Sequential Switch Interlock to Prevent Mechanical Contact Arcing
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Solution Overview
Problem
Arc discharge occurs during the opening and closing of mechanical switches in circuits with power electronic switches, reducing the service life and reliability of mechanical switches, and there is a lack of sequential interlock between mechanical and power electronic switches, leading to safety hazards.
Innovation Solution
A sequential action device that controls the power electronic switch and mechanical switch in series, ensuring the mechanical switch is closed before the power electronic switch is turned on and opened after the power electronic switch is turned off, using a triggering device, mechanical operating mechanism, detection circuit, and software control circuits to manage the sequence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanical switch and power electronic switch are connected in series without sequential interlock, then the circuit can operate with both switches, but arc discharge occurs during mechanical switch operation which reduces service life and reliability
Solution Approach 1:
The control unit is configured to control the power electronic switch to turn off before the mechanical switch opens, and to turn on after the mechanical switch closes. This preliminary action prevents arc discharge by ensuring the power electronic switch is already off when the mechanical switch opens, eliminating the harmful arc discharge effect while maintaining reliable operation of both switches in series
2Ease of operation
If the mechanical switch opens and closes independently without coordination with the power electronic switch, then the mechanical switch can operate freely, but arc discharge occurs compromising contact life and contact reliability
Solution Approach 1:
The control unit establishes a coordinated control relationship between the mechanical switch and power electronic switch through feedback mechanisms. The control unit monitors the mechanical switch state and adjusts the power electronic switch timing accordingly, ensuring the power electronic switch turns off before mechanical switch opening and turns on after mechanical switch closing, thereby preventing arc discharge while maintaining operational coordination
Data Source
AI summary
The present disclosure relates to an electromechanical sequential action device that is capable of sequentially interlocking a mechanical switch and a power electronic switch, where through an action sequence control, the electromechanical mechanism turns on the power electronic switch only after the mechanical switch is closed, and through an advanced travel control, turns off the power electronic switch before opening the mechanical switch, avoiding the problem of arc discharge during closing and opening of the mechanical switch, and improving the service life and connection reliability of the mechanical switch.