IEC 61010 Humidity Preconditioning and Condensation

G

George Jameson

I'm attempting to 61010-1 validate a measurement device, and ran into issues with the 6.8.2 and 6.8.3 portion of the standard: Humidity Preconditioning and Solid Insulation testing.

6.8.2, partially excerpted :

The air in the chamber is stirred and the chamber is designed so that condensation does not precipitate on the equipment.

The equipment remains in the chamber for 48h, after which it is removed and allowed a recovery period of 2h under the environmental conditions of 4.3.1, with the covers of non-ventilated equipment removed.
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The test lab indicated that condensation was visible within the device when the test voltages were applied. Is this typical for this test? My understanding is that this test is intended to humidity stress the materials the device is constructed from, but large internal condensation instead stresses the creepage distances along the surface.

What should we do here?

Thanks!
 
O

occounty

Involved In Discussions
Hello,

The Humidity conditioning is for testing the clearances and strength of the solid insulation under the worst condition of humidity conditioning.

Strength of the solid insulation is determined by applying either AC or DC test voltage. Passing criteria for this test is that shall be no flashover of clearances or breakdown of solid insulation.

I do not understand your question. What do you mean by "The test lab indicated that condensation was visible within the device when the test voltages were applied".

Is the testing lab stating that formation of condensation within the EUT is a failure? Well there will be some condensation some visible and some invisible after the humidity conditioning. So what's issue with.

Formation of condensation is not considered as a passing criteria by standard, the tests mentioned in 6.8.3.1 to 6.8.3.3 are. If your EUT is passing those tests you should be good to go.
 
B

blargon

Hello,

If this is a climatic test, some condensation within the chamber device is normal: this would not invalidate the chamber. Climatic chamber design features such as recirculation and sealing from lab environment, vent-trapping to allow moisture to escape from the chamber, help to control moisture levels.

If the requirement is to test at elevated temperature & humidity without condensation on the EUT, consider using a drip shield over the EUT and optimizing the chamber temp / RH ramp.
 
G

George Jameson

Thank you both.

On further examination it appears the test was not done in accordance with the standard, and is being re-done. The 61010 version of this test allows for 2 hours of recovery before the voltages are applied. This time is to allow the condensation that comes out due to the thermal change to evaporate away. The primary purpose of the test is to check the effects of hygroscopic materials. When the test does not include the recovery period, it instead stresses creepage distances by effectively reducing them with the addition of conductive condensate.

This step was unfortunately skipped, which provided a very wet path for the arc to initiate along. Retesting now, fingers crossed.
 
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