Dielectric strength
Laboratory > Electricals
| Dielectric strength EN60065, EN60204-1,EN60335-1,EN60598-1,EN60601-1,EN60950,EN61010-1,CE | |
Most polymers are electrical insulators, since the outer electrons of the atoms are located, forming covalent bonds and do not give rise to electric current when they are subjected to an electric field. The dielectric strength test is a mandatory test and required by multiple standards, and is one of the essential tests for CE marking. The dielectric strength meter applies high voltage for a programmable time between the mass and determined the leakage current and ruling whether Pass or No Pass, based on the limits established in said leakage current. The tests of dielectric rigidity, are usually with alternating voltage, although there are also equipment in DC. When the electric field exceeds 100 KV in the polymers an electrical discharge is produced, that is to say, the dielectric rupture is caused and the material becomes conductive with the consequent deterioration. The value of the intensity of the field at which the rupture occurs depends on the thickness of the sample, which is why it is described through the so-called dielectric strength, which is expressed in KV per unit thickness, usually cm. The dielectric strength depends on the imperfections present in the material, as the thickness of the sample increases, the probability of defects increases and therefore the dielectric strength decreases, for the same reason the samples submitted to mechanical loads may have lower values than the Dielectric strength. Tracking index test procedure according to IEC60112 In a plastics material plate, 2 electrodes are applied with an adjustable test voltage between 100 and 100 KV. 50 drops of a water solution with 0.1% ammonium chloride are applied between the electrodes and gradually increased. The fault criterion is a cutting current ≥0.5 A for a time> 2s. The thickness of 3 mm is considered representative of the performance of the material in any thickness. |  |
Tracking index test procedure according to IEC60112 | |
The comparative tracking index or CTI is used to measure the electrical cutting properties (tracking) of an insulating material. It is an electrical fault on the surface of an insulating material in an initial exposure to the heat of the original insulator, which produces more current flow, more heat and, finally, complete failure. Expressed as a voltage that causes tracking after 50 drops of 0.1% ammonium chloride solution |  |