Rotating Shaft Vibration Analysis with Constant Samples Per Revolution
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Solution Overview
Problem
Current machine condition monitoring methods for machines with moving parts, such as motors and pumps, face challenges in accurately analyzing vibrations to predict maintenance needs due to noise interference and varying rotational speeds, leading to potential sudden failures.
Innovation Solution
A system comprising a sensor that generates an analogue electric measurement signal from mechanical vibrations, an analogue-to-digital converter, decimators, and an enhancer that processes the signal to maintain a constant sample rate per revolution, amplifying repetitive signal components over stochastic ones, enabling early detection of incipient damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If vibration measurements are performed manually by an operator using a measuring instrument, then the machine condition can be evaluated, but the process is time-consuming and labor-intensive
Solution Approach 1:
The system enables automatic machine condition monitoring by deploying sensors that continuously collect vibration data and transmit it to a processing system, eliminating the need for manual operator intervention. The system processes and analyzes the data automatically, generating condition assessments without human involvement in the measurement process.
Solution Approach 2:
Manual mechanical measurement processes are replaced with an automated electronic system comprising vibration sensors, analog-to-digital converters, signal processing units, and analysis software. This substitution transforms the mechanical manual measurement approach into an automated electronic monitoring system that operates continuously without human intervention.
2Reliability
If shock pulse measuring is used to detect bearing defects, then early damage detection is possible, but noise interference from varying rotational speeds reduces measurement reliability
Solution Approach 1:
The system dynamically adapts the sampling frequency based on the detected rotational speed of the machine. When rotational speed varies, the sampling frequency is adjusted accordingly to maintain a constant number of samples per revolution, ensuring consistent condition assessment reliability despite speed fluctuations and noise interference.
Solution Approach 2:
The system changes the sampling frequency parameter in response to detected rotational speed variations. By adjusting this parameter dynamically, the system maintains optimal measurement conditions across varying operational speeds, filtering out noise while preserving reliable damage detection capability.
3Device complexity
If the sampling frequency is kept constant regardless of rotational speed variations, then the data processing is simplified, but the number of samples per revolution varies leading to inaccurate condition assessment
Solution Approach 1:
The system implements dynamic sampling frequency adjustment based on detected rotational speed. Rather than using a fixed sampling rate, the system continuously adapts the sampling frequency to maintain consistent samples-per-revolution, improving condition assessment accuracy while adding adaptive control functionality.
Solution Approach 2:
The processing system performs multiple functions: it detects rotational speed, determines appropriate sampling frequencies, converts analog signals to digital, processes the digital signals, and generates condition assessments. This multi-functional approach handles both the complexity of variable speed compensation and the simplicity of unified data processing in a single integrated system.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This system allows for reliable and early detection of machine condition deterioration, even in noisy environments, by maintaining consistent sample rates and amplifying relevant signal patterns, thereby reducing the risk of sudden failures and improving maintenance timing.
Implementation Method 1
a first sensor adapted to generate an analogue electric measurement signal (SEA) dependent on mechanical vibrations emanating from rotation of said part
Data Source
AI summary
A method analyzing a machine having a rotating shaft includes generating an electric measurement signal dependent on mechanical vibrations from the shaft rotation; sampling the measurement signal to generate a digital measurement data signal; performing a decimation of the digital measurement data signal to achieve a digital signal having a reduced sampling frequency, where the decimation includes controlling the reduced sampling frequency such that the number of sample values per revolution of the shaft is kept at a substantially constant value, and receiving the digital signal at an enhancer input performing a correlation in the enhancer so as to produce an output signal sequence where repetitive signals amplitude components are amplified in relation to stochastic signal components, and performing a condition analysis for analyzing the condition of the machine dependent on the digital signal having a reduced sampling frequency.