Self-Identifying Zero Wire Circuit for Heat Generating Plate
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Solution Overview
Problem
Incorrect wiring between live and zero wires leads to excessive current leakage, electrified machine housings, and abnormal leakage protector operations, posing safety risks in high-voltage electrical devices.
Innovation Solution
An electronic circuit with a voltage sampling terminal connected via a resistor to a protective ground wire, a voltage comparing circuit, and a selecting circuit that identifies correct or incorrect wiring by comparing voltages and adjusts connections to ensure safe operation, integrated with a heat generating plate having zero wire connecting layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a leakage protector is added to prevent safety accidents, then safety protection is improved, but device complexity increases
Solution Approach 1:
The patent combines the zero wire identification function with the existing leakage protector circuit by integrating a voltage sampling terminal and comparing circuit into the leakage protector's control circuit. This merging approach allows the leakage protector to simultaneously perform its original safety function and the new zero wire identification function, avoiding the need for a separate identification device and thus not increasing overall device complexity.
Solution Approach 2:
The leakage protector is designed to serve multiple functions: it continues to provide leakage protection while also performing zero wire identification. The control circuit is modified to universally handle both leakage detection and zero wire identification tasks, making the device multi-functional and eliminating the need for additional dedicated components.
2Measurement precision
If voltage sampling and comparing circuits are added for zero wire identification, then identification accuracy is improved, but device complexity increases
Solution Approach 1:
The voltage sampling terminal and comparing circuit are integrated into the existing leakage protector control circuit rather than being added as separate standalone components. The sampling terminal utilizes the existing control circuit nodes, and the comparing circuit shares operational amplifiers and other components with the leakage detection circuit, thereby achieving zero wire identification functionality without proportionally increasing device complexity.
3Reliability
If the selecting circuit switches connections based on identification results, then safety under incorrect wiring is improved, but device complexity increases
Solution Approach 1:
The selecting circuit employs a dynamic switching mechanism using a triode and relay that automatically adjusts the connection configuration based on the zero wire identification result. The switch transitions between two states: normal connection under correct wiring and switched connection under incorrect wiring. This dynamic adaptation ensures safety without requiring complex manual intervention or multiple static circuit configurations.
Solution Approach 2:
The system performs preliminary zero wire identification before the main operating circuit is fully activated. The voltage sampling and comparing circuits detect wiring correctness in advance, and the selecting circuit is pre-configured to switch connections if incorrect wiring is detected, preventing safety issues before they occur rather than responding after problems arise.
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
Prevents accidents by ensuring safe operation even with incorrect wiring, avoiding excessive leakage and abnormal protector operations, and maintaining safety by maintaining the zero wire connection in the event of incorrect wiring.
Implementation Method 1
a voltage comparing circuit configured to compare a voltage at the voltage sampling terminal with a divided voltage of the electronic circuit
Implementation Method 2
the voltage sampling terminal connected with a protective ground wire via a first resistor
Data Source
Figure 1~2
AI summary
Provided are an electronic circuit (Fig. 1) for self-identifying a zero wire (N, J2), and a heat generating plate (Fig. 2) having the same. In case of a correct wiring of the electronic circuit for self-identifying the zero wire, a device operates normally; while in case of an incorrect wiring where a zero wire is connected with a live wire (L, J1), and a live wire is connected with a zero wire, a zero wire layer (2, 3) of an external device is connected with the live wire, however, as the live wire is connected with the zero wire, the external device is still in a safe state, thereby avoiding a problem in prior art that accidents frequently occur due to the incorrect wiring which causes phenomena such as an excessive leakage, an electrified machine housing, and an abnormal operation of leakage protector. Moreover, since the heat generating plate is provided with zero wire layer on both sides of the heat generating layer (1), there is no leakage current at a machine housing when the machine operates, thereby it is possible to ensure safety performance of the machine. Fig. 1