What Is a Portable Vibration Meter?
Portable vibration meters are portable vibration meters that perform vibration measurement and vibration analysis of machinery.
They are compact and lightweight and feature a panel and buttons for easy and convenient measurement. This makes it easy to use immediately on site. Vibration is a major factor in causing structures and machinery to break or stop abnormally. With portable vibration meters, vibration measurement and analysis can be easily performed without the need for advanced technology.
Uses of Portable Vibration Meters
Figure 1. Vibration measurement of a three-phase motor using a portable vibrometer
Portable vibration meters are used to inspect industrial machinery such as three-phase motors and for product inspection and testing on product lines.
Vibrometers may be directly attached to equipment for constant monitoring, or they may be installed stationary in shipping or transportation environments for inspection or R&D. Portable vibration meters are specialized for portability and are used in patrol monitoring, inspection, and maintenance.
Principle of Portable Vibration Meters
There are two main measures of vibration: “frequency” and “amplitude,” and the vibration is measured by processing these measurements.
- Frequency (ESP. Of Waveforms): The frequency at which the vibration is occurring
- Amplitude (Of Vibration): The magnitude of the vibration swing
To perform the measurement process, vibrations are first measured at a fixed sampling period and converted from these values into an electrical signal. In most cases, this electrical signal is amplified by an amplifier and processed to a value that is easily measured by an A/D converter.
Using these vibration values, a filtering process is applied to remove noise and measure the exact level of vibration. This gives us the frequency and amplitude at which the object is vibrating.
FFT analysis is often used to measure machinery that is experiencing abnormal vibration.
These processes are then visualized by means of waveform graphs and numerical values, converted into easily recognizable values, and displayed on a monitor. Portable vibration meters are small but retain multiple functions, such as efficiently displaying numerical values on a monitor screen and transferring data to a PC via a Wi-Fi connection or SD card.
Types of Portable Vibration Meters
There are two main types of portable vibration meters: contact and non-contact.
1. Contact Type Portable Vibration Meter
Figure 2. Contact-type portable vibrometer
A contact-type portable vibration meter, such as the one shown in Figure 2, is equipped with an accelerometer. The accelerometer is attached directly to the machine and measures its vibration. The advantage of contact-type portable vibration meters is that they are relatively inexpensive and compact.
2. Non-Contact Type Portable Vibration Meter
Figure 3. Portable vibrometer of non-contact type
A laser Doppler vibrometer is often used as a non-contact type portable vibration meter. A laser beam is irradiated onto an object, and the Doppler effect of the light is used to measure the vibration of the object.
The advantage of the non-contact type portable vibration meter is that it can measure vibrations without contact, making it possible to measure rotating objects such as motor shafts.