Capacitor Leakage Detection Fixture Using Impedance Heating
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Solution Overview
Problem
Conventional methods for detecting capacitors with leakage current often result in unnecessary damage to sound capacitors during testing, as they require removal from the load board and rely on guesswork, leading to inefficient maintenance and incorrect identification of defective capacitors.
Innovation Solution
A detecting fixture comprising a reference voltage generator, impedance converter, comparator, and display unit, which allows for in-situ testing of capacitors in parallel connection without removal, using a voltage comparison and LED indication to identify capacitors with leakage current, leveraging the impedance change upon heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a capacitor is pulled out from the load board for detection, then the capacitor can be tested with a multi-meter, but the originally sound capacitor may be damaged during pulling out
Solution Approach 1:
The patent extracts the detection function from the physical removal process. Instead of pulling out the capacitor to test it, the testing device is brought to the capacitor on the load board. The probe contacts the capacitor terminals directly on the board, extracting only the necessary electrical connection for testing while leaving the capacitor in its original position, thus avoiding mechanical damage from removal.
2Ease of operation
If maintenance personnel locate defective capacitors by experience or guessing, then the detection process can be simplified, but the real defective capacitor cannot be located correctly and maintenance time increases
Solution Approach 1:
The patent uses visual indication through color changes to identify defective capacitors. The testing device displays different colors (e.g., green for normal, red for defective) based on the leakage current measurement, allowing maintenance personnel to quickly and accurately identify defective capacitors without time-consuming manual testing or guessing, thus reducing maintenance time while maintaining operational simplicity.
Solution Approach 2:
The testing device provides immediate feedback through visual display and audible signals when a defective capacitor is detected. The device automatically judges whether the measured leakage current exceeds the threshold and provides corresponding feedback, eliminating the need for personnel to manually analyze measurements and significantly reducing the time required to locate defective capacitors.
3Measurement precision
If multiple capacitors are tested individually by pulling them out, then each capacitor can be thoroughly tested, but the entire maintenance process becomes time-consuming and complex
Solution Approach 1:
The testing device is designed with multi-functionality to test multiple types of capacitors (different voltages, capacitances, and configurations) using the same device and procedure. It can handle various capacitor packages and circuit board types, allowing thorough testing of all capacitors in a system without requiring different testing methods or procedures for each type, thus maintaining test thoroughness while improving overall maintenance efficiency.
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
This method effectively reduces the risk of damaging sound capacitors and accurately locates defective capacitors with leakage current, shortening maintenance time and improving the efficiency of circuit testing.
Implementation Method 1
The comparator is respectively coupled with the output of the reference voltage generator and the output of the impedance converter for comparing the first voltage with the second voltage
Implementation Method 2
As a capacitor in the capacitor group in parallel connection is heated, the second voltage would be changed and the comparator outputs a voltage difference in response to the changed second voltage
Implementation Method 3
the display unit further has a light-emitting diode (LED), wherein the anode thereof is grounded, while the cathode thereof is coupled with the negative voltage output
Data Source
AI summary
A detecting fixture for detecting a capacitor with leakage current among a capacitor group in parallel connection includes a reference voltage generator, an impedance converter, a comparator and a display unit. Wherein, the reference voltage generator is used for outputting a first voltage, the impedance converter is used for converting the impedance of the capacitor group in parallel connection into a second voltage and the comparator is respectively coupled with the outputs of the reference voltage generator and the impedance converter for comparing the first voltage with the second voltage. The display unit is coupled with the output of the comparator, wherein the second voltage is altered by heating a capacitor among the capacitor group in parallel connection and the comparator outputs a voltage difference in response to the altered second voltage, so that the display unit is able to indicate whether or not the corresponding capacitor has leakage current.