Notification 635 -– Harmonic Limit Exceeded

CATEGORY

ISSUE / RESULT

FIX / REFERENCE(S)

Information

The limits for one or more  harmonics have been exceeded.

  • Reduce KP and reoptimize the design.

 

For Power Supplies above 25W the standard IEC61000-3-2 defines the maximum allowed individual current harmonics allowed on the AC input.

By lowering the KP of a design you are guaranteeing lower harmonic distortion.

 

Harmonic order (n)

Maximum permissible harmonic current expressed as a percentage of the input current at the fundamental frequency (%)

2

2

3

30•λ *

5

10

7

7

9

5

11≤n≤39 (odd harmonics only)

3

 

* λ is the circuit power factor