Power Off Device Detecting Micro Arcs and High Current Arcs
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Solution Overview
Problem
Conventional power off devices cannot detect and respond to continuous voltage type micro arcs and high current type arcs that may cause fires, nor do they effectively handle overheat situations due to overload or momentary voltage drops, limiting their ability to prevent electrical accidents.
Innovation Solution
A power off device incorporating a micro arc detector, high current arc detector, delay unit, power off unit, and overload detector that utilize high frequency pulse currents, magnetic field variations, and delay capacitors to distinguish between hazardous and non-hazardous arcs, allowing for precise power cutoff.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If arc detection function is added to power off device, then fire prevention capability is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple detection functions (micro arc detection, high current arc detection, and overload detection) into a single integrated power off device. The micro arc detector, high current arc detector, and overload detector share common circuitry and control logic, allowing the device to perform multiple safety functions without proportionally increasing complexity.
Solution Approach 2:
The power off device is designed with multi-functionality to detect and respond to various abnormal conditions including micro arcs, high current arcs, and overloads. A single device handles multiple types of electrical anomalies that would otherwise require separate protection mechanisms, improving reliability while managing complexity through unified design.
2Reliability
If power is cut off whenever arc is detected, then fire prevention is improved, but normal use of electric appliances becomes difficult
Solution Approach 1:
The patent applies different detection thresholds and response characteristics to different types of arcs. Micro arc detection uses one set of parameters while high current arc detection uses another, allowing the system to distinguish between harmful arcs requiring power cutoff and benign arcs during normal operation. This localized differentiation enables selective response based on arc characteristics.
Solution Approach 2:
The system changes detection parameters based on the type of arc detected. For micro arcs, the detection threshold and time constant are optimized to distinguish continuous arcs from momentary switching arcs. For high current arcs, different current thresholds are applied. These parameter adjustments allow the device to maintain sensitivity to dangerous conditions while avoiding false tripping during normal appliance operation.
3Measurement precision
If micro arc detection sensitivity is increased, then continuous arc detection is improved, but false detection during normal switching increases
Solution Approach 1:
The patent employs periodic sampling and time-based detection methods to distinguish continuous arcs from momentary switching arcs. The micro arc detector monitors the power line over extended periods and identifies patterns of continuous arc presence versus transient arcs during normal switching operations. This temporal analysis enables accurate detection while filtering out false positives from routine appliance switching.
Solution Approach 2:
The system performs preliminary analysis of detected arcs to determine their characteristics before triggering power cutoff. The micro arc detector first identifies potential arc events, then analyzes their duration, intensity pattern, and temporal characteristics to distinguish hazardous continuous arcs from benign switching arcs. This preliminary discrimination prevents false detection during normal appliance operation.
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 device effectively prevents fires and electrical accidents by accurately detecting and responding to micro arcs, high current arcs, and overloads, ensuring safe operation without unnecessary power disruptions during normal use.
Implementation Method 1
a voltage induced in a high frequency choke coil by a high frequency pulse current caused by micro arc
Implementation Method 2
a magnetic field generated at a coil installed at the power line due to high current arc
Data Source
AI summary
Disclosed is a power off device which includes a micro arc detector for turning on a first switching element, based on a voltage induced in a high frequency choke coil by a high frequency pulse current caused by micro arc at a power line, a high current arc detector for outputting a high current arc detection current during turning-on of a second switching element made based on variation of a magnetic field generated at a coil, a delay unit for accumulatively charging the micro arc detection current or the high current arc detection current in a delay capacitor at a predetermined time constant, a power off unit for electrically disconnecting a load from the power line when an operating voltage is applied, and a first switch for connecting the operating voltage to the power off unit in response to the arc detection signal.