What is Tracking Test?

Purpose of the Tracking Test

The tracking test simulates the actual use of household electrical appliances, testing whether conductive material deposited on the insulating material surface by live components of different polarities can cause surface creepage, short circuits, and fire hazards. During use, environmental pollution can cause dirt and moisture to accumulate on the insulating material surface, leading to leakage. This in turn can induce corrosion and damage insulation performance. The test specified in this standard is an accelerated test that simulates extremely harsh conditions to verify whether the insulating material will form tracking. This allows for a rapid assessment of the tracking resistance of solid insulating materials, ensuring product safety under specific environmental conditions.

Scope of Application

Suitable for research, production, and quality inspection of lighting equipment, low-voltage electrical appliances, household appliances, machine tool appliances, motors, power tools, electronic instruments, electrical meters, and information technology equipment. Also suitable for the insulation materials, engineering plastics, electrical connectors, and accessories industries.

Features of the Tracking Tester

1. Programmable Controller Touchscreen + PLC Control;

2. Voltage, start and drain, switch, current, stop, exhaust, and lighting are all controlled on the touchscreen, and test data can be stored on the touchscreen. After the test is completed, the save screen automatically pops up. Enter a name to save the data. All saved data can be retrieved in the historical data.

3. The Tracking Tester displays voltage, fall time, current, fall time, door status, current, and test results in real time.

4. Seven-inch full-color touchscreen;

5. A silent anti-backflow exhaust device is installed on the top to exhaust combustion fumes after the test.

6. Selectable test power range;

7. The Tracking Tester can set the number of injections and injection time;

8. Automatically determines whether the test is qualified;

9. Current overload protection;

10. Safety protection: Automatically indicates door status; and there is no voltage in the test area when the door is open;

11. The Tracking Tester displays the peak current value.

The tracking tester measures the relative resistance of solid electrical insulating materials to electrical tracking when exposed to water containing impurities in an electric field at voltages up to 600V. Tracking can occur under these test conditions when a voltage is applied between a specified set of electrodes placed on the material surface and an electrolyte is dripped between the electrodes at specified intervals. The number of drops required to cause material failure increases with decreasing applied voltage, and below a certain limit, no tracking occurs. While the material exhibits no tracking even at the highest test voltage, varying degrees of corrosion may be present, and the corrosion depth can be measured.

Tracking Tester Precautions

1. The test chamber must be properly grounded to prevent injury from electric shock.

2. When adjusting or clamping samples, always disconnect the power supply to the electrodes.

3. After the test, be sure to drain the solution from the dripping cup and dripping tube, then replace it with clean water and continuously drain the solution. Clean the solenoid valve to minimize corrosion.

The factors that affect this test can be summarized as follows:

① Pretreatment of the Tracking Tester Specimen: While the standard requires the specimen surface to be clean, specimens inevitably accumulate contaminants such as release agent, oil, and dust during manufacturing, transportation, and delivery before final testing. Therefore, cleaning the specimen surface is essential.

② Flatness of the Tracking Tester Test Surface, Test Size, and Thickness: An uneven or scratched test surface will affect the test results. During the test, electrolyte may leak from the edges of the specimen, shortening the combined action time of the electric field and electrolyte, reducing the material's heat capacity, and accelerating heat dissipation, thus affecting the test results.

③Resistivity and purity of the tracking tester electrolyte: Since the platinum black conductivity electrode commonly used in conductivity meters is easily inert, resulting in inaccurate resistivity tests, ensuring that the platinum black conductivity electrode performs well and accurately tests the resistivity of the solution is key. The problem of impurities in the solution is often overlooked, mainly due to the impure distilled water used to prepare the electrolyte.

Tracking Test Analysis

The factors that affect this test can be summarized as follows:

① Specimen Pretreatment

While the standard requires a clean specimen surface, specimens inevitably accumulate contaminants such as release agents, oil, and dust during manufacturing, transportation, and delivery, leading to final testing. Therefore, specimen surface cleaning is essential. Currently, several cleaning methods are used in China for this test:

a. Distilled water b. Dry cotton balls c. Erasers d. Absolute alcohol. Cleaning procedures vary. Distilled water changes the surface moisture of the specimen, while wiping with dry cotton balls makes it difficult to remove grease. Wiping with an eraser can alter the specimen's actual condition. Absolute alcohol is ideal for both removing grease and evaporating naturally. Improper cleaning methods can significantly impact test results.

② Test surface flatness, test size, and thickness

An uneven or scratched test surface can affect test results, leading to deviations. If the specimen dimensions do not meet the 15mm × 15mm × 3mm mark, the electrolyte may flow out of the edges during the test, shortening the combined action time of the electric field and electrolyte. If the thickness is less than 3mm, the material's heat capacity decreases, resulting in faster heat dissipation and affected test results.

③ Electrolyte Resistivity and Purity

Electrolyte resistivity and purity are two important factors in the tracking test. Platinum black conductivity electrodes are commonly used in conductivity meters, which can easily deactivate, leading to inaccurate resistivity measurements. Therefore, a simple method is needed to ensure that the platinum black conductivity electrode performs well and accurately.

The resistivity of the test solution is crucial. However, impurities in the solution are often overlooked, primarily due to impure distilled water used to prepare the electrolyte.

Comparative Tracking Index and Proof Tracking Index

Comparative Tracking Index (CTI): The highest voltage at which five test specimens can withstand 50 drops of water without tracking failure or sustained flame. It also includes information on the material's properties during the 100-drop test.

(PTI): The test voltage at which five test specimens can withstand 50 drops without tracking failure or sustained flame.

Precautions for the leakage tracking test

Precautions for the leakage tracking test are as follows: Do not open the test box or touch the electrodes during the test to avoid electric shock. Special reminder: When doing a 100-200V voltage test, be sure to set the current trimmer to a low position to avoid burning the current fuse and internal resistor due to excessive current caused by voltage increase; before powering on the equipment, the three buttons of "voltage selection", "current adjustment" and "voltage adjustment" must be reset to zero. After each test, the electrodes, test glass platform and micro pump should be cleaned in time. The specific method is to replace the solution in the solution cup with clean water 2-3 times the amount of the test solution, remove the needle, place a solution cup on the glass platform, turn on the power, turn on the handle switch in the box and press the "drip adjustment" button on the panel, turn the stroke length adjustment knob on the micro pump panel to the maximum (100), and turn the stroke frequency selection switch to 100% until all the water in the lower solution cup is discharged from the needle seat; if the edge of the electrode is corroded, it should be re-grinded. The solution cup should be carefully positioned to avoid tipping over, which could cause corrosion and short circuits on surrounding electrical components and metal parts. During the "(Drip Test)" described above, the indicated cup scale may not meet the required specifications, depending on the curvature of the liquid conduit and whether the air in the conduit has been completely expelled. In such cases, the liquid level within the cup will need to be adjusted. The drip conduit must not be bent. The internal parameters of the instrumentation in this test device are factory-set and should not be modified unless necessary (except for pre-set parameters required for testing).