quency sẽ được chỉ định là 4X, hoặc bốn lần tốc độ chạy. Ngoài ra, bởi vì một số trục trặc có xu hướng xảy ra ở tần số cụ thể, nó giúp để phân biệt các lớp học một số trục trặc từ những người khác. Lưu ý, tuy nhiên, mối quan hệ tần số / sự cố không loại trừ lẫn nhau, và một vấn đề cụ thể cơ khí có thể không chắc chắn là do một tần số duy nhất. | 130 An Introduction to Predictive Maintenance quency would be indicated as 4X or four times the running speed. In addition because some malfunctions tend to occur at specific frequencies it helps to segregate certain classes of malfunctions from others. Note however that the frequency malfunction relationship is not mutually exclusive and a specific mechanical problem cannot definitely be attributed to a unique frequency. Although frequency is a very important piece of information with regard to isolating machinery malfunctions it is only one part of the total picture. It is necessary to evaluate all data before arriving at a conclusion. Amplitude Amplitude refers to the maximum value of a motion or vibration. This value can be represented in terms of displacement mils velocity inches per second or acceleration inches per second squared each of which is discussed in more detail in the Maximum Vibration Measurement section that follows. Amplitude can be measured as the sum of all the forces causing vibrations within a piece of machinery broadband as discrete measurements for the individual forces component or for individual user-selected forces narrowband . Broadband component and narrowband are discussed in the Measurement Classifications section that follows. Also discussed in this section are the common curve elements peak-to-peak zero-to-peak and root-mean-square. Maximum Vibration Measurement. The maximum value of a vibration or amplitude is expressed as displacement velocity or acceleration. Most of the microprocessorbased frequency-domain vibration systems will convert the acquired data to the desired form. Because industrial vibration-severity standards are typically expressed in one of these terms it is necessary to have a clear understanding of their relationship. Displacement. Displacement is the actual change in distance or position of an object relative to a reference point and is usually expressed in units of mils inch. For example displacement .
