Thermal Reed Switch Overload Tripping for Circuit Breakers
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Solution Overview
Problem
The calibration process for bimetallic devices in circuit breakers is inefficient, costly, and results in significant nonconforming units due to varying displacement, requiring precise adjustment and lengthy testing, which is time-consuming and costly in mass production.
Innovation Solution
Implementing a thermal overload current detection mechanism using a Thermal Reed Switch with Thermorite® soft magnetic material that provides precise temperature-based tripping, eliminating the need for bimetallic device calibration and reducing production inefficiencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a microprocessor and ADC are used to detect overload current, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex electronic measurement systems (microprocessor and ADC) with a simple magnetic field-based detection mechanism. The magnetic field generated by current flowing through the conductor directly actuates the magnetic element, eliminating the need for electronic sensors and processors while maintaining detection functionality.
Solution Approach 2:
The magnetic field generated by the current itself serves as the detection signal. The current's own magnetic field directly actuates the magnetic element, creating a self-contained detection system that requires no external power source or additional sensing components.
2Device complexity
If conventional detection methods are used, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent substitutes electronic measurement systems with a direct magnetic field actuation mechanism. The magnetic element responds directly to the magnetic field generated by the current, providing a simple yet precise detection method that avoids the complexity of electronic sensors while maintaining high measurement accuracy.
Solution Approach 2:
The magnetic field acts as an intermediary between the current and the detection mechanism. Instead of directly measuring electrical parameters, the system measures the magnetic field generated by the current, which then actuates the magnetic element to indicate overload conditions.
3Measurement precision
If high measurement precision is achieved through electronic components, then overload detection accuracy is improved, but loss of energy increases
Solution Approach 1:
The system uses the current's own magnetic field as the detection signal, requiring no external power source. The magnetic element is actuated directly by the magnetic field generated by the current flowing through the conductor, eliminating energy consumption associated with electronic sensors and processors.
Solution Approach 2:
The patent replaces energy-consuming electronic measurement systems with a passive magnetic field-based detection mechanism. The magnetic element responds to the magnetic field without requiring active electronic components, thereby eliminating continuous power consumption while maintaining detection accuracy.
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 achieves precise and repeatable temperature-based tripping, reducing calibration time and waste, and improving production efficiency and yield, while adding minimal cost through the use of a Thermal Reed Switch.
Implementation Method 1
a magnetic element which, in use, detects a magnetic field generated by current flowing through the conductor
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A circuit interrupting device with overload current detection is provided. It comprises a hot conductor, a main contactor and a first electromagnetic device configured to remove power from an electrical circuit when overload current exceeds a predetermined % of a rated load current. It further comprises a section of conductor that generates heat and a thermal overload current detection mechanism including a temperature sensing switch having contacts. The temperature sensing switch closes the contacts when a temperature reaches a predefined temperature threshold corresponding to an overload current, in which case the temperature sensing switch electrically couples power to a second electromagnet which is disposed across the hot conductor and a connection to a neutral conductor. The energized second electromagnet generates a magnetic force capable of moving an armature that unlatches the latch releasing the spring to open the main contactor removing power from the electrical circuit.