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Connect Ultraprobe 2000 to vbX Instrument

 

QUESTION

How do I connect a UE Systems Ultraprobe 2000 to a vbX instrument and analyze data from it?

ANSWER

This FAQ aims to explain and assist with using, setting up, and analysing the data that is available from the UE Systems Ultraprobe 2000 instrument.



The UE Systems Ultraprobe is an ultrasonic inspection tool that you can use in predictive maintenance. It is capable of detecting frequencies between 20 kHz and 100 kHz. This makes it an excellent tool to be used in conjunction with the Commtest vbTM instrument. The most likely use of this technology would be as an additional analysis tool with the data collector when ultrasonic or bearing frequencies need to be detected and analyzed.

It must be emphasized that the values obtained from the output jack of this device are not scalable. Consequently, they cannot be trended at this time. However, using the powerful analysis capabilities of the vb data collector, both the time waveform and the spectrum can be analyzed, thereby determining the cause of the machine problem.

The output of the Ultraprobe is a heterodyned output, which gives it a similar capability to acceleration high frequency energy spikes that are detected with enveloping. However, there would be little point in using these capabilities as a measurement parameter, because the fault frequency signal has already been processed by the Ultraprobe. The most likely parameter setup would be acceleration. Scaling may have to be log or dB scale if signal levels are extremely low.

Hardware requirements

• Commtest vb instrument
• Ultraprobe 2000
• Cable UE-MP-BNC-2 from UE Systems

Hardware setup

1. Switch on your vb instrument - The main menu displays.
2. Press 0 for Options.
3. Press 5 for Sensor Setup.
4. Press 6 for Change Sensor.
5. Press 4 for Create New Sensor.
6. Choose the settings in the Sensor screen as shown in Figure 1 below.
7. Ensure Drive Current is set to OFF.
8. Store these settings - This will ensure Ultrasonics displays in your Sensors screen, as shown in Figure 2.



Figure 1. Sensor Setup


Figure 2. Sensors Available


Analyzing the Signal

As mentioned earlier, the output of the Ultraprobe is heterodyned and scaled by the user turning a potentiometer. Consequently, there will not be true output sensitivity from this device. However, we are only using it as a high frequency detection tool. Simply think of it as a different sensor and another tool.

The best way to analyze the output of the Ultraprobe is to use the Off-Route (Measure) function on your vb instrument:

  1. Navigate to the vb main menu.
  2. Press 2 for Measure.
  3. Press 6 for Spectrum/Waveform.
  4. Set up a measurement as shown in Figure 3 below.



Figure 3 - Measurement Setup


Note that we have 3200 lines of resolution, with an Fmax of 60 kCPM and an Fmin at 180 CPM. Linear averaging is set at four with a Hanning window.

It must be emphasized that we are now expecting to see bearing-related frequencies without the influence of the lower rotational frequencies.

This is particularly important in situations that exist when a large amount of energy may be created in low speed applications due to looseness, as this is often a characteristic of the machine or the process. This energy may have the effect of masking the sideband information that enables us to analyze and determine bearing and gear-related problems.

Remember that Bearing Fault Frequencies are not pure integer multiples of the rotational frequency, but are mathematically calculated from bearing specification data sheets and software.

Here are some of the advantages of using this method of detection and analysis:

  • You can use the Ultraprobe for a quick look tool for bearing detection, and then use your vb instrument for confirmation.
  • The method is very effective on slow speed machines.
  • Unlike accelerometers, when you use longer probes or stingers you do not lose the signal.
  • The method is extremely sensitive.


Practical use of vb Series instrument and Ultraprobe 2000

Here is an example of a bearing condition on a machine. There are two identical bearings on a shaft running at approximately 1000 RPM.

NOTE: Actual screen captures presented here are for illustration purposes only. They are not from a vb instrument.

Let's first take a look at the good bearing on the right side.

Right side bearing spectrum



Figure 4 - Spectra From Good Bearing


Note the low amplitudes, with maximum of 0.065 gPk. The units are arbitrary. There is some evidence of harmonics at 9000 CPM which probably relates to speed control.

Now let's turn our attention to the other side.

Left side bearing spectrum



Figure 5 - Spectra From Defective Bearing


Here we see maximum amplitude at 2.5gPk with the same gain setting on the Ultraprobe. The non-harmonic bearing frequencies are all evident throughout the spectrum.

Summary

Using this system does not replace any other bearing detection system. It is simply another diagnostic tool that gives positive information about bearing deterioration and failure. Quantitative measurements are possible as long as the gain setting is stored with the data to ensure that comparisons can be made.

Commtest Ascent® software can store the data collected either in the form of screenshots from the vbScreenCapture utility program or in a dynamic format that is either route data or unscheduled data.