Interturn short-circuit
As interturn (a summary of the words winding and short-circuit ), a defect in electric machines referred to, in which the usually by an insulation, such as a paint or crepe paper insulation -separated wire turns of a winding having another electrical contact.
A winding short can be caused by processing incorrectly insulated winding wires or thermal overload. In the case of switched-mode power supplies and high-voltage transformers, the insulation can also be damaged by partial discharges or dielectric heat loss. Interturn faults lead to local heating (a short-circuited winding is created) and to total transformer failure.
When analyzing faults on failed transformers, it is not easy to prove an interturn fault . Often an overheated area (dark discoloration of the insulating material , in extreme cases charred cast resin ) and sometimes a melted winding (broken conductor and copper beads) can be discovered. It is difficult to conclude that this fault pattern was a winding short, and it is even more difficult to answer the question of “why”.
Interturn fault testers are used for quality control or for fault diagnosis. Based on the quality of the inductance of the winding, these determine whether there is an interturn fault.
See also
literature
- A. Senner: Electrical engineering. 4th edition. Verlag - Europa-Lehrmittel, 1965
- Rudolf Huttary: Successfully repairing household electrics and electronics yourself. 3rd edition, Franzis Verlag GmbH, Poing, 2001, ISBN 3-7723-4803-3
- Josef Eiselt: Troubleshooting electrical systems and devices. 2nd edition, Richard Pflaum Verlag KG, Munich, 1976, ISBN 3-7905-0243-X