What You’ll Learn 🎯

Configure DewesoftX Orbit Analysis: setup frequency source, RPM, calculation, runout compensation, reference orbit, and machine geometry
Connect and calibrate proximity probes (X/Y) and keyphasor/tacho sensors for journal-bearing orbit measurement
Capture and analyse raw, filtered, averaged orbits, polar and Bode plots, shaft centerline trajectories, waterfalls, and clearance circles
Apply runout compensation to remove shaft irregularities and set reference orbits for comparative analysis

Identify and interpret common rotor faults: imbalance, misalignment, oil whirl, oil whip, resonance effects
Use X-Y plots and polar diagrams to assess bearing lubrication state, rotor dynamics, and clearance behavior
Monitor journal bearing condition over time and across speed ranges (runup, steadystate, coastdown)
Export reports and integrate orbit data with other modules like FFT, Order Tracking, rotor balancing, and historical databases

Course overview

The Orbit Analysis course enables engineers and vibration analysts to master rotor dynamics diagnostics using DewesoftX and compatible DAQ hardware. By measuring the shaft’s motion within journal bearings—via dual proximity probes and a tacho/keyphasor—the course teaches how to visualise rotor orbits as raw, averaged, or filtered plots alongside polar and Bode representations.

You’ll gain practical experience configuring measurement parameters: selecting RPM range, harmonic orders, FFT resolutions, and enabling runout compensation and reference orbits. The course guides you through detecting common fault conditions—such as imbalance, misalignments, subsynchronous vibrations like oil whirl/whip, or resonance—using dedicated widgets like clearance circles and waterfall spectrograms.

Additionally, the training covers real-time monitoring across machine operation phases (runup, steadystate, coastdown), report generation, and integration with other Dewesoft modules like Order Tracking, FFT, rotor balancing, OPC UA, and Historian logging . By the end, attendees are equipped to deploy orbit analysis in R&D or operational environments, enhancing predictive maintenance and reducing downtime in turbomachinery applications.

View the Orbit Analysis webinar

Dewesoft Orbit Analysis overview

Introduction to orbit analysis

Why should you use orbit analysis?

Steady, continuous operation with minimal malfunctions and vibrations is essential for maximizing productivity and ensuring the reliable performance of a machine—whether it is a large rotating mass in a power plant or a high-revving compressor. By understanding rotor movement, various phenomena related to lubrication and bearing conditions can be identified, allowing machine operations to be optimized.

To achieve this, the measurement and analysis of rotational vibration data are crucial. Dewesoft Orbit Analysis is an ideal tool for examining rotor dynamic behavior, assessing any motion restrictions that cause vibration, and preventing potential damage to rotating machinery. Such damage can lead to premature wear of components and, ultimately, critical failure.

Orbit Analysis enables continuous monitoring and evaluation of the current condition of journal bearings and how they have performed over time during operation.

It is specifically designed for these bearing types to inspect and diagnose shaft or journal movement, oil lubrication behavior, and clearance levels.

Dedicated display widgets for orbit analysis help provide a clear overview of the condition of one or multiple bearings. Such analysis is crucial for understanding the impact of lubrication oil, shaft load, rotational speed, clearance, and bearing wear.

When should you use orbit analysis?

Orbit analysis is suitable for the evaluation of journal bearings. These bearings are also sometimes referred to as bushings, plain bearings, or sleeve bearings. All of these types feature a fluid lubrication layer between the shaft and the bearing, allowing the shaft to slide with some freedom of movement within the clearance.

Orbit analysis is not applicable to roller bearings, gears, or other bearing types that involve rolling action or a direct connection between the shaft and the bearing. This is because there is no fluid medium or lubrication layer between the components, and therefore no loose shaft movement. Instead, for such direct-contact bearings and gears, Order analysis is the appropriate method of evaluation.

What is needed to configure and get going with orbit analysis?

The basic measurement setup for orbit analysis consists of the following:

pair of proximity probes (also called eddy-current probes) per bearing,
a keyphasor (3rd proximity probe or a tacho sensor),
a data acquisition system,
orbit analysis software,
and a computer.

By detecting shaft proximity in two directions (X and Y), rotor movement can be calculated and displayed throughout the measurement.

Orbit analysis setup - frequency channel setup

The Orbit Analysis module can be added to a setup by clicking the “+ More” button, where various application modules are available.

