Pollution Degree Ratings for Power Supplies

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A much less frequent query that TDK-Lambda’s Technical Assist group will get requested is “what's the air pollution diploma of your merchandise?”  It is extremely vital for the protection of the top tools and could be discovered listed within the security certification reviews.

Our merchandise go into a variety of business purposes, from semiconductor fabrication services to off-shore drilling platforms.  The atmosphere that they function in varies dramatically, and a stroll via the service division will present which prospects haven’t paid consideration to air pollution diploma!  By “air pollution” we imply contaminants that might be condensation, water and a wide range of dusts.


The three most important security requirements for power provides (IEC 60950-1, IEC 60601-1 and IEC 61010-1) all name up air pollution diploma classifications, and normally the wording is analogous.

Pollution Degree 1 is the least stringent.  It applies the place there isn't a air pollution or solely dry, non-conductive air pollution.  This not solely applies to purposes like clear rooms, but in addition the place the power provide is positioned in a sealed cupboard or enclosure.

Pollution Degree 2 is just a little more durable, making use of to non-conductive air pollution that with occasional condensation may turn out to be briefly conductive.  Relevant for merchandise utilized in workplace environments, laboratories and take a look at tools.

Pollution Degree 3 you'll discover in harsh industrial and farming, notably with unheated rooms.  Conductive air pollution is to be anticipated, with or with out condensation.

Pollution Degree 4 is outside tools.  Persistent conductivity, rain and even snow is the norm.

May a air pollution diploma 2 power provide be utilized in an out of doors application?  Sure, offering it's mounted in an acceptable enclosure.

When the power provide is submitted to the protection take a look at homes for certification, cautious consideration is paid to distance between parts, pcb traces and the product housing.  The voltage measured say between two traces on a pcb will decide the insulation thickness or creepage/clearance distance.  Creepage is the shortest distance measured on the floor of an insulator; clearance is the shortest distance via the air.  With air pollution, this distance may turn out to be lowered, resulting in the chance shock or failure.  The producer will advise upon submittal what air pollution diploma they need the product evaluated to.  For TDK-Lambda’s ZMS100 collection of AC-DC power provides, air pollution diploma 2 was chosen and due to the product’s 5,000m altitude specification, these spacings had been multiplied by 1.48 in keeping with IEC 60664-1.

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