Power supply fails in EFT and SURGE TEST

[Nicholas]

surge test

My power supply failed while doing EFT (IEC 61000-4-4) and SURGE (IEC 61000-4-5) tests. I want to place a MOV across the LINE and NEUTRAL. Should it help? Have problem in varistor selection.

 

[Iceskater]

eft on power supply

you can place a varistor before and after EMI filter at the input of your power supply . Check technical notes of EPCOS and LITTLEFUSE for choosing the right varistor.

regards,
Iceskater

 

[som_raparty]

what is surge testing

hi
u can place a mov across the line- neutral, and neutral -earth ( do not connect between line to earth) and if proper clearance is given between the routing on the pcb the surge test will pass. and even i can suggest like the differential chokes at input will help(some may disagree) as of my practical experience.....

for eft try have a good earth connection for u the unit and u can also try by inc the value common mode choke . it may help u

bye
som

 

[navanee]

power supply surge test

Hi,
use transient voltage suppresors like SMBJ series from Fairchild Semiconductors.

regards
Navanee

 

[ada_el]

ferrite beads in eft tests

Hello,
the suggested mitigations are really useful for Surge, but for the electrical fast transients (EFT) you should put at the very first entrance of disturbance some Transil diodes, which provide high overvoltage protection by clamping the disturbance.
See e.g. this link for details

https://www.pci-card.com/p6ke12ca.pdf

regards
Ada

 

[glucamaf]

what is eft in power testing

For EFT Burst could be useful to provide some ferrite bead on the controller where disturbance could influence regulation.
Then you can insert other than the input chokes even some polypropylene capacitors (common mode and differential mode).
You have also to observe if common mode or differential mode test cause most fails to your device....this can help you to strenght the proper circuit part.

 

[rvionics]

power supply filter eft

Use of tranzorb after EMI Filter should help out. Also try to increase the EMI inductor.