When the module is added, the following setup screen appears:

Frequency channel setup
RPM setup
Calculation setup
Runout compensation
Reference orbit
Machine configuration

Frequency channel setup

To determine engine rotation speed, a frequency source must be configured. For Orbit Analysis, a third proximity probe—also called a keyphasor—is most commonly used, as it detects a flat or wedged section on the shaft. This detection generates the necessary pulse per revolution, from which the operating speed is determined.

To provide flexible configuration options, the Orbit Analysis module supports several different sensor types that can be selected as the frequency source:

Counters

For Orbit Analysis, multiple pulses or transient spikes per revolution are often used. This means that a Tacho (digital) input is typically selected for such applications when using sensors that are connected and configured as counters.

To support a wide range of configuration options, various additional counter sensors are available in the dropdown menu, including multiple encoders and CDM sensors. In addition, different filter settings can be applied to the selected frequency source signals.

Counter math

With the Counter Math module, it is possible to determine and recalculate counter angle and frequency outputs both during live measurements (online) and during data file analysis after the measurement (offline).

This can be useful, for example, when correcting a faulty counter setting that wasn’t identified during the measurement, or when fine-tuning a setting to see if it produces better results.

Remember to store the “Raw edge separation” and “Raw count” channels during the measurements, since such data is required to perform the recalculation.

Counter Math supports features such as frequency smoothing, tooth size adjustment, software filtering, and angle wrapping.

If the results from Counter Math are better for your specific data file, you can use the math output as input for other modules that work with counters, such as Orbit Analysis, Order Tracking, or Torsional Vibration.

Analog pulses

When the frequency source is set to Analog Pulses, an analog time channel must be selected. Various sensors that generate analog pulses are supported.

Tacho(Analog): 1 pulse per revolution using a proximity probe or a similar type of analog sensor
36-2 (Analog) or 60-2 (Analog): sensor with 58 or 34 teeth and two missing teeth

To configure the selected analog sensor, click the three-dot icon to open the Angle Sensor Math setup.

In the Angle Sensor Math setup, additional settings are available for configuring the sensor:

Trigger edge
Trigger level (can also be found automatically by selecting ‘’Find’’),
Retrigger level,
Retrigger time,
Output channel unit (Hz or RPM) and
Averaging
a preview of analog tacho signals and triggers.

The lowest detectable frequency limit can be defined in the user input field. The system will not detect frequencies lower than the specified value.

RPM channel

In addition to analog and digital sensors, any signal or channel that directly represents RPM (e.g., 0–10 V corresponds to 0–4500 RPM) can be used as a frequency source. However, since this option does not contain zero-angle information, phase extraction is not possible.

Orbit analysis setup - RPM setup

In the RPM setup section, the lower and upper RPM limits are defined, along with the Delta RPM width and the test direction.

To configure the analysis according to the test conditions of the specific rotating machinery during measurement—and to capture all necessary data—the RPM setup section includes essential settings related to test direction, operating speed range, and the density of value calculations during the test run.

Direction

Orbit Analysis supports the measurement of various machine operating scenarios. Whether you need to measure only runup, coastdown, or both, the analysis can be easily configured via a dedicated dropdown menu.

Since turbomachinery often operates for extended periods in steady-state conditions between runup and coastdown, selecting Both in the dropdown will automatically add a third operating condition: Steady-State. Each direction generates a dedicated set of channels for displaying measured data, which can be shown either on separate widgets or combined into a single widget for comparison.

The user controls the current state of operation during the measurement via a dedicated dropdown which is automatically put on the predefined display. More information on this control dropdown can be found in the later sections of this manual covering Measurement & Visualization.

Delta RPM

Delta RPM defines the speed change interval at which data is updated during measurement for the speed channel and all Orbit Analysis output channels that include speed-related information. These include: Filtered Orbit (e.g., Orbit H1), Shaft Centerline, Polar Plot, Order Waterfall vs. RPM, and FFT Waterfall vs. RPM.

For example, a delta RPM of 50 will update the channels each time during the runup or coastdown the speed of the machine changes for 50 RPM.

