Creepage distances in PCB internal layers - diyAudio
Go Back   Home > Forums > Amplifiers > Power Supplies

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 20th September 2005, 07:23 PM   #1
diyAudio Member
 
Join Date: Dec 2002
Location: Slovenia
Default Creepage distances in PCB internal layers

Hi,

I need to desigh planar transformer, but I can find no requirements for creepage distances in internal layers of the multilayer PCB. So far I think it is like that:

-if I can prove that multilayer PCB is voidfree, then I can assume solid insulation. Single layer of insulation must be 0.4mm thick for double insulation and 0.4mm FR4 woud break down at 16.5kV (1100V/mil breakdown voltage). I do not know FR4 specification for working (operational) voltage, only for breakdown voltage, so i have no clue what spacing to use between tracks of the same transformer winding.

-if I can not prove that multilayer PCB is voidfree, then I use creepage distance specified for coated PCB.

Can I prove that PCB is voidfree with 100% hipot testing and how high test voltage should be?

I would be grateful for some guidelines.

Best regards,

Jaka racman
  Reply With Quote
Old 20th September 2005, 07:44 PM   #2
Electrons are yellow and more is better!
diyAudio Member
 
peranders's Avatar
 
Join Date: Apr 2002
Location: Göteborg, Sweden
Blog Entries: 4
I have standards at work in this topic but how high voltages do you have in mind?
__________________
/Per-Anders (my first name) or P-A as my friends call me
Tube Buffered Gainclone in work |Thread || Diamond buffer |Thread for the group buy | Wiki
  Reply With Quote
Old 20th September 2005, 08:59 PM   #3
diyAudio Member
 
Join Date: Dec 2002
Location: Slovenia
Hi,

working (operational voltage) for the whole winding would be 450V and 900V, hipot test is 4kV minimum.

I would be also interested in which standard is applicable. I am familiar with IEC(EN)60664, but I have not found anything about multilayer PCB.

Best regards,

Jaka Racman
  Reply With Quote
Old 24th October 2005, 09:19 AM   #4
Electrons are yellow and more is better!
diyAudio Member
 
peranders's Avatar
 
Join Date: Apr 2002
Location: Göteborg, Sweden
Blog Entries: 4
My gut feeling is that you should avoid what your are planning to do. Why don't you consider an ordinary magnetic device with wires instead of etched traces?
__________________
/Per-Anders (my first name) or P-A as my friends call me
Tube Buffered Gainclone in work |Thread || Diamond buffer |Thread for the group buy | Wiki
  Reply With Quote
Old 26th October 2005, 02:11 PM   #5
diyAudio Member
 
Join Date: Dec 2002
Location: Slovenia
Quote:
Why don't you consider an ordinary magnetic device with wires instead of etched traces?

Hi.


I have been using planar transformers from Payton for almost ten years. Reasons are:

-repeatabillity
-relatively low leakage inductance
-low form factor
-low losses
-efficient cooling

It is much like difference between point to point wiring and PCB.

Problem with Payton is minimum quantity and tooling fee, since their range of standard products is small and they do custom designs.

Best regards,

Jaka Racman
  Reply With Quote
Old 26th October 2005, 02:17 PM   #6
diyAudio Member
 
Ouroboros's Avatar
 
Join Date: Dec 2003
Location: Nottingham UK
Unfortunately EN60950 (which has a good section on these requirements) isn't available on line. If all else fails, I could scan the relevant sheets from our paper copy here at work.
  Reply With Quote
Old 26th October 2005, 02:34 PM   #7
diyAudio Member
 
Join Date: Dec 2002
Location: Slovenia
Hi,

thanks, since my field is medical i was not aware that 60950 deals with that. I will look it up.

Best regards,

Jaka Racman
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Cabinet in layers kvk Full Range 22 12th March 2008 08:59 PM
Products certifications, safety requirements (and creepage distance) VT67 Power Supplies 55 2nd August 2007 02:16 PM
Cabinet construction started - additional absorbent internal layers? quickshift Multi-Way 8 26th February 2007 08:08 PM
Splitting sound layers off of a CD? devroger Digital Source 5 17th February 2007 05:22 AM
Peerless CSC and Vifa TC assymmetrical layers of VC windings capslock Multi-Way 21 29th November 2006 12:32 PM


New To Site? Need Help?

All times are GMT. The time now is 07:41 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2