Appliance Switching Circuit for Safe Load Sensing Before Door Lock
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Solution Overview
Problem
Conventional circuit arrangements for household appliances with hazardous components, such as washing machines, require users to lock the door to operate the device, disrupting communication and load sensing until the door is locked, making load optimization cumbersome and requiring multiple door openings and closings.
Innovation Solution
A circuit arrangement with a power supply connection, a hazardous component controller, a switching means, and a safety device that disconnects the controller from the power supply in hazardous states, while maintaining a low-energy connection via a consumer to allow auxiliary functionalities like load sensing and communication, eliminating the need for current-limiting resistors and simplifying the controller structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the safety device disconnects the controller from the power supply in hazardous states, then the hazardous component cannot be operated safely, but the controller loses power for auxiliary functions like load sensing and communication
Solution Approach 1:
The power supply connection is segmented into two separate connections: a first power supply connection that can be disconnected by the safety device for hazardous component power, and a second power supply connection that remains active for controller auxiliary functions. This segmentation allows independent control of power supply paths, enabling safety disconnection while maintaining controller functionality.
2Reliability
If the controller is completely disconnected from power supply in hazardous states, then safety is ensured, but communication between controller and main controller is interrupted
Solution Approach 1:
The power supply is segmented into hazardous component power path and controller auxiliary power path. The first connection supplies power to the hazardous component through the safety device, while the second connection independently supplies power to the controller for communication and sensing functions, preventing information loss during safety disconnection.
3Reliability
If the door must be locked before load sensing, then safety is maintained, but the user experience becomes cumbersome requiring multiple door operations
Solution Approach 1:
The controller is enabled to perform load sensing and communication functions before the door is locked by maintaining power supply through the second connection. This preliminary action allows the user to check load status and optimize loading while the door is still open, eliminating the need for multiple door lock-unlock cycles while maintaining safety protocols.
Data Source
AI summary
The circuit arrangement has a power supply terminal (36) and a load which is connected to the power supply terminal by a wiring cable (38). A controller (16) is provided for a hazardous component, which is connected to the power supply terminal by the wiring cable. A switching unit (18) is provided for switching on and off the controller. The load is connected between the power supply terminal and a security device (14). A connecting line (19) connects the controller with the power supply terminal over the load. An independent claim is included for a method for operating a household appliance.