Correct Vibration Sensor Installation: 3-Axis (XYZ) vs. Single-Axis

In successful vibration monitoring, the "installation direction" and "mounting method" of the sensor are the most critical factors that determine data reliability. No matter how highly accurate the sensor is, if the installation method is incorrect, you will not be able to capture the necessary anomaly signals.

This article explains the basics of how vibration propagates (in 3 axes) in rotating machinery such as motors and pumps, and the advantages of simultaneous 3-axis detection using the wireless vibration sensor "conanair". If you would like to first understand the mechanism and overall picture of predictive maintenance, please also see For Beginners in Predictive Maintenance | Conanair Setup Guide & Vibration Basics.

The Meaning of the Three Directions (X, Y, Z Axes) in Vibration Measurement

Depending on the type of anomaly in rotating machinery, the direction in which the vibration appears most strongly differs. The relationship between the three directions measured by conanair and general single-axis measurements is as follows.

• conanair X-Axis: Axial Direction
• conanair Y-Axis: Circumferential Direction
  Please note that this differs from horizontal measurement in a single-axis vibration meter.
• conanair Z-Axis: Radial Direction
  Measuring vibration in the radial direction is fundamental for bearing diagnosis. In single-axis measurement, both horizontal (Horizontal) and vertical (Vertical) measurements often measure the radial direction.

* [Note]
conanair's 3-axis synthesized vibration value (3D) is simple and easy to use as an index for trend management because you do not have to worry about the sensor's installation direction. However, caution is required because when the vibration values in the axial or circumferential directions are large, changes in radial vibration can become difficult to notice.
For trend management, monitoring changes in the vibration value in the radial direction of the rotation axis is often effective.

The Decisive Difference Between Simultaneous 3-Axis Measurement (conanair) and Single-Axis Measurement (Pencil Type)

There is a decisive difference in operation and data quality between the "single-axis pencil-type vibration meter" easily used in the field and the "3-axis wireless vibration sensor (conanair)" permanently installed on the machine.

While the pencil type is convenient for quickly finding out "roughly how much it is shaking right now," for "trend management of minute changes"—the cornerstone of predictive maintenance—a permanently installed type like conanair, which can conduct fixed-point observation of 3 axes simultaneously under the exact same conditions, is overwhelmingly advantageous.

[Important] Sensor Mounting Methods and High-Frequency Characteristics (Field Know-How)

Just as important as the installation direction is how the sensor is fixed to the machine. Especially when measuring the "high-frequency range (acceleration)" that indicates early-stage bearing anomalies, the mounting method directly affects the sensor's sensitivity (frequency response).

The following formula is a basic model showing the relationship between the resonant frequency ( $f_n$ ) caused by the rigidity of the fixed part (spring constant $k$ ) and the mass of the sensor ( $m$ ).

In actual field environments, the following three mounting methods are mainstream. Please select one according to the target machine and the anomaly you want to detect.

• Stud (Screw) Mount [Recommended]
  A screw hole is tapped into the machine side, and the sensor is firmly fixed with a dedicated stud. It provides the highest rigidity and allows the sensor to fully demonstrate its original performance up to the high-frequency band. Essential for precision bearing diagnosis.
• Adhesive / Epoxy Mounting
  The next best option when a screw hole cannot be drilled. If the adhesive layer is thick or a soft adhesive is used, the rigidity decreases, and high-frequency components will be attenuated. The trick is to apply a hardening type of adhesive as thinly as possible.




• Magnet Mounting
  Convenient and easy to attach and detach, but the mounting rigidity is lower compared to screwing or adhesives. Because the magnet itself is prone to resonance, especially in the high-frequency range, this method is better suited for trend management of overall vibration using velocity (mid-to-low frequencies) or simplified diagnosis. For more information on how to properly use metrics such as velocity and acceleration, please also refer to Vibration Data Basics: Displacement, Velocity, Acceleration & Frequency Bands.

conanair is designed to flexibly accommodate these mounting methods according to the real-world situations in the field. To practice correct trend management using Raw Data, always start by "fixing it correctly" in the "correct direction."

The Importance of 3-Axis Data for AI Integration

In recent years, there has been a growing trend to introduce systems that automatically detect anomaly signs using machine learning and AI. If only single-axis data is fed into these models, it is extremely difficult for the AI to distinguish between complex anomaly modes, such as "is this unbalance or misalignment?" Accumulating "simultaneous 3-axis raw data"—which includes the correlation between all X, Y, and Z axes (for example, the vibration ratio between the horizontal and axial directions)—as training data is an essential condition for cultivating highly accurate predictive maintenance AI models.

30-Day Free Trial & Inquiry

Try conanair for free for 30 days. Here is what our users are saying:

• Easy installation for immediate use
• No app required; operate via web browser
• No cloud required for fully automatic measurement
• Affordable, including dedicated software

Try equipment anomaly detection and predictive maintenance for free. Please feel free to contact us.

30-Day Free Trial & Inquiry

Try conanair for free for 30 days. Here is what our users are saying:

• Easy installation for immediate use
• No app required; operate via web browser
• No cloud required for fully automatic measurement
• Affordable, including dedicated software

Try equipment anomaly detection and predictive maintenance for free. Please feel free to contact us.

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