Dry-Contact Relay Interface for Remote Switch Status Signaling
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Solution Overview
Problem
Existing electrical switching devices, such as contactors, often lack the capability to remotely transmit their status information, relying solely on local indicators like light signals, which limits remote monitoring and maintenance.
Innovation Solution
A low-power communication device is designed to associate with electrical switching devices, utilizing a capacitor to recharge and power a bistable relay, creating a dry electrical contact that can signal the device's state, allowing remote monitoring without the need for a battery or significant power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If a communication device is added to an electrical switching device to enable remote status monitoring, then remote monitoring capability is improved, but device complexity increases
Solution Approach 1:
The communication device is nested within the housing of the electrical switching device, with the connector directly interfacing with the control circuit of the switching device. This integration allows the communication device to leverage existing structural elements and electrical connections of the switching device, thereby enabling remote monitoring capability while minimizing the increase in overall device complexity
Solution Approach 2:
The device incorporates a bistable relay that can maintain two stable states (energized and de-energized), allowing a single component to represent multiple status conditions. The dry electrical contact provides a universal interface that can be read by various external monitoring systems, making the communication function adaptable to different monitoring applications without requiring additional specialized components
2Loss of information
If a communication device with active electronics is added to transmit status information, then remote monitoring capability is improved, but power consumption increases
Solution Approach 1:
The device uses a capacitor that charges periodically when the control circuit is in a specific state (e.g., when a control terminal is energized). The pulse generator triggers the bistable relay only when the capacitor reaches a predefined charge level, converting continuous potential power consumption into periodic, event-driven action. This allows status information to be transmitted at relevant moments without requiring continuous power consumption
Solution Approach 2:
The communication device is powered directly from the control circuit's supply voltage without requiring an external power source or battery. The capacitor stores energy from the control circuit's voltage, and the pulse generator uses this stored energy to energize the relay coil when needed. The device essentially services itself using the existing electrical infrastructure of the switching device, eliminating the need for separate power supply components
3Ease of operation
If a battery-powered communication device is used for remote monitoring, then operational independence is improved, but device complexity and cost increase
Solution Approach 1:
The device is designed to operate autonomously by drawing power directly from the control circuit's supply voltage. The capacitor automatically charges when the control circuit provides voltage, and the pulse generator automatically triggers the relay when the charge threshold is reached. This self-service operation eliminates the need for batteries, power management circuits, or external power supplies, thereby maintaining operational independence while reducing device complexity and cost
Solution Approach 2:
The power supply function is merged with the control circuit's existing voltage source. Instead of implementing a separate power supply system, the device combines its power acquisition, energy storage (capacitor), and signal transmission functions into a single integrated unit that operates from the control circuit's voltage. This merging eliminates redundant components and simplifies the overall system architecture
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables remote monitoring of switching device status through a dry electrical contact, maintaining low energy consumption and simplicity, while avoiding the need for a self-contained power source, thus enhancing maintenance efficiency without impacting the switching device's energy performance.
Implementation Method 1
a capacitor (10) configured to be recharged from the supply voltage received from the input connector (4) when the status signal takes a predefined value
Implementation Method 2
a bistable relay (12) comprising a normally open electrical contact connected to output terminals (20) of the communication device to form a dry electrical contact
Data Source
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AI summary
A communication device (2) includes an actuator controlled by a control circuit, the communication device (2) includes: - a connector (4) suitable for connection to the control circuit, to receive a status signal (Ena) sent by the control circuit and to receive an electrical supply voltage (15V) supplied by the switching device; - a capacitor (10) configured to be recharged from the supply voltage received from the input connector when the status signal takes a predefined value; - a bistable relay (12) having a normally open (NO) electrical contact (18) connected to output terminals (20) to form a dry electrical contact; and - a pulse generator (8) powered by the capacitor and configured to excite the bistable relay when the capacitor reaches a predefined charge level.