Method and apparatus for testing laminated cores of electrical machines
First Claim
1. Apparatus for testing a laminated core of an electrical machine, the apparatus comprising:
- excitation signal generating means, arranged to generate an excitation signal at a first frequency which is higher than the rated operating frequency of said electrical machine, for supply to an excitation winding coupled to the laminated core of the electrical machine; and
a phase sensitive detector arranged to receive a first, reference signal having a reference phase and to receive from the laminated core of the electrical machine a second, test signal having a test amplitude and phase, each in response to the excitation signal applied to the excitation winding, the phase sensitive detector being arranged to resolve the test signal into a plurality of components relative to said reference phase of said reference signal and to generate an output signal, the level of said output signal being indicative of the severity of a fault between the laminations of said laminated core.
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Abstract
There is provided an apparatus and associated method for the testing of a laminated core (100) for an electrical machine. The apparatus supplies an excitation signal to the winding (102) of the electrical machine which is of a frequency higher than the rated operating frequency of the machine. There is also provided a phase sensitive detector (110) which receives, from the laminated core (100), a signal in response to the excitation signal. The phase sensitive detector (110) resolves the received signal into a number of components. These components are resolved relative to a reference signal. The size of the components determines the severity of any fault that exists within the laminated core (100.
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Citations
32 Claims
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1. Apparatus for testing a laminated core of an electrical machine, the apparatus comprising:
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excitation signal generating means, arranged to generate an excitation signal at a first frequency which is higher than the rated operating frequency of said electrical machine, for supply to an excitation winding coupled to the laminated core of the electrical machine; and
a phase sensitive detector arranged to receive a first, reference signal having a reference phase and to receive from the laminated core of the electrical machine a second, test signal having a test amplitude and phase, each in response to the excitation signal applied to the excitation winding, the phase sensitive detector being arranged to resolve the test signal into a plurality of components relative to said reference phase of said reference signal and to generate an output signal, the level of said output signal being indicative of the severity of a fault between the laminations of said laminated core. - View Dependent Claims (2, 3, 4, 9, 11, 13, 14, 15, 16, 17, 18, 19)
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5. Apparatus for testing a laminated core of an electrical machine, the apparatus comprising:
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excitation signal generating means, arranged to generate an excitation signal at a first frequency which is higher than the rated operating frequency of said electrical machine, for supply to an excitation winding coupled to the laminated core of the electrical machine;
a phase sensitive detector arranged to-receive a first, reference signal having a reference phase and to receive from the laminated core of the electrical machine a second, test signal having a test amplitude and phase, each in response to the excitation signal applied to the excitation winding, the phase sensitive detector being arranged to resolve the test signal into a plurality of components relative to said reference phase of said reference signal and to generate an output signal, the level of said output signal being indicative of the severity of a fault between the laminations of said laminated core; and
a frequency generator, arranged to generate at least one further excitation signal having a respective frequency that is higher than the rated operating frequency of said electrical machine. - View Dependent Claims (6, 7, 8, 10, 12)
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20. A method for testing a laminated core of an electrical machine, comprising the steps of:
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generating an excitation signal at a first frequency, wherein the first frequency is higher than the rated operating frequency of said electrical machine;
receiving a first, reference signal having a reference phase and a second, test signal having a test amplitude and phase, each signal generated in response to the excitation signal applied to the excitation winding;
resolving the test signal into a plurality of components with respect to the reference phase of the reference signal; and
generating an output signal, the level of said output signal being indicative of the severity of a fault between the laminations of said laminated core. - View Dependent Claims (21, 22, 23, 28, 30, 32)
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24. A method for testing a laminated core of an electrical machine, comprising:
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generating an excitation signal at a first frequency, wherein the first frequency is higher than the rated operating frequency of said electrical machine;
receiving a first, reference signal having a reference phase and a second, test signal having a test amplitude and phase, each signal generated in response to the excitation signal applied to the excitation winding;
resolving the test signal into a plurality of components with respect to the reference phase of the reference signal;
generating an output signal, the level of said output signal being indicative of the severity of a fault between the laminations of said laminated core; and
generating at least one further excitation signal, having a respective frequency that is higher than the rated operating frequency of said electrical machine. - View Dependent Claims (25, 26, 27, 29, 31)
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Specification