Fault detection for laminated core
First Claim
1. A method of evaluating the condition of a laminated core of an electric machine, comprising:
- positioning a magnetic flux injection excitation yoke extending between a pair of teeth of the laminated core, the excitation yoke having a pair of arms in engagement with the pair of teeth, and the excitation yoke being wound with an excitation winding for producing a magnetic flux excitation;
supplying power to an electrical circuit defined by the excitation winding to produce a magnetic flux in the excitation yoke and to form a magnetic circuit through the excitation yoke and the laminated core;
measuring a characteristic of the electrical circuit of the excitation winding to identify a fault in the magnetic circuit corresponding to an eddy current between individual laminations in the laminated core; and
wherein measuring the characteristic of the electrical circuit of the excitation winding includes determining a variation in the characteristic in the excitation winding corresponding to the fault in the magnetic circuit relative to a determination of the same characteristic measured in the excitation winding for a magnetic circuit created through the excitation yoke and a portion of the laminated core without a fault.
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Abstract
A method of evaluating the condition of a laminated core of an electric machine including positioning a magnetic flux injection excitation yoke extending between a pair of teeth of the laminated core, and the excitation yoke being wound with an excitation winding defining an electrical circuit for producing a magnetic flux excitation. Power is supplied to an excitation winding wound around the yoke to produce a magnetic flux in the yoke and to form a magnetic circuit through the yoke and the laminated core. A characteristic of the electrical circuit of the excitation winding is measured to identify a fault in the magnetic circuit corresponding to an eddy current between individual laminations in the laminated core.
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Citations
20 Claims
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1. A method of evaluating the condition of a laminated core of an electric machine, comprising:
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positioning a magnetic flux injection excitation yoke extending between a pair of teeth of the laminated core, the excitation yoke having a pair of arms in engagement with the pair of teeth, and the excitation yoke being wound with an excitation winding for producing a magnetic flux excitation; supplying power to an electrical circuit defined by the excitation winding to produce a magnetic flux in the excitation yoke and to form a magnetic circuit through the excitation yoke and the laminated core; measuring a characteristic of the electrical circuit of the excitation winding to identify a fault in the magnetic circuit corresponding to an eddy current between individual laminations in the laminated core; and wherein measuring the characteristic of the electrical circuit of the excitation winding includes determining a variation in the characteristic in the excitation winding corresponding to the fault in the magnetic circuit relative to a determination of the same characteristic measured in the excitation winding for a magnetic circuit created through the excitation yoke and a portion of the laminated core without a fault. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A method of evaluating the condition of a laminated core of an electric machine, comprising:
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positioning a magnetic flux injection excitation yoke extending between a pair of teeth of the laminated core, the excitation yoke having a pair of arms in engagement with the pair of teeth, and the excitation yoke being wound with an excitation winding for producing a magnetic flux excitation; providing a reference element having an impedance that is the same as an impedance of the excitation winding; providing a bridge circuit in which the excitation winding and the reference element are each located in a respective branch of the bridge circuit; supplying power to the excitation winding to produce a magnetic flux in the excitation yoke and to form a magnetic circuit through the excitation yoke and the laminated core, wherein one of a current and a voltage in the branches of the bridge circuit are balanced when the excitation yoke is positioned at a location where there are no faults in the laminated core; and determining an imbalance between the branches of the bridge circuit when at least one of the excitation yoke and the reference element is located adjacent to a fault formed by a short between adjacent laminations in the laminated core. - View Dependent Claims (17, 18, 19, 20)
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Specification