Electric winding displacement detection method and apparatus
First Claim
1. A diagnostic device for generating a characteristic impedance for an electrical winding having an input terminal and an output terminal, comprising:
- a signal generator for applying an electrical signal having a frequency component to the input terminal of the electrical winding;
sensing means for detecting a magnitude and a phase of an output electrical signal at the output terminal of the electrical winding, the sensing means converting the magnitude and the phase of the output electrical signal into digital signals;
a processing means for setting parameters of the electrical signal and for receiving the digital signals, the processing means calculating the characteristic impedance with the digital signals and the parameters of the electrical signals corresponding to one frequency, based on a transmission line model of the electrical winding; and
storage means for storing the digital signals and the parameters of the electrical signal.
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Abstract
A method and system for obtaining the characteristic impedance of an electrical winding by measuring the input and output voltages and the currents within a winding across a low frequency range, and applying transmission line properties to model the winding. The characteristic impedance (Zc) is directly proportional to the capacitance of the winding, and is independent of external circuits. Thus any changes to Zc will reflect movements of the winding that would affect the capacitance. Because Zc has a smooth and robust monotonical relationship with frequency of the applied signal, the resulting curve is exponential in shape. A relative comparison between Zc curves will provide a clear indication of the overall axial or radial winding movements, or winding faults, which can be used to assess the overall health of the winding.
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Citations
35 Claims
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1. A diagnostic device for generating a characteristic impedance for an electrical winding having an input terminal and an output terminal, comprising:
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a signal generator for applying an electrical signal having a frequency component to the input terminal of the electrical winding; sensing means for detecting a magnitude and a phase of an output electrical signal at the output terminal of the electrical winding, the sensing means converting the magnitude and the phase of the output electrical signal into digital signals; a processing means for setting parameters of the electrical signal and for receiving the digital signals, the processing means calculating the characteristic impedance with the digital signals and the parameters of the electrical signals corresponding to one frequency, based on a transmission line model of the electrical winding; and storage means for storing the digital signals and the parameters of the electrical signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A method for determining a characteristic impedance of an electrical winding, comprising:
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applying an input signal having a frequency component to a first terminal of the electrical winding; measuring an output signal at a second terminal of the electrical winding; storing the input signal data and the output signal data; and calculating the characteristic impedance based on a transmission line model of the electrical winding with the input signal data and the output signal data corresponding to one frequency. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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29. A method for assessing a condition of an electrical winding, comprising:
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obtaining a base characteristic impedance of the electrical winding at a first time; storing the base characteristic impedance corresponding to the first time; obtaining a current characteristic impedance of the electrical winding at a second time after the first time; storing the current characteristic impedance corresponding to the second time; calculating a difference value between the current characteristic impedance and the base characteristic impedance; and calculating an approximate winding displacement from the difference value. - View Dependent Claims (30, 31, 32, 33, 34, 35)
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Specification