Connector-Integrated Varistor Plate for Fast EMP Surge Protection
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Solution Overview
Problem
Existing varistors are ineffective against fast, high-energy pulses due to their reaction times and the use of flying leads, which introduce inductance and RF coupling, limiting their ability to protect against electromagnetic pulses (EMPs) and electromagnetic interference (EMI) in military and commercial applications.
Innovation Solution
A varistor plate integrated into an electrical connector with pins that act as conductive layers, eliminating the need for flying leads and reducing inductance, along with a thermally-activated override to prevent degradation, allowing for faster reaction times and improved protection against high-frequency noise and transient pulses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If traditional flying leads are used to connect varistor terminals to the circuit, then the varistor can be physically connected to the circuit, but the reaction time is limited due to inductance introduced by the flying leads
Solution Approach 1:
The patent merges the varistor element with the electrical connector housing, integrating the protection device directly into the connector structure. The varistor terminals are connected directly to the connector pins without separate flying leads, combining multiple functions into a single integrated component that reduces inductance and improves reaction time.
Solution Approach 2:
The patent extracts and eliminates the flying leads from the connection path between the varistor terminals and the circuit. By removing these intermediate conductive elements, the design achieves direct connection between the varistor and the circuit through the connector pins, thereby reducing inductance and improving speed.
2Object-affected harmful factors
If flying leads are used to connect the varistor, then the varistor can be connected to the circuit, but RF coupling occurs between cables at high frequencies above 10 MHz, allowing transient pulses to bypass the varistor
Solution Approach 1:
The patent removes the flying leads that act as antennas and cause RF coupling. By eliminating these intermediate conductive elements and establishing direct connections through the connector pins, the design prevents high-frequency transient pulses from bypassing the varistor through cable coupling, thereby improving protection effectiveness.
3Use of energy by moving object
If large varistors are used to handle peak currents and energies, then the energy handling capability is improved, but the reaction time becomes slower
Solution Approach 1:
The patent combines the varistor element with the connector housing to create an integrated protection device. This integration reduces the overall inductance of the connection path, allowing larger varistors to respond faster by minimizing the inductive time constant (τ = L/R) in the circuit.
Solution Approach 2:
The patent changes the inductance parameter of the connection path by eliminating flying leads and using direct connections through connector pins. This parameter change reduces the inductive time constant, enabling the varistor to respond faster even when handling large peak currents and energies.
4Reliability
If the varistor is placed upstream of the power input to protect against EMP and IEMI, then effective protection is provided, but the flying leads act as inductors wired in-series, slowing the reaction time
Solution Approach 1:
The patent integrates the varistor protection device directly into the electrical connector housing, placing it upstream of the power input as required for EMP and IEMI protection. The integration eliminates series inductors by using direct connections through the connector pins, maintaining reliability while improving reaction time.
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 enhances the reaction time of varistors, reduces inductance, and provides effective filtering and protection against EMPs and EMI, while also addressing the issue of varistor degradation through thermal disconnection and monitoring.
Implementation Method 1
it is substantially dielectric (an electrical insulator) at low voltages, but which undergoes dielectric breakdown above a specified threshold voltage, thus rendering it electrically conductive
Implementation Method 2
the bimetallic disc is configured to undergo a one-way shape change upon heating
Data Source
AI summary
An electrical connector provided with a varistor, and to a protection device for incorporation into an electrical connector and having a varistor comprising at least two pins including a first pin which is a live (502) or neutral (504) pin and a second pin which is an earth pin (506), the first and second pins (502, 504, 506) extending through respective apertures (512) in a varistor plate (514) which has first and second faces, wherein a first conductive layer on the first face of the varistor plate (514) connects electrically to the first pin (502, 504) and a second conductive region on the second face of the varistor plate connects electrically to the second pin (506), so that in response to an excessive voltage across the first (502, 504) and second (506) pins the varistor plate will conduct electricity between the first (502, 504) and second (506) pins. The arrangement can easily be adopted in connectors conforming to existing standards, such as existing mains electrical plugs (500).