Drive Shaft Break Detection Using Fixed-Ratio Pulse Comparison
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Solution Overview
Problem
Existing drive shaft train monitoring systems often misinterpret shaft breakage due to directional changes, vibrations, or incomplete signal pulses from sensors with varying resolutions, leading to false error detection and potential system unavailability.
Innovation Solution
A circuit arrangement that uses high-resolution sensors at the drive end and lower-resolution sensors at the output end, generating pulse trains with a fixed frequency ratio, and comparing counter readings to determine shaft breakage, ensuring accurate detection of rotational speed, angle, and direction while avoiding misinterpretations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a second sensor with lower measurement resolution is used at the output end for shaft break detection, then the device complexity is reduced and cost is lowered, but false shaft break signals are generated during directional changes and vibrations
Solution Approach 1:
A pulse generator is introduced as an intermediary component that receives pulses from the low-resolution sensor and transforms them into a standardized pulse train with fixed frequency ratio. This mediator bridges the gap between the limited-capability sensor and the requirements for accurate shaft break detection, converting irregular pulses into reliable detection signals.
Solution Approach 2:
The system changes the parameter of pulse frequency by using a pulse generator that outputs pulses at a fixed frequency ratio relative to the first sensor, regardless of the irregular intervals from the second sensor. This parameter transformation allows the low-resolution sensor data to be processed as if it came from a high-resolution sensor, eliminating false detections during directional changes and vibrations.
2Measurement precision
If pulse trains with fixed frequency ratio are generated and counter readings are compared, then shaft break detection accuracy is improved, but the device complexity increases due to additional circuit components
Solution Approach 1:
The pulse generator serves multiple functions: it receives pulses from the second sensor, generates standardized pulse trains with fixed frequency ratio, and provides these pulses to the evaluation circuit. This multi-functional component reduces the need for separate processing circuits for each sensor, thereby limiting the increase in overall device complexity while maintaining high detection accuracy.
Solution Approach 2:
The evaluation circuit continuously compares counter readings from both sensors and provides feedback to detect discrepancies indicating shaft breakage. This feedback mechanism enables accurate real-time detection without requiring complex predictive algorithms, maintaining simplicity while improving precision.
3Measurement precision
If only high-resolution sensor signals are used for shaft break detection, then measurement precision is maintained, but the system cannot determine rotational speed, angle, and direction using a single sensor
Solution Approach 1:
The measurement tasks are segmented between two sensors: the first high-resolution sensor handles precise position and direction detection, while the second lower-resolution sensor handles rotational speed measurement. The pulse generator and evaluation circuit integrate these segmented measurements, allowing the system to determine rotational speed, angle, and direction using both sensors working in complementary roles.
Data Source
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AI summary
The method involves generating a primary pulse train with the drive end, and generating a secondary pulse train with the output end. The pulse frequency ratio between the two pulse trains is formed according to the demand. The pulse of the primary pulse train during a time window (t-m) in a counter (10) is accumulated. The counter readings of the two counters (20) are compared. An independent claim is also included for a circuit arrangement for detecting the failure of a drive shaft train between a drive end and an output end.