Switch Contact Charge Dissipation via Parallel Resistor
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Solution Overview
Problem
Electric contacts often experience failures due to foreign matter accumulation, especially when in an open-circuit state for extended periods or in high-temperature environments, as they can become charged and attract insulating foreign particles.
Innovation Solution
An electronic device design that includes a power supply, a first switch, a second switch, and an electric element connected in parallel to the electric contact, preventing the contact from being charged when the switches interrupt power, thereby reducing foreign matter attraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electric contact is disconnected from the power supply and placed in an open-circuit state, then the circuit can be interrupted and controlled, but the electric contact becomes charged and attracts foreign matter causing contact failures
Solution Approach 1:
A leakage current path (through insulation resistance or a parallel resistor) is introduced as an intermediary to continuously discharge the electric contact, preventing charge accumulation and foreign matter attraction while maintaining the ability to interrupt the main power circuit
2Ease of operation
If the electric contact remains connected to the power supply, then foreign matter attraction is reduced, but the ability to interrupt power to the load is compromised
Solution Approach 1:
The circuit is segmented into a main power circuit (controllable by the switch) and a leakage current path (always active through insulation resistance or parallel resistor), allowing the main circuit to be interrupted while the leakage path continues to prevent charge accumulation
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
The solution effectively minimizes contact failures caused by foreign matter on electric contacts by maintaining the contact in a non-voltage state, even when the circuit is disconnected from the power supply, thus preventing foreign matter from being attracted.
Implementation Method 1
the electric contact is charged due to electrostatic conduction from outside and thus attracts foreign matter
Implementation Method 2
an electric element that is connected between the first and second power lines in parallel to the electric contact, such that the electric contact of the second switch is not charged when the first and second switches interrupt power
Data Source
AI summary
An electronic device (10) includes: a power supply (11); a first switch (12) that is connected at least to one pole of the power supply (11) and interrupts power supplied from the power supply (11) to a load (13); a second switch (14) that is positioned on a load (13) side with reference to the first switch (12) and interrupts power supplied from the power supply (11) to the load (13); a first power line (L11) that is connected to one end portion of an electric contact of the second switch (14), the one end portion being located on a first-switch (12) side; a second power line (L12) that is connected to another end portion of the electric contact of the second switch (14); a third power line (L13) that is connected to another pole of the power supply (11); and an electric element (resistor 15) that is connected between the first and second power lines (L11, L12) in parallel to the electric contact or connected between the first and third power lines (L11, L13), such that the electric contact of the second switch (14) is not charged when the first and second switches (12, 14) interrupt power.