Technical Information
Solid insulating material comparative tracking index measurement and detection
[ 12-11-2024 ]
The comparative tracking index (CTI) of solid insulating materials is an important indicator to measure the leakage resistance of materials under the combined action of electric field and humid or contaminated medium. The following is a method to measure the comparative tracking index of solid insulating materials:
1. Test standard
The test of comparative tracking index usually follows the relevant provisions of the International Electrotechnical Commission (IEC) or national standards (GB), such as IEC 60112 or GB/T 4207. These standards specify the requirements for test methods, test conditions, test equipment and data processing in detail.
2. Test equipment
The test equipment mainly includes a tracking tester, electrodes, electrolytes, timers, etc. The tracking tester is designed according to the simulation test items specified in the relevant standards. It can apply a specific electric field and drip electrolytes at regular intervals to observe and record the tracking time. The electrodes are usually platinum electrodes, and their shape, size and surface treatment must meet the standard requirements. The electrolyte is generally an ammonium chloride solution, and its concentration and dripping speed must also be controlled according to the standards.
3. Test steps
Sample preparation: Cut the solid insulating material into samples of specified size (such as 2mm×5mm×12mm) and perform necessary surface treatment, such as cleaning and drying.
Test condition setting: Under standard atmospheric pressure, the temperature of the test environment is controlled at 23℃±5℃, and the humidity must also meet the standard requirements. Apply a 50Hz sine wave voltage between the electrodes, and the voltage value must be selected according to the standard or the characteristics of the material to be tested.
Apply an electric field and drip electrolyte: Place the sample between the electrodes and apply an electric field. At the same time, drip the electrolyte according to the time interval and drip height specified by the standard.
Observation and recording: Observe and record the tracking of the sample surface, including tracking time, tracking length, etc. When the sample fails due to tracking (such as continuous burning, arc discharge, etc.), stop the test immediately.
Data processing: Calculate the comparative tracking index according to the test data and the method specified in the standard. Generally, the comparative tracking index refers to the ratio of the maximum voltage value (or voltage range) of 5 specimens subjected to 50 drops of liquid without tracking failure and continuous burning to the corresponding value of the reference material.
IV. Precautions
Sample preparation: The shape, size and surface treatment of the sample must meet the standard requirements to ensure the accuracy and comparability of the test results.
Test environment: The temperature, humidity and other conditions of the test environment must be strictly controlled to reduce the impact of external factors on the test results.
Equipment calibration and maintenance: The test equipment must be calibrated and maintained regularly to ensure its normal operation and the accuracy of the test results.
Safe operation: Safety operating procedures must be followed during the test to prevent safety accidents such as electric shock and fire.
V. Application and significance
The measurement of the comparative tracking index is of great significance for evaluating the leakage resistance of solid insulating materials. It can help manufacturers select suitable insulating materials and improve the safety and reliability of products. At the same time, the comparative tracking index is also one of the important bases for formulating relevant standards and specifications.
In summary, the method for measuring the relative tracking index of solid insulating materials needs to comply with the provisions of relevant standards, use appropriate test equipment and test conditions, and strictly follow the test steps. By measuring the relative tracking index, the leakage resistance of solid insulating materials can be evaluated, providing an important reference for product design and manufacturing.
1. Test standard
The test of comparative tracking index usually follows the relevant provisions of the International Electrotechnical Commission (IEC) or national standards (GB), such as IEC 60112 or GB/T 4207. These standards specify the requirements for test methods, test conditions, test equipment and data processing in detail.
2. Test equipment
The test equipment mainly includes a tracking tester, electrodes, electrolytes, timers, etc. The tracking tester is designed according to the simulation test items specified in the relevant standards. It can apply a specific electric field and drip electrolytes at regular intervals to observe and record the tracking time. The electrodes are usually platinum electrodes, and their shape, size and surface treatment must meet the standard requirements. The electrolyte is generally an ammonium chloride solution, and its concentration and dripping speed must also be controlled according to the standards.
3. Test steps
Sample preparation: Cut the solid insulating material into samples of specified size (such as 2mm×5mm×12mm) and perform necessary surface treatment, such as cleaning and drying.
Test condition setting: Under standard atmospheric pressure, the temperature of the test environment is controlled at 23℃±5℃, and the humidity must also meet the standard requirements. Apply a 50Hz sine wave voltage between the electrodes, and the voltage value must be selected according to the standard or the characteristics of the material to be tested.
Apply an electric field and drip electrolyte: Place the sample between the electrodes and apply an electric field. At the same time, drip the electrolyte according to the time interval and drip height specified by the standard.
Observation and recording: Observe and record the tracking of the sample surface, including tracking time, tracking length, etc. When the sample fails due to tracking (such as continuous burning, arc discharge, etc.), stop the test immediately.
Data processing: Calculate the comparative tracking index according to the test data and the method specified in the standard. Generally, the comparative tracking index refers to the ratio of the maximum voltage value (or voltage range) of 5 specimens subjected to 50 drops of liquid without tracking failure and continuous burning to the corresponding value of the reference material.
IV. Precautions
Sample preparation: The shape, size and surface treatment of the sample must meet the standard requirements to ensure the accuracy and comparability of the test results.
Test environment: The temperature, humidity and other conditions of the test environment must be strictly controlled to reduce the impact of external factors on the test results.
Equipment calibration and maintenance: The test equipment must be calibrated and maintained regularly to ensure its normal operation and the accuracy of the test results.
Safe operation: Safety operating procedures must be followed during the test to prevent safety accidents such as electric shock and fire.
V. Application and significance
The measurement of the comparative tracking index is of great significance for evaluating the leakage resistance of solid insulating materials. It can help manufacturers select suitable insulating materials and improve the safety and reliability of products. At the same time, the comparative tracking index is also one of the important bases for formulating relevant standards and specifications.
In summary, the method for measuring the relative tracking index of solid insulating materials needs to comply with the provisions of relevant standards, use appropriate test equipment and test conditions, and strictly follow the test steps. By measuring the relative tracking index, the leakage resistance of solid insulating materials can be evaluated, providing an important reference for product design and manufacturing.