3.1 Introduction

The topics discussed in the previous sections were theoretical in nature, introducing the basics of vibration. With data acquisition, we take the first steps into the domain of practical vibration analysis. It includes the following main tasks:

• Collection of machinery vibration

• Conversion of the vibration signal to an electrical signal

• Transformation of the electrical signal to its components

• Providing information and documentation related to vibration data.

The above entails the entire hardware of the vibration analysis system or program. It includes transducers, electronic instruments that store and analyze data, the software that assist in vibration analysis, record keeping and documentation.

3.2 Collection of Vibration Signal Vibration Transducers, Characteristics and Mountings

To measure machinery or structural vibration, a transducer or a vibration pickup is used. A transducer is a device that converts one type of energy, such as vibration, into a different type of energy, usually an electric current or voltage.

Commonly used transducers are velocity pickups, accelerometers and Eddy current or proximity probes. Each type of transducer has distinct advantages for certain applications, but they all have limitations as well. No single transducer satisfies all measurement needs. One of the most important considerations for any application is to select the transducer that is best suited for the job.

The various vibration transducers are discussed below.