Method for detecting electrical faults with a multimeter
How to use a multimeter to test and detect electrical faults, it is difficult to capture the electrical parameters when the fault occurs, which adds great difficulties to the detection.
There are many testing equipment that can make intermittent fault diagnosis simple.
These devices include complex signal analyzers and digital oscilloscopes, as well as simple and easy-to-use handheld multimeters. Digital multimeters also require measurement and recording capabilities for basic measurement functions (AC voltage, DC voltage, and resistance measurement), and can be combined with standard tables to detect intermittent fault parameters.
In the past, people used mechanical paper tape recorders to continuously record voltage or current. During work, it was necessary to connect voltage to the input or clamp the current sensor on the wire. The recorder would print the changes in voltage or current on the paper tape, and the maximum length recorded depends on the amount of paper on the paper.
1、 Intermittent faults recorded by a multimeter
Using the minimum/maximum/average value recording mode of a multimeter, select the corresponding function (AC voltage, DC voltage, resistance, AC current, DC current, and frequency) based on the measurement item, ensuring that the test circuit is connected before activating the minimum/maximum/average value function. Otherwise, the minimum value reading will always be the environmental value before the test line is connected.
This will affect the analysis of recorded data after the end of the recording time, activate the minimum/maximum/average value recording mode, and the multimeter display screen will indicate the maximum reading, and a beep will sound when a new maximum or minimum value is detected.
Advantages: When ensuring that the digital multimeter is not tampered with and does not pose any safety hazards to humans, the digital multimeter can be left in place for measurement and focused on other tasks. At any time during the recording cycle, you can view the saved readings or pause the recording mode without deleting the saved readings.
2、 The multimeter continuously records intermittent faults
Some multimeters not only have the function of recording minimum/maximum/average values, but also combine this function with another function called AutoHOLD and a larger memory to enhance Event Logging function.
The automatic maintenance function can sense when the measurement signal becomes unstable and when it stabilizes again. By using the automatic hold function to trigger the start and stop of the minimum/maximum value recording function, the digital multimeter is not limited to detecting faults that generate minimum or maximum values.
If the multimeter has an infrared RS232 interface, continuous recording power will be more powerful and can become a simple event collector, transmitting the data collected by the multimeter to a computer.
By using computers, detailed analysis can be conducted on each stable and unstable event.
Not only can you view the minimum and maximum values within each stable and unstable cycle, but you can also view the start and end times of each cycle. Additionally, record the average value for each cycle. At the same time, it can dynamically detect the change of voltage or current Run chart.