During steady-state operation conditions, the speed of the machine usually varies very little. This means that the delta RPM criterion will not be fulfilled and the update of measured data on affected channels will not be triggered. That is why Orbit Analysis can be also updated on time or both (whichever is true first), More info on how to configure update on time criteria can be found in the following section.

Lower and upper RPM limits

Upper and lower RPM limits define the calculation range and are used to correctly configure the resampling algorithm, depending on the maximum order to be extracted. These limits should be set according to the expected speed range of the machine being measured:

Direction control

This makes it possible to control the Direction setting under Measure for multiple Orbit Analysis modules simultaneously. In setups where multiple Orbit Analysis modules are added and the Direction is set to Both, you can choose to link the direction control across modules, instead of changing the direction for each one individually.

The Mode parameter can be set to either Master or Client. For Client modules, you must select the Master module to which they should be linked.

For example, if module OA1 is the Master and module OA2 is a Client linked to OA1, then these two modules are connected. Any direction change made under Measure in one module will automatically apply to the other as well.

Orbit analysis setup - calculation setup

Harmonic list

Filtered orbit extraction is configured by entering the desired order numbers in the Harmonic List field, separating each entry with a semicolon (;). In the example below, the first, second, and third harmonic orbits are extracted.

Order resolution

The selected order resolution defines the step size in the order waterfall between individual extracted orders. The higher the resolution, the greater the number of lines between the orders.

In an FFT, if the line resolution is 0.5 Hz, the required data window must be 2s. The same is true for the ordered resolution: If the resolution is set to 0,25 orders, 4 revolutions are required for one data block. The higher the required order resolution, the slower the rpm must change.

In an FFT, if the line resolution is 0.5 Hz, the required data window must be 2 seconds. The same principle applies to order resolution: if the resolution is set to 0.25 orders, 4 revolutions are required for one data block. The higher the desired order resolution, the more slowly the RPM must change.

Maximum order to analyze

Depending on the measurement application, the maximum order to be analyzed must be set high enough to capture all relevant orders. If, for example, higher-order components are not required in the analysis, a lower value can be selected from the dropdown. This will reduce the necessary sample rate and decrease the amount of data stored.

The needed sample rate is determined by the Orbit Analysis module using the following formula:Upper RPM limit in [Hz] * max order to analyze *2 (Nyquist)To cover 3600 RPM with 32 set as the highest order to analyze, the needed sample rate would be. 60 * 32 * 2 = 3840 Hz.

By default, 32 is set as the highest order to analyze. As the orbit analysis utilizes parts of order tracking math to calculate the data, this setting needs to be configured also in Options->Settings->Extensions->Order tracking. The system will take the highest of the two settings into account.

Time FFT lines

This setting affects the FFT cascade output. A higher number of lines results in better resolution but also increases CPU load. It supports Auto, predefined values selected from a dropdown, or a user-defined custom number of lines.

Bin update

Bin update defines how the output data for each RPM speed bin is calculated.

Always - When multiple values or spectra belong to the same bin, then the newest bin values will overwrite previous values and the newest values will be used in the output for that bin.
First time - When multiple values or spectra belong to the same bin, then only the first bin values will be used in the output for that bin.
Average - When multiple values or spectra belong to the same bin, then averaging for the values and individual and spectral lines will be performed over all values belonging to that bin.
Maximum - When multiple values or spectra belong to the same bin, then the maximum value for all values and individual spectral lines across all spectra belonging to that bin will be kept.

FFT window

Different windows are available for the FFT:

Rectangular,
Hanning,
Hamming,
Flat top,
Triangle,
Blackman (selected by default),
Exponential down and
Blackman - Harris.

Amplitude

Depending on the selected amplitude in the dropdown, the following scaling is applied to the Bode and Polar plots: Peak, RMS, and Peak-to-Peak.

Frequency axis unit

The frequency axis unit for the FFT Waterfall vs. RPM can be selected from the dropdown list.

Using CPM (cycles per minute) instead of RPM (revolutions per minute) for naming the units prevents confusion when showing FFT waterfall vs. RPM on the 3D graph. In this case, CPM is used on the frequency axis and RPM on the speed axis.

Separate spectra per direction

Enabling Separate Spectra per Direction will create the selected spectral channels under each direction’s channel group. When disabled, the spectral results are combined across all directions.

Update interval

The update interval defines the criteria by which data—such as speed, shaft centerline, and polar plots—are updated during the measurement.

