How to choose the installation position of the piezoelectric acceleration sensor

When setting up an accelerometer, the goal is to ensure it captures the full vibration spectrum. While this ideal scenario is desirable, achieving it depends heavily on how the sensor is mounted. It's important to note that the natural frequency of the accelerometer is influenced by its mass and stiffness. Any installation method that alters these properties can affect the sensor’s performance.

To ensure accurate vibration measurements, follow these key guidelines:

1. The installation should not restrict the useful frequency range or limit the vibration measurement. 2. The added mass of the sensor must not alter the dynamic characteristics of the object being tested. 3. Ensure consistent and repeatable mounting points to allow for reliable and comparable measurements over time.

Now, let’s explore the specific techniques and considerations for installing accelerometers properly.

First, the surface preparation for the installation.

To achieve a higher resonance frequency, the surface where the sensor is mounted should be as clean and smooth as possible. Ideally, it should meet the machining standards shown in Figure 1-1. The threaded holes used for mounting the accelerometer should also conform to the specifications provided in the same figure. If there are any contaminants, they can be removed using solvents like acetone.

Second, the selection of the accelerometer mounting position.

In many cases, the best location for the accelerometer is clear and straightforward. The sensor should be placed so that its primary sensitivity axis aligns with the direction of vibration. This ensures maximum accuracy in capturing the movement.

Choose a location where the path from the vibration source to the sensor is short and rigid. Avoid flexible connections or elements like gaskets that might introduce damping effects. For example, when measuring vibrations in rotating machinery, the bearing housing is typically the most suitable spot for mounting the sensor.

Important vibration data is often found along the axial, horizontal, and vertical directions. Using a three-axis accelerometer or three single-axis sensors with a compatible mounting base allows for simultaneous measurement of vibrations in all three perpendicular directions. In some large equipment, such as heavy machinery, three separate single-axis accelerometers may be installed at the bearing ends to measure X, Y, and Z-axis vibrations accurately.