the end user?

Yes. Much of the charting and worksheet formats are readily customized. Custom macros can also be written to automate analysis and reporting tasks. Some customers have 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 usingh Excel’s built in Visual Basic macro language. In addition, the various API Analysis worksheets can easily automate a series of analyses without the need to write any macros.

What documentation comes with XLRotor?

Documentation is entirely online in the form of compiled Windows Help files (*.chm), and a 400+ page pdf file reference manual. These documents make it very easy to learn to use the software, as well as to find material on any particular topic. The help files are context sensitive, so when you are working in XLRotor and press the XLRotor help button (control-F1) you immediately get help relevant to what you are doing. There is also a multi-part tutorial which will quickly lead you through your first analysis.

What version of Excel must I have to run XLRotor?

Any Excel version starting with Excel 2003 (Excel version 11.0). In the case of Excel 2010 and later, XLRotor can be used with either the 32 or 64 bit version of Excel.

What version of Windows must I have to run XLRotor?

XLRotor works with all Windows versions which can run Microsoft Excel, from Windows XP through Windows 10, in either 32 or 64 bit versions. XLRotor runs as either a 32 bit or 64 bit application to match that of Excel.

Can XLRotor be run from a network server?

Yes. XLRotor comes with network server software that allows XLRotor to be installed and run on any system on the network.

How do I get technical support?

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 at 512-592-7606 or fax at 512-918-9140.

Can my own programs, like bearing programs, be used with XLRotor?

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 tools (like FORTRAN or C programs). 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 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.

Can XLRotor compute amplification factors from imbalance response plots?

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. The API Response analysis worksheet will perform this step for you automatically.

Can I choose how I want natural frequencies and damping factors to be output?

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

Can XLRotor compute operating deflected shapes of the entire rotor due to imbalance at a one or more speeds?

Yes. This can be done for either synchronous or asynchronous excitation.

Can XLRotor be used in either English or SI units?

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

Can XLRotor model bearing support stiffness and damping?

Yes. Support mass can also be defined.

Does XLRotor allow me to specify the same peak scale value for all response plots of displacement and/or bearing load?

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 preference. Chart customizations can be done for all projects, or on a project by project basis.

Does XLRotor allow me to choose between peak-to-peak and zero-to-peak for response plots?

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.

Can XLRotor compute static rotor deflection and bearing reactions for offset or mis-aligned bearings?

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

Are example cases included with the program?

Yes. There are over 100 example cases included with the program. Some are published analysis examples found in technical papers and textbooks, and others are of industrial rotors commonly used in the turbomachinery industry.