There are two different criteria for updating the data:

On RPM change (Delta RPM) - data is updated each time a defined Delta RPM value is exceeded. This is usually selected if the measurement consists of runup or coastdown or both.
On time - Values are updated on a defined time interval, regardless of the Delta RPM specified. This update criterion is suitable for steady-state operating conditions when RPM change criteria are not going to be triggered. Both update criteria can be selected at the same time to appropriately cover different operating conditions.

A measured turbine is going to do a runup from 50 RPM to 4500 RPM, perform a steady state operation at maximum speed for hours and finish with a coastdown back to idle speed. The user inputs 50 as delta RPM, meaning data will be updated in 50 RPM intervals during runup and coastdown. During the steady state machine is running stable and the speed varies very little(+-10RPM) so Update on time is switched on as well and 10 minutes is defined as update time criteria. During hours of steady state operation, values are updated each 10 minutes, resulting in a good overview of the operation.

Orbit analysis waterfalls

The Orbit Analysis module supports Order Waterfall spectrograms versus RPM and versus time, as well as FFT Waterfall versus RPM.

These can be easily enabled by ticking the checkbox in the Ch. Setup section. The results are displayed using the 3D Graph widget, which is further explained in the Measurement & Visualisation section.

Spectra versus RPM can be created as either single-sided or two-sided. Single-sided spectra have an order or frequency axis starting from 0, while two-sided spectra have an axis centered around 0.

Two-sided spectra are particularly useful when analyzing the phase difference between X and Y bearing sensors.

Overall vs. RPM

Overall vs. RPM results are 2D arrays showing overall displacement levels across the defined RPM speed range. These results provide a clear overview and can be useful for documenting critical speed intervals that should be avoided.

Orbit analysis setup - machine configuration

Any number of bearings can be defined within the machine train using Dewesoft OA. The machine configuration setup can then be further divided into subsections:

1 - Quick settings
2 - DC gap
3 - Bearing setup

Quick settings

Under the Channel section, the appropriate input channels must be assigned as X and Y probes for each individual bearing.

Next, configure the angles and positions at which the probes are mounted.

To make the configuration of the Angle and position easier, the graphical representation is available upon entering the Bearing setup

DC gap

Most of the time when proximity probes are mounted, there will be a certain DC component present. Dewesoft Orbit Analysis supports easy measurement of the DC gap by clicking on the Measure button next to the individual probe.

To simplify the configuration of angle and position, a graphical representation becomes available when entering the Bearing Setup.

Bearing setup

Upon selecting Setup under Machine Configuration, a dedicated Bearing Setup window opens, containing all the advanced options for configuring the bearing settings:

sensor configuration,
subsynchronous orbit extraction,
shaft and clearance circle configuration,
average orbit definition, and
DC gap manual input.

Within this setup window, the user defines both the runout compensation and the reference orbit.

Bearing properties

Under Bearing Name, the user can enter a unique name to easily identify the corresponding component.

Sensor

The graphical representation of the shaft—along with direction and angle—helps ensure the correct configuration of sensor settings.

In this section, the user selects the configuration:

Pair is selected when two probes per bearing are used and
Mono in case only one is used.

In addition to selecting the configuration, the correct probe channels must be assigned to the Y and X positions, and their angle and direction must also be set.

The same applies to the Keyphasor under the Tacho angle setting.

Dewesoft Orbit Analysis supports the extraction of subsynchronous orbits, which can be used to detect fluid-induced instabilities such as whirl and whip. The calculation of the subsynchronous orbit is enabled via a dedicated checkbox, and the tracking filter bandwidth is defined in the corresponding input field:

Runout compensation

Runout compensation is necessary whenever shaft shape irregularities are present, as they could be misinterpreted as actual movement during measurement. Dewesoft OA supports multiple methods for establishing runout compensation:

1.) Paste - allows the user to paste values for runout compensation from previous measurements. The angle step needs to be defined the same in the Ch. setup as it was for the data that will be pasted and the data structure of the columns needs to be as stated below in the Import paragraph.

