Multi-Protector Fuse Circuit for Short Circuit Protection
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Solution Overview
Problem
Conventional fuses used for short circuit protection are disposable and require manual replacement after melting, leading to increased time and cost, and they do not meet the No-Arc, No-Fire, No-Smoke, and No-Damage Electric Short Circuit Test Standard.
Innovation Solution
An improved electric circuit structure employing a multi-protector fuse as the circuit breaking element, which includes a thermistor, a filtering and rectifying module, and a capacitor, allowing for repeated use without physical damage and compliance with the No-Arc, No-Fire, No-Smoke, and No-Damage Electric Short Circuit Test Standard.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional fuse is used for short circuit protection, then the circuit can be protected from damage, but the fuse itself becomes damaged and requires manual replacement
Solution Approach 1:
The circuit breaker is designed to automatically reset itself after tripping during a short circuit event. The thermal element cools down and the magnetic field dissipates, causing the breaker to automatically return to its closed state without requiring manual intervention, thus eliminating replacement time and maintaining continuous protection
Solution Approach 2:
Instead of discarding the fuse after one use, the circuit breaker recovers its protective function by automatically resetting. The thermal and magnetic elements recover their original states after the fault condition is removed, allowing the device to be reused indefinitely for short circuit protection
2Reliability
If a conventional fuse is used for short circuit protection, then the circuit can be protected from damage, but manual replacement increases operational cost
Solution Approach 1:
The automatic self-resetting capability eliminates the need for manual replacement operations, allowing the system to maintain continuous protective function without interrupting operational workflows, thus improving productivity and reducing operational costs
Solution Approach 2:
The circuit breaker maintains continuous protective action by automatically resetting after each trip event, ensuring uninterrupted protection coverage and eliminating downtime associated with manual fuse replacement, thereby improving overall system productivity
3Reliability
If a conventional fuse is used for short circuit protection, then the circuit can be protected, but it does not meet the No-Arc, No-Fire, No-Smoke, and No-Damage safety standard
Solution Approach 1:
The patent replaces the simple thermal-melting mechanism of conventional fuses with a dual thermal-magnetic tripping mechanism. The magnetic component provides instantaneous response to high currents without thermal accumulation, preventing arc formation and associated harmful effects like fire and smoke, while meeting the No-Damage requirement through controlled opening
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 multi-protector fuse effectively protects devices from short circuits without physical damage, reducing replacement costs and ensuring compliance with safety standards, with a fusing time less than 120 seconds and an allowable temperature range of 190°C to 230°C, and passing the DC 4kV Hi-pot test.
Implementation Method 1
a thermistor, including a first end and a second end, wherein the first end of the thermistor is electrically connected to a ground
Implementation Method 2
when a short circuit condition occurs in the circuit electrical path and the current flowing through it is too large, the metal wire or metal sheet therein will be melted due to the high temperature, resulting in an open circuit and interrupting the current
Implementation Method 3
a filtering and rectifying module, being electrically connected between the second end of the circuit breaking element and the second end of the thermistor
Data Source
Figure 1
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Figure 3
AI summary
An improved electric circuit structure for short circuit protection (1) is applicable to examining a device under test (10), comprising a circuit breaking element (11), a thermistor (13), a filtering and rectifying module (15) and a capacitor (17). A first end (111) of the circuit breaking element (11) is connected to power source (21). A first end (131) of the thermistor (13) is connected to ground (31). The filtering and rectifying module (15) is connected between second end (112) of the circuit breaking element (11) and second end (132) of the thermistor (13). The capacitor (17) is connected to the filtering and rectifying module (15) and in parallel with the device under test (10). The circuit breaking element (11) is a multi-protector fuse, forms an open circuit when device under test (10) forms short circuit, and withstands voltage between its first and second end without physical damage.