Bi-Blade Contactor with Ferrous Plates for High Current
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Solution Overview
Problem
Existing high-current electrical contactors, such as those used in smart meters, face challenges in switching currents above 80 amps without welding at short-circuit faults, requiring expensive silver-alloy contacts and significant space, while also needing to be cost-effective and compact.
Innovation Solution
A smaller, cost-reduced bi-blade switch arrangement using shorter, narrower spring-copper blades with ferrous plates and an electromagnetic actuator, which reduces the number of contacts needed and enhances magnetic attraction forces to manage higher currents, incorporating a lead/lag contact arrangement for optimized silver-alloy usage and tungsten-oxide additive inclusions to prevent tack welding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silver-alloy contacts are used to prevent welding at high currents, then reliability is improved, but cost increases
Solution Approach 1:
The contactor is divided into multiple poles (first pole and second pole), with each pole handling a portion of the total current. This segmentation allows the use of less expensive contacts per pole while maintaining overall reliability for high-current applications.
Solution Approach 2:
The patent changes the operational parameters by introducing sequential closing timing between poles. The first pole closes before the second pole, allowing current to be gradually transferred and managed, which reduces peak stress on individual contacts and enables the use of cost-effective contact materials.
2Volume of moving object
If a compact contactor design is implemented, then volume is reduced, but manufacturing complexity increases
Solution Approach 1:
The actuating arrangements for both poles are merged into a single integrated mechanism. The movable arms and actuating components are designed to operate both poles from a common structure, reducing overall device volume while managing the complexity through unified design rather than separate independent systems.
Solution Approach 2:
The patent implements periodic/sequential action where the first pole closes before the second pole. This time-sequenced operation allows the compact design to manage high-current switching safely by stagging the closing action, reducing simultaneous mechanical and electrical stress in the compact structure.
3Reliability
If sequential contact closing is implemented, then reliability under short-circuit conditions is improved, but device complexity increases
Solution Approach 1:
The first pole closes preliminary before the second pole. This preliminary action establishes a safe initial circuit state, allowing subsequent current transfer to the second pole in a controlled manner. This sequential timing protects against simultaneous arcing and reduces short-circuit stress, improving reliability without requiring complex external control systems.
Solution Approach 2:
The actuating arrangement is designed to automatically execute the sequential closing sequence through its inherent mechanical design. The movable arms and actuating components are configured so that the first pole naturally closes before the second pole during normal operation, eliminating the need for complex external control circuits or additional control components.
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 enables a more compact, cost-effective high-current contactor that maintains reliability and endurance life, reducing silver-alloy costs and allowing for a smaller form factor, while ensuring safe operation under short-circuit conditions without contact welding or explosive risks.
Implementation Method 1
an electromagnetic actuator, which reduces the number of contacts needed and enhances magnetic attraction forces to manage higher currents
Implementation Method 2
shorter, narrower spring-copper blades with ferrous plates and an electromagnetic actuator, which reduces the number of contacts needed and enhances magnetic attraction forces to manage higher currents
Implementation Method 3
tungsten-oxide additive inclusions to prevent tack welding
Data Source
AI summary
A switching electrical power contactor having a bi-blade type switch, has ferrous plates attached to the blades to increase the current carrying capacity and reduce the resistance of the switch. The contacts of the switches are arranged in pairs with at least one pair of contacts being arranged to close before another pair of contacts.