2.) Import - allows import of .txt files containing the runout compensation data. The data structure is important as it needs to contain an angle in the first column, a Y value in the second, and X in the third. A good way to achieve correct structure is to input it in separate columns in Microsoft Excel and then save it as a .txt file. Example .txt file is seen below:

3.) Measure - The last and perhaps most important way of determining the runout compensation is to measure it directly with Dewesoft. This is also the easiest way of doing it as it requires a single click operation in Measure and calculated values are automatically stored in the Ch. setup.

Shaft

This section of the channel setup is dedicated to configuring shaft-related settings. The direction of shaft rotation is selected from the Rotation dropdown menu. The dropdown allows the user to choose between CW (clockwise) and CCW (counterclockwise) rotation.

The Position dropdown defines the shaft's starting position relative to the bearing diameter.

Clearance

Dewesoft Orbit Analysis allows for straightforward definition of the clearance circle under the Clearance section of the Machine Configuration Setup.

Users can choose between circular and elliptical shapes for the clearance area and use the input fields to enter the radius (for a circle) or width and height (for an ellipse).

Average orbit

The average orbit can be configured to display more than a single revolution at a time. This is defined by the value entered in the Periods field—e.g., setting it to 5 means the average orbit will display 5 revolutions.

The user also defines how many revolutions to average by entering the desired number in the Averages input field.

DC gap

In addition to measuring and automatically compensating for the DC gap, Dewesoft Orbit Analysis also allows users to manually enter DC gap values.

This is especially useful for large turbines, such as those found in power plants, where completely static conditions (0 RPM) are rarely achieved. In such cases, the DC gap is measured during probe installation and manually entered for use in later measurements.

Orbit analysis output channels

The Orbit Analysis module includes a wide variety of result types, many of which generate multiple output channels. A complete list of these results—along with brief descriptions, the number of channels created per type, and the recommended display widgets for visualization—is provided in the table below:

Function type	Description	Number of channels	Display widget
Orbit [X] X	[X] order orbit showing displacement in two directions	Per bearing, per order	Orbit plot
r[X]+	Positive-sided component of [X] order	Per bearing, per order	Digital meter
r[X]-	Negative sided component of [X] order	Per bearing, per order	Digital meter
G[X]	[X] order orbit ellipse semi-major axis, a	Per bearing, per order	Digital meter
K[X]	[X] order orbit ellipse semi-minor axis, b	Per bearing, per order	Digital meter
Shaft center	Bearing shaft center displacement	Per bearing, per direction	Orbit plot
Raw orbit	Orbit with all orders over time	Per bearing	Recorder, scope
Bearing [X] Raw orbit	Orbit with all orders over time, with angle info for bearing [X]	Per bearing	Orbit plot
Average orbit	Orbit with all orders averaged over a number of blocks	Per bearing	Orbit plot, 2D graph
Bearing [X] waveform	Waveform with all orders of probe X or Y over time or revolutions	Per bearing, per probe	Orbit waveform
Subsynchronous orbit	Oil whirl/whip orbit	Per bearing	Orbit plot
Subsynchronous order	Oil whirl/whip variable fractional order number	Per bearing	Digital meter
DC gap	Probe DC gap over time	Per bearing, per probe	Digital meter
Time [X]X	[X] order data over time	Per bearing, per probe, per order	Recorder, digital meter
Polar [X]X	[X] order data with RPM stamps	Per bearing, per direction, per probe, and per order	Polar plot
Order waterfall vs. speed [two-sided]	Two-sided order spectra across the RPM speed range	Per bearing, per direction*, and per probe	3D graph
Order waterfall vs. time [two-sided]	Two-sided order spectra over time	Per bearing, per direction*, and per probe	2D graph, 3D graph
FFT waterfall vs. speed [two-sided]	Two-sided FFT spectra across the RPM speed range	Per bearing, per direction*, and per probe	3D graph
Order waterfall vs. speed	Order spectra across the RPM speed range	Per bearing, per direction*, and per probe	3D graph
FFT waterfall vs. speed	FFT spectra across the RPM speed range	Per bearing, per direction*, and per probe	3D graph
Bode plot [X]X	[X] order bode showing magnitude and phase vs. RPM speed	Per bearing, per direction*, and per probe	2D graph
Overall RMS	Total RMS value across the RPM speed range	Per bearing, per direction*, and per probe	2D graph
Overall peak	Total peak value across the RPM speed range	Per bearing, per direction*, and per probe	2D graph
Overall peal-peak	Total pk-pk value across the RPM speed range	Per bearing, per direction*, and per probe	2D graph
SPP Average orbit SPPy	Average orbit longest y direction pk-pk displacement	Per bearing	Digital meter
SPP Average orbit SPPx	Average orbit longest x direction pk-pk displacement	Per bearing	Digital meter
SPP Average orbit SPPmax	Average orbit longest overall pk-pk displacement	Per bearing	Digital meter
SPP Raw orbit SPPy	Raw orbit longest y direction pk-pk displacement	Per bearing	Recorder, digital meter
SPP Raw orbit SPPx	Raw orbit longest x direction pk-pk displacement	Per bearing	Recorder, digital meter
SPP Raw orbit SPPmax	Raw orbit longest overall pk-pk displacement	Per bearing	Recorder, digital meter
SPP orbit [X]X SPPy	[X] order orbit longest y direction pk-pk displacement	Per bearing, per order	Digital meter
SPP orbit [X]X SPPx	[X] order orbit longest x direction pk-pk displacement	Per bearing, per order	Digital meter
SPP orbit [X]X SPPmax	[X] order orbit longest overall pk-pk displacement	Per bearing, per order	Digital meter
Speed	Speed RPM for the OA instance	1	Digital meter
Direction	Test direction for the OA instance	1	Input control, Discrete display

