Balancing Machine Calibration for Rotor Resonance Correction
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Solution Overview
Problem
Force-measuring balancing machines experience systematic measurement errors when operating near resonance frequencies, limiting their application and accuracy, especially when measuring rotors at higher speeds.
Innovation Solution
The method calculates the natural frequencies of the rotor and bearing system, incorporating these into the permanent calibration to correct measurement errors by adding a frequency response, allowing for higher speed measurements with reduced error.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If permanent calibration is used for force-measuring balancing machines, then measurement speed and productivity are improved, but measurement precision deteriorates when operating near resonance frequencies
Solution Approach 1:
The patent applies dynamics by making the calibration dynamic rather than static. The system calculates natural frequencies of the rotor-bearing system and uses these to dynamically adjust the calibration parameters based on the operating speed. This allows the calibration to adapt to changing resonance conditions, maintaining measurement precision across a wider speed range while preserving the speed advantage of permanent calibration.
Solution Approach 2:
The patent changes the calibration parameters based on the rotor's natural frequencies and operating speed. By calculating the frequency ratio and applying correction factors that depend on these parameters, the system adjusts the calibration to account for resonance effects. This parameter-based correction enables accurate measurements at higher speeds without sacrificing the efficiency of permanent calibration.
2Productivity
If the rotor mass and measurement speed are increased, then productivity and application range are improved, but measurement precision deteriorates due to resonance approximation
Solution Approach 1:
The patent applies preliminary action by calculating the rotor's natural frequencies before performing the imbalance measurement. The system uses these pre-calculated frequencies to determine the frequency ratio and apply appropriate correction factors to the calibration. This preliminary calculation of resonance characteristics allows the system to compensate for resonance effects in advance, enabling accurate measurements with heavier rotors at higher speeds.
Solution Approach 2:
The patent implements feedback by using the calculated natural frequencies and frequency ratio to continuously adjust the calibration parameters. The system monitors the operating conditions and applies correction factors based on the proximity to resonance. This feedback mechanism ensures that measurements remain accurate even when operating parameters change, expanding the safe operating range for heavier rotors.
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 expansion of the application range for hard, force-measuring balancing machines enables rotor measurement at higher speeds with minimal error, requiring only rotor mass and machine parameters, simplifying the process and reducing time expenditure.
Implementation Method 1
The bearing stands 3 are spring-loaded and support the rotor 2
Implementation Method 2
Vibration measuring transducers 8 are mounted on the bearing stands 3
Data Source
Figure 1
AI summary
The method involves calculating the resonant frequencies of the rotor (2) to be balanced, in a translatory direction corresponding to the measuring direction of sensing elements (8) and in a rotational direction about an axis, from the mass of rotor mounted in the balancing machine (1), for computing the co-oscillating mass of the bearing supports (3), the rigidity of the bearing supports and the spacing of the rotor bearings of the bearing supports. The frequency response calculated from the resonant frequencies and the rotor frequency is introduced to the permanent calibration. An independent claim is included for force-measuring balancing machine.