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Harmonics on RDR194 Question on Class D limits

Posted by: schriekd on Wed, 07/27/2011

Hi

I was studying RDR-194 and found something I cannot explain:

According to the IEC, Lighting Equipment (Class C equipment) below 25W should meet the harmonics limits valid for Class D equipment.

This table tells me that for example the 3rd harmonic has a max permissable harmonic current of 3.4mA/W (table attached)

Your graph shows a limit value of about 95mA @ 115VAC (page 26 RDR-194; graph attached)

As this is a 14W PSU I cannot explain this high limit.

Can you explain?

Thanks,

Don Schriek
Avnet Abacus

Files

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Table 3 Class D.jpg 708.8 KB
Graph class D.jpg 1.8 MB