In the world of electrical safety testing, the PTI and CTI tracking index tester is a really important piece of equipment. It's like a "safety guard" for electrical devices. Why is it so crucial? Well, it can copy the tough situations that electrical equipment might face during normal use. By doing this, it can find out how well materials can resist tracking leakage, which helps stop electrical problems and safety accidents.

1. Main Standard

First of all, let's talk about the standard. This tracking index test apparatus is mainly designed following the IEC60112 standard. The IEC 60112 is a well - known international standard. It's used to evaluate two important things: the comparative tracking index (CTI) and the proof tracking index (PTI) of solid insulating materials when they're in a humid environment. This standard carefully tells us about the technical needs of the test device, the recipe and concentration of the solution used, the shape and size of the electrodes, how to do the test step - by - step, and how to decide the test results. Besides, it also meets the requirements of other standards like UL746A, GB.T4207, GB4706.1, and TMD 3628 - 92.

2. What is the CTI and PTI?

Now, what exactly are CTI and PTI? CTI, which stands for comparative tracking index, is a number. It shows the highest voltage at which five test samples can go through the test with drops and not have a tracking failure or a continuous flame. It also includes information about how the material behaves when its surface endures 50 drops.

PTI, or Proof Tracking Index, is another number. It's the voltage (in volts) at which five test samples can complete the test with drops without any tracking failure or continuous flame.

3. Working Principle

Next, let's look at how this tester works. The working principle is based on putting a certain voltage and a special electrolyte on the surface of the insulating material. This is like creating a small "simulated world" similar to real - life working conditions, including humidity and dirt. When the voltage is applied, the electrolyte forms a path that can conduct electricity because of the electric field. This makes a leakage current. As the test goes on, the heat from this leakage current slowly breaks down the molecular structure of the insulating material. Then, we can see carbonized marks on the material's surface, which is called tracking leakage. Finally, we can judge how well the material resists tracking by looking at and measuring these marks.

4. Structure of Tracking Index Test Apparatus

The test electrodes are very important parts of the device. They are made up of two electrodes with specific shapes and sizes. Each electrode is (2mm±0.1mm)×(5mm±0.1mm)×(40mm±5mm), at least 12mm long, and has a chisel - edged angle of 30°±2°. Usually, they are made of platinum with a purity of at least 99%. These electrodes make sure the voltage is applied steadily and they touch the material's surface well during the test.

The solutions dripping system is also key. It can control the speed and amount of the solution drops very precisely. This makes sure the test conditions are always the same and accurate. The common solution used is an ammonium chloride solution. There are two types: Solution A with 0.1%NH4Cl and a conductivity of 3.95±0.05Ωm, and Solution B with a conductivity of 1.98±0.05Ωm.

The voltage control system can change the output voltage. This way, it can meet the testing needs of different materials and standards.

Generally, the voltage can range from 100V to 600V.

The test container is where we put the test samples. It's made of insulating materials to keep outside things from affecting the test results.

5. Operation Steps

Before starting the test, we need to prepare the samples. Cut the material we want to test into the right size and shape, and make sure the surface is clean and flat.

Then, we should debug the device. Check if the test electrodes, the solution dripping system, the voltage control system, and so on are all working correctly. Set the test parameters, such as the voltage, the dripping speed, and the amount of the solution.

After that, install the sample. Put the sample in the test container and adjust the contact position and pressure between the test electrodes and the sample surface to get a good electrical connection.

Now, we can start the test. Turn on the device, start dropping the solution, and apply the voltage.

Finally, when the set test time is up or we see obvious marks on the sample surface, it's time to end the test. Turn off the device and save all the test data and records.

6. Application Fields

This tracking tester is widely used in many industries. In the electronics and electrical appliance industry, it checks the insulating materials in things like plastic cases, connectors, and circuit boards. This ensures the electrical safety of products in all kinds of environments.

In power equipment manufacturing, it tests the insulating parts of high - voltage switches, insulators, and transformers. This helps keep the power system running smoothly.

For the automotive manufacturing industry, during the design and production of car electrical systems, it tests different insulating materials and components. This makes cars' electrical systems safer and more reliable.

Even in the aerospace field, it strictly tests the electrical insulating materials of aerospace equipment. This is to make sure the equipment can work safely in extreme conditions.

7. Maintenance Points

To keep the tracking index test apparatus working well, we need to do some maintenance. After each test, clean the test electrodes, the test container, and the solutions dripping system right away. This stops the remaining solution from corroding the equipment.

Regularly check the test electrodes for wear. If we see signs of wear or deformation on the electrode surface, replace them quickly to keep the test results accurate.

Calibrate the voltage system regularly. This ensures the output voltage is accurate and stable.

When storing the equipment, put it in a dry and well - ventilated place. Avoid direct sunlight and a humid environment to prevent damage.

In conclusion, the tracking test device is really important for making sure electrical equipment works safely. It helps a lot in the design, production, and quality control of electrical products. As technology keeps improving, this device will also get better and better to meet the stricter electrical safety standards and market needs.