Presentation by Christoph Zekorn at the conference of the "Polymer Testing World Expo 2021" in Essen, Germany
When high-voltage safety systems leave the production plant, they are regularly checked as part of quality assurance. This involves testing them in electrical switch-off tests, in which temperatures of around 150 °C are reached.
After changing the sleeve supplier, the manufacturer reported a high failure rate in the form of self-ignition. The cause of the damage had to be clarified by comparing new sleeves from both suppliers.
Apart from the fact that the resin system is different and processing faults were observed, the flame-retardant (ATH) proved to be unsuitable and was established as the cause of the damage.
The elevated temperatures encountered during application lead to degradation of the ATH, resulting in water formation. The condensation can encourage a renewed current flow and can thus damage the mode of functioning.