| 摘要 |
A loose electrical connection in an electrical apparatus such as an electricity meter is detected by measuring the rate of change of temperature in a housing that contains one or more electrical connections. The temperature sensor 17 measures the ambient air temperature inside the housing and a processor 14 computes the rate of change of temperature, or the acceleration of temperature i.e. the second derivative of temperature with respect to time. The rate of change or acceleration in temperature may be compared to a threshold stored in memory 15. A switch 18 may be activated to cut off the electricity supply if the temperature rate of increase or acceleration is too high, or an alarm signal may be generated. The current in the meter may be measured by current sensor 13 to compensate for changes in load. A thermal model of the apparatus may be used to determine the threshold.
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