Motor based condition monitoring
First Claim
1. A method of analyzing operating characteristics of a motor actuated system comprising the steps of:
- sensing a current drawn by a motor to obtain a current waveform;
identifying oscillations in the current waveform caused by segment switching;
determining a number of oscillations corresponding to one rotation of the motor; and
normalizing the current waveform to one rotation of the motor to define a normalized waveform in the spatial domain.
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Abstract
A method of analyzing the condition of a motor driven rotating system using a current waveform produced by the motor. The motor position is initially identified from the current waveform produced by the motor and more particularly, a step of identifying the segment switching of the motor is performed to identify the system position with reference to individual rotations of the motor. The current waveform is then normalized to a preselected number of data points, each rotation being described by the preselected number of data points, such that the current waveform is converted from the time domain to a spatial domain corresponding to positions of the system. Subsequently, a frequency analysis is performed to identify frequencies corresponding to characteristics of the system, including calculating a frequency dependent distribution of the normalized current waveform to determine the energy content of the waveform at particular frequencies.
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Citations
16 Claims
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1. A method of analyzing operating characteristics of a motor actuated system comprising the steps of:
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sensing a current drawn by a motor to obtain a current waveform;
identifying oscillations in the current waveform caused by segment switching;
determining a number of oscillations corresponding to one rotation of the motor; and
normalizing the current waveform to one rotation of the motor to define a normalized waveform in the spatial domain. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of analyzing operating characteristics of a motor actuated system comprising the steps of:
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sensing a current drawn by a motor to obtain a current waveform;
identifying a characteristic in the current waveform corresponding to a predetermined change of position of the motor; and
normalizing the current waveform to the spatial change of position of the motor to define a normalized waveform in the spatial domain. - View Dependent Claims (13, 14, 15, 16)
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Specification