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Insulation Lifetime Analysis

A common question that we are asked is whether it is possible to evaluate the lifetime of an insulation system. This is challenging as in a real application a system sees a diverse set of stress factors that are difficult to replicate in the laboratory. As such, mush of the lifetime analysis that can be performed is necessarily worst-case.

As an example of the complexity of lifetime analysis, thermal endurance is typically evaluated by testing the ability of a material / component to withstand a specific voltage following a period of ageing at high temperature (and in many cases mechanical vibration). This is a test well suited to components that operate at a near consistent temperature for prolonged periods of time but care needs to be taken in applying test results to situations where equipment is thermally cycled, spending lower periods of time at the expected maximum temperature.

In a similar way, electrical endurance testing in which a component is exposed to partial discharge should not see the results extrapolated to voltages below the partial discharge inception level. Further complexity exists as partial discharge levels vary as a function of environment (e.g. pressure), inverter topology and frequency.

As is common in testing, the use of simple component level tests (such as motorettes) can offer the chance to assess multiple design options and compare their likely relative lifetimes when used in a specific application.

At aerospaceHV we can work with you to determine the best way to assess the likely failure modes of your insulation system and, as a result, propose test techniques that will judge the likely lifetime of the insulation system.