Transformer Compliance Testing, overheat then humidity treat, then dielectric test?

[JieTan]

Hi guys, I know it states quiet clearly in IEC 60601-1, 2012, section 15.5.1 (overheat) to do dielectric strength test after overheating then the dielectric strength section requires us to do humidity treatment the dielectric strength test.

However, my colleague is of the opinion that after overheating, you go straight to dielectric strength test without humidity treatment. His rational is humidity treatment and overloading are both faults conditions, so subjecting a transformer to both would be a double fault scenario.

I am not sure about humidity treatment been one fault. Can anybody comment on this, and therefore, if the testing order is overheat, the humidity treatment, then dielectric strength test?

Super appreciatea nyone's help

 

[Pads38]

Re: Transformer Compliance Testing, overheat then humidity treat, then dielectric tes

Firstly - welcome to The Cove.

In 15.5.1.1 the tests for overheating are identified and there is a requirement for dielectric strength tests. This is conducted after the short circuit test and the overload test. It is conducted as shown in 8.8.3.

Tests are:
primary - secondary
primary - frame
secondary - frame

This tests for damaged insulations after the 'fault' tests.

Separately, in 15.5.2 there are the tests known as the 'turns/layers tests'. This is another set of dielectric strength tests. As you have correctly identified this set of tests is conducted immediately after humidity pre-conditioning. (Note this test does not apply to transformers operating above 1kHz. See Amendment 1)

The short circuit and overload tests do not specify the need for humidity preconditioning, so dielectric test can be done immediately after these tests.

Note that the humidity treatment is not a 'fault' condition. It is regarded as normal use (perhaps during transport). Your risk analysis will need to address whether the 48hrs@93% is sufficiently rigorous for your device / application.