Recommendations for testing electric motors: EASA AR100-2025

Within Europe, we talk a lot about standards. But when it comes to electrical testing of electric motors, it remains strikingly quiet.

IONIO also follows developments in the US regarding standards and guidelines—interesting, because they are already several steps ahead there.

There is no clear, practical European guideline that answers questions such as:
– which electrical tests are really required
– when to test: before and after overhaul
– how to define test voltages and acceptance criteria
– how to demonstrably prove electrical reliability

That is exactly where EASA AR100-2025 becomes relevant.

This guideline does not describe electrical testing as a formality, but as evidence:
– insulation resistance and PI for insulation condition
– surge testing for winding integrity
– AC/DC high-voltage testing for dielectric strength
– phase balance, resistance, and impedance

In the absence of a European guideline, AR100 can serve perfectly well as a technical reference framework. Not because it is “mandatory,” but because it works.

The difference compared to the previous AR100-2020 guideline
AR100-2020 says: “These are the tests you must perform.”
AR100-2025 says: “This is how testing contributes to demonstrable reliability.”

That is precisely why AR100-2025 is far more suitable as a practical guideline for Europe, where a unified framework for electrical testing of electric motors is still missing.

Reliability requires clarity.
And clarity starts with knowing what you measure, why you measure it, and what the result actually means.

Reliable motor testing according to EASA AR100 starts with the right equipment. IONIO supplies the MTC2-R7 surgetester for surge and partial discharge testing, and the MotorAnalyzer 3 for dynamic motor analysis. Contact IONIO for advice on your motor testing process.