Fault detection in induction machines
First Claim
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1. A method of detecting a fault in an induction machine having one or more windings, the method comprising:
- detecting a phase component of a driving current flowing in a stator of one or more windings of the induction machine at a supply frequency;
generating a predetermined fault frequency based on a slip of the induction machine, the slip of the induction machine being based on a rotational speed of a rotor of the induction engine relative to a rotational speed of the stator in the induction machine and the supply frequency of the current flowing in the induction machine;
determining whether a respective sideband of one or more selected harmonics of the supply frequency exists at the generated predetermined fault frequency in a signal in the one or more windings, each of the one or more selected harmonics of the supply frequency being a harmonic frequency higher than the supply frequency;
determining that a fault has occurred in the one or more windings of the induction machine in response to determining that the existence of the respective sideband of one or more selected harmonics of the supply frequency is at the generated predetermined fault frequency;
determining whether a power distribution of at least one of the one or more selected harmonics to the respective sidebands is below a predetermined threshold; and
responsive to the power distribution being below the predetermined threshold, determining and identifying a fault type in the induction machine based on identifying fault frequency components of the selected harmonics of the supply frequency, other than the supply frequency itself; and
in response to identifying the fault type in the induction machine, instructing a repair the induction machine based on the identified fault type determined using the fault frequency components of the selected harmonics of the supply frequency, such that the repair eliminates the determined fault, whereby the fault in the induction machine is determined and identified at a lower frequency resolution, a lower slip, and a lower fault severity allowing for earlier and more reliable detection of the fault to prevent permanent failure/damage of the induction machine.
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Abstract
A method of detecting a fault in an induction machine having one or more windings arranged to draw current at a supply frequency, the method including: performing a process of judging whether a respective sideband of one or more selected harmonics of the supply frequency exists at a predetermined fault frequency in a signal in the one or more windings; and determining that a fault has occurred if the judgement is positive; wherein in the judging process each of the selected harmonics of the supply frequency is a harmonic frequency of the supply frequency other than the supply frequency itself.
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Citations
17 Claims
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1. A method of detecting a fault in an induction machine having one or more windings, the method comprising:
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detecting a phase component of a driving current flowing in a stator of one or more windings of the induction machine at a supply frequency; generating a predetermined fault frequency based on a slip of the induction machine, the slip of the induction machine being based on a rotational speed of a rotor of the induction engine relative to a rotational speed of the stator in the induction machine and the supply frequency of the current flowing in the induction machine; determining whether a respective sideband of one or more selected harmonics of the supply frequency exists at the generated predetermined fault frequency in a signal in the one or more windings, each of the one or more selected harmonics of the supply frequency being a harmonic frequency higher than the supply frequency; determining that a fault has occurred in the one or more windings of the induction machine in response to determining that the existence of the respective sideband of one or more selected harmonics of the supply frequency is at the generated predetermined fault frequency; determining whether a power distribution of at least one of the one or more selected harmonics to the respective sidebands is below a predetermined threshold; and responsive to the power distribution being below the predetermined threshold, determining and identifying a fault type in the induction machine based on identifying fault frequency components of the selected harmonics of the supply frequency, other than the supply frequency itself; and in response to identifying the fault type in the induction machine, instructing a repair the induction machine based on the identified fault type determined using the fault frequency components of the selected harmonics of the supply frequency, such that the repair eliminates the determined fault, whereby the fault in the induction machine is determined and identified at a lower frequency resolution, a lower slip, and a lower fault severity allowing for earlier and more reliable detection of the fault to prevent permanent failure/damage of the induction machine. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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Specification