Commissioning of a Vacuum Plant
A vacuum plant has been commissioned for testing insulation systems of electrical machines in aerospace applications. With this it is possible to investigate the combined influence of reduced air pressure and increased temperature on the insulation strength.
For aerospace applications, there are increased requirements on the insulation strength of the components due to their operation. In the design process of electrical machines, the ambient parameters in particular must be considered to ensure safe operation. Low ambient air pressure and increased temperature increase the risk of partial discharges. These can occur if the so-called critical electric field strength is exceeded locally within the insulation system. The equivalent voltage is called partial discharge inception voltage (PDIV). When the PDIV is exceeded, damage processes occur, which can cause the insulation system to fail within a very short time.
While thermal influences on the PDIV are considered in the design process by empirical safety factors, the standardization does not include a safety factor for low ambient air pressure. In particular, the combined influence of reduced ambient air pressure and increased temperature on the design process of insulation systems is largely unexplored.
As part of the E-SATstart project, this relationship is being researched and applied to an example geometry. The goal is to quantify the influence on PDIV in order to design insulation systems for aerospace applications according to requirements. The data of the vacuum system are listed in the following table:
| Parameter | Wert |
|---|---|
| Adjustable temperature | RT – 140 °C |
| Adjustable air pressure | Ca. 20 mbar – 1013 mbar |
| Internal dimensions of the chamber (WxDxH) | 600 mm x 625 mm x 400 mm |