The tangent of delta, also called tan delta is a test which is used to determine how much the insulation of certain types of cable has deteriorated. All types of materials used as insulation for these cables, usually medium to high are affected by different conditions, which is why they are so carefully evaluated before being installed. For instance, one type of material may be more affected by being exposed to the air or the sunlight.
Others can be affected by excessive moisture that they are often sitting in. For some cables, moisture might build up in the area above or below them, while in others –the cable might be in the moisture itself. Eventually, small cracks may form in the surface of the cable.
The problem with the small cracks and breaks on materials that are meant to form the insulation around a cable of any type is that they can disrupt the way that power travels through them. The tan delta test is used to determine how much deterioration is going on and whether there can be a repair made to the material or if the entire cable needs to be replaced. The tan delta test will show that a new cable, one that does not have any breaks or damages, has good levels of insulation and has no loss of conducted power. In addition, the energy will travel at a nearly perfect ninety degree angle.
Once the moisture starts creeping in to the material, it can cause serious damages and may even make it unsafe to be close to it. In the testing, the angle will be greatly decreased which means that either all or part of the cabling system will have to be repaired or replaced whichever is safest, fastest and most cost effective. Never proceed with a repair or modification if you are not familiar with the methods and the safety rules.
Sorbothane, as a thermoset, polyether based polyurethane material, can be used for these cables, especially for cables in higher moisture situations. It has a higher tan delta which means that it will give a better, overall material performance and can also be used to your best advantage for shock and vibration. That can make the cable last longer and will allow it to perform far better as well as increasing its safety rating in the process.
The test for tan delta cannot always tell exactly where a problem is located- especially if it is very small cracks or other types of damage or it is only located in a small section of a very lengthy cable. The decision can be made however, whether it is time to replace it or to do further testing to increase its conductivity and safety levels. Because the tan delta testing is employed for higher voltages, it is important to know what your best bet is for repairs or replacement and to always proceed with care and caution. It is also important not to make stop gap repairs to save a little bit of money.
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