Elevator Contactor Fault Detection via Three-Phase Voltage Sensing
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Solution Overview
Problem
The industry lacks a simple, reliable, and low-cost method for detecting the functionality of a contactor in elevator systems, which is crucial for safety protection.
Innovation Solution
A device comprising a control unit, a switch, a contactor, and a function detection unit that includes a voltage or current detection system to assess the contactor's functionality by measuring voltage or current signals, using integrators and analog-to-digital converters to determine deviations from set ranges, indicating abnormal conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If contactor function detection is implemented using conventional methods, then reliability is improved, but device complexity increases and cost increases
Solution Approach 1:
The contactor performs self-detection by utilizing its own coil winding as the detection object. The control unit injects a detection signal through the contactor coil and measures the resulting voltage or current to determine contactor health status, eliminating the need for separate detection hardware.
Solution Approach 2:
The contactor coil serves dual purposes: it functions as both the actuating component for contactor operation and as the detection object for health monitoring. The same coil winding is used for both driving the contactor and detecting its functional status.
2Device complexity
If simple detection methods are used, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The control unit continuously monitors the voltage or current in the contactor coil and compares it against expected values to detect abnormalities. This feedback mechanism enables precise detection of contactor health status using simple measurement circuits.
Solution Approach 2:
The detection method monitors changes in electrical parameters (voltage or current) of the contactor coil to infer contactor health status. By tracking parameter deviations, the system achieves precise detection without complex measurement equipment.
3Reliability
If comprehensive detection is performed, then reliability is improved, but loss of time increases
Solution Approach 1:
The control unit performs detection at periodic intervals or at specific moments (e.g., when contactor state changes), rather than continuously. This periodic detection approach maintains reliability while minimizing time loss and system resource consumption.
Data Source
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AI summary
The present application relates to elevator safety technology, and in particular to a device for detecting a function of a contactor and elevator functionality device comprising the device. According to an aspect of the present application, there is provided a device for detecting a function of a contactor, wherein the contactor is configured to short three-phase phase lines of an elevator motor together by closing contacts, the device comprising: a voltage signal source coupled with the contactor; a voltage detection unit coupled with the three-phase phase lines of the elevator motor; a switching unit arranged between the contactor and the voltage signal source and between the voltage detection unit and the three-phase phase lines, wherein, in a detection mode, the switching unit is configured to conduct the voltage signal source to the contactor to provide a voltage detection signal to the three-phase phase lines via the contactor and to conduct the voltage detection unit to the three-phase phase lines, the voltage detection unit being configured to measure voltage of the three-phase phase lines and to output measurement to a control unit.