Monitoring the bearing temperature of an electrical machine
First Claim
1. A method for monitoring a temperature of at least one bearing of an electric machine which has a plurality of machine components, comprising the steps of:
- defining a temperature model for the machine,simulating thermal conditions in the electric machine based on a multiple-mass model,continuously measuring an electric current in the electric machine and supplying the measured electric current as an input variable for the temperature model,continuously measuring a rotation speed of the electric machine as an input variable for the temperature model,deriving from the temperature model at least one calculated bearing power loss, which corresponds to a temperature of a bearing or a temperature of a bearing inner ring,emitting a first warning message if the calculated bearing power loss is greater than a predetermined comparison value, oremitting a second warning message if a calculated temperature difference between a bearing inner ring and an associated bearing outer ring exceeds a predetermined temperature difference, or both.
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Abstract
According to the method a temperature module is defined, simulating the thermal behavior in the electric motor (1), based on a multi-mass model. The rotational speed (n) and the current (i) for the electric motor (1) are continuously recorded as input parameters for the temperature model and at least one bearing power loss and/or bearing inner temperature (TIL1′), corresponding to a bearing (8,9), is continuously derived from the temperature model. A first warning signal (W1) is given when a computer-determined bearing power loss exceeds a given comparative value. Furthermore, a second warning signal (W2) is given when a computer-determined bearing inner ring temperature exceeds a given temperature difference (ΔT) from a corresponding computed bearing outer ring temperature (TAL1′). The thermal behavior of non-accessible components, in particular, the bearing (8, 9), can thus advantageously be determined by mere evaluation of the current (i) and the rotational speed (n). The fitting of temperature sensors (2, 3, 4, 12) in the electric motor (1) can also be avoided.
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Citations
19 Claims
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1. A method for monitoring a temperature of at least one bearing of an electric machine which has a plurality of machine components, comprising the steps of:
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defining a temperature model for the machine, simulating thermal conditions in the electric machine based on a multiple-mass model, continuously measuring an electric current in the electric machine and supplying the measured electric current as an input variable for the temperature model, continuously measuring a rotation speed of the electric machine as an input variable for the temperature model, deriving from the temperature model at least one calculated bearing power loss, which corresponds to a temperature of a bearing or a temperature of a bearing inner ring, emitting a first warning message if the calculated bearing power loss is greater than a predetermined comparison value, or emitting a second warning message if a calculated temperature difference between a bearing inner ring and an associated bearing outer ring exceeds a predetermined temperature difference, or both. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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Specification