per direction* - is a user-selectable option with the checkbox "Separate spectra per direction".O

Visualization - orbit plot

Each bearing with assigned channels added to the machine train will automatically generate a dedicated predefined display. This display includes a set of Orbit plots, Polar plots, and 2D graphs, as well as a digital meter for speed and an input control dropdown for selecting different operating conditions—if Both is selected under the RPM setup.

Orbit plot

The Orbit Plot is a dedicated widget for the Orbit Analysis module. It displays data from two time-domain channels, creating a two-dimensional visual representation of the motion of a rotating shaft.

The widget graphically shows the position of the proximity probes, along with the tacho (keyphasor) position and the direction of rotation.

Various output channels available in the Orbit Analysis module can be displayed on the Orbit Plot:

Raw orbit,
Average orbit,
Filtered orbit (e.g. Orbit H1, Orbit H1, …),
Subsynchronous orbit and
Shaft centerline

When the Orbit Plot widget is selected, a settings tab appears on the left side of the Measure display, allowing the user to configure the axis.

Number of ticks - changing the number of ticks will increase them on the Orbit plot accordingly. The left picture below shows 5 ticks and the right picture shows 15 ticks:

Auto scale - ticking the checkbox will automatically scale the axes of the Orbit plot. There are two different Auto scale types: Absolute and Relative.

Absolute auto-scale always keeps the zero in the center of the plot and therefore gives a better indication of orbit size and position relative to the center of the bearing:

Relative auto-scale sizes the axes according to the maximum current dimension of the measured orbit. This makes the orbit shape easier to observe and acts as a sort of zoom. The zero in this case is not always in the center position:

Single axis - this checkbox determines the behavior of how channel names are shown next to the orbit plot when showing multiple channels on the same graph. In the below example, two harmonic orbits are shown on the same orbit plot. The left image shows a single axis switched on and the right image shows a single axis switched off:

In addition to axis configuration, various Drawing Options are available when the Orbit Plot widget is selected:

Graph type - The user can select either Grid or Circle. The difference between the two graph types is shown below - the left image shows a Grid and the right image shows a Circle:

When Circle is selected as Graph type, only Absolute auto scale will be available.

The selected Graph type is applied to all of the Orbit plots in the individual display in order to unify the visual representation of the particular display.

Display type - The user has the option to select either RPM or Time (in seconds) to be displayed when the Shaft center is assigned to the Orbit plot. The below images show the difference, the left image displays RPM and the right image displays Time together with the shaft center points:

Time Display type shows relative time - elapsed time since the beginning of the measurement

The images below illustrate the relationship between the probe locations and the shaft position. The Orbit Plot widget demonstrates how four different positions are plotted. In Location 1, the black shaft is farther from the proximity probes than in Location 3:

In the picture below, six orbit plots are shown for six different bearings. This helps illustrate the relationship between keyphasor dot positions across bearing locations, and in turn, provides a better understanding of the rotor shaft's deflection shape.

Recalculation of stored data

Orbit analysis can be recalculated using the raw signals from the proximity probes and the frequency source that were stored during the measurement. To recalculate the data, simply open the data file containing the raw signals and, in Analyze mode, navigate to Offline Math:

1. When in Setup, add the Orbit Analysis by selecting More… and choosing Orbit Analysis from the list of modules:

2. Having added the Orbit Analysis module, configure it by following the same steps described in the previous sections.

3. Return to Review and select Recalculate

4. The recalculated output channels are now displayed on the predefined display.

Recalculation of stored data

Recalculating runout correction

Along with all output channels from Orbit Analysis, runout compensation can also be recalculated during post-processing using the raw data from the proximity probes.

To recalculate and apply runout compensation in Analyze mode, follow the steps below:

1. Navigate to the Runout compensation sub-display template.

2. In the Runout compensation display, place the two cursors over the section of raw data you wish to use for the runout compensation and lock them.

3. Click on Recalculate to determine the runout compensation data:

If you see the Offline Math button instead of the Recalculate button, first set the Orbit Analysis module to Offline under Setup.

4. After Recalculation, the calculated values are automatically added to the setup and can be seen under the Machine configuration - Bearing Setup page:

Make sure to save the setup after measuring the runout compensation in order to be able to simply load and have it ready the next time you use the setup

Recalculating reference orbit

Using the acquired raw data, it is also possible to define the reference orbit in Analyze mode. To recalculate and store the reference orbit in Analyze mode, follow the steps below:

1. Navigate to the pre-defined Reference orbit sub-display template:

2. Place the two cursors over the desired region from which you wish to acquire data to define the Reference orbit, and then lock the cursors:

3. Select Recalculate. If you see an Offline math button instead of the Recalculate button then set the Orbit analysis module to Offline first under Setup.

4. Now the newly calculated Reference orbit data are copied to the clipboard and can be pasted directly into a Reference orbit data table found under the Bearing Setup page.

Machine fault - normal operation

Normal operation is characterized by acceptable vibration levels at all measurement positions. Critical speeds may be excited during speed transients, but the vibration amplitude remains within acceptable limits. Trend plots show consistent amplitude with little or no variation under different loads. The dominant vibration frequency is 1X, with minimal or no vibration at other frequencies.

Amplitude trend

The amplitude trend plot shows a consistent amplitude with no significant dependence on load or time.

1X phase trend

The 1X phase trend will display a constant phase value over time.

Waveform

Direct waveform plots show no truncation, no frequencies other than 1X, and no spikes.

Spectrum

The half-spectrum plot shows a single dominant peak at the 1X frequency, with no significant vibration at other frequencies.

Full spectrum / Two-sided spectrum

The full-spectrum plot shows a single dominant positive peak at the +1X frequency, with no significant vibration at other frequencies. The peak at –1X is lower than the peak at +1X.

Direct orbit

A circular or slightly elliptical orbit with no evidence of truncation or loops is observed. The phase trigger indicates forward precession.

Shaft centerline

The shaft centerline plot shows a normal path from zero to full speed, with no sudden changes. Eccentricity remains below the vertical centerline at full speed.

Bode plot amplitude

The Bode plot (amplitude) shows acceptable amplitude at the critical speed. Some variation between startup and coastdown responses is typical.

Bode plot - phase

The Bode plot (phase) shows a smooth phase shift across the typical speed range, with the rate of change matching previous runup or coastdown events. The phase at both full speed and very low speed remains consistent between events.

Polar plot

The polar plot shows similar amplitude at low speed, through the critical speed, and at full speed across transient events, with acceptable maximum amplitudes at both the critical speed and full speed.

Waterfall

The waterfall plot shows a fairly constant amplitude across multiple periods, with no significant variation in the 1X amplitude.

Other operational symptoms

Bearing temperature trends remain constant with changes in speed and load, staying below alarm limits. Audible noise near the machine shows no changes compared to previous surveys and no signs of abnormal rattling.

Machine fault - mechanical imbalance (blade loss)

A sudden imbalance may be caused by blade loss, the loss of a balance weight, or another component that is normally attached to the rotor. This may occur during normal operation or during a load or speed transient. It can be distinguished from an electrically induced imbalance because the changes in vibration characteristics (amplitude/phase) are not reversible by altering the load or speed.