You could use an anti corona coating, in addition to minimising sharp points (blobby solder joints will help).
Try a search for anti corona epoxy
You may need to match the dielectric constants to minimise the voltage stress at interfaces.
Routed air gaps can collect dust and fibres if your enclosure is not sealed, so can arc and spark over time.
Best Regards
David Greig
______________________________
GigaDyne Ltd
Buchan House
Carnegie Campus
Dunfermline KY11 8PL
United Kingdom
t: +44 (0)1383 624 975
www.gigadyne.co.uk
______________________________
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Phil Nutting
Sent: 07 November 2005 18:52
To: [log in to unmask]
Subject: Re: [TN] High voltage breakdown... solutions?
Bill,
I think it was Glyptal. It is a red gooey paint. Most commonly used in HV applications like the back of CRTs.
I used to have a can here, but I think it got tossed with some personel changes.
Phil
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Brooks,Bill
Sent: Monday, November 07, 2005 1:48 PM
To: [log in to unmask]
Subject: Re: [TN] High voltage breakdown... solutions?
Thanks Phil.
The oil was thought of... although not a specific type.
The routed gap idea was thought of too... and also high insulation resistance conformal coating...
The corona ball idea is an interesting method... fixing 'sharp points'
in
the process... Of course a redesign of the old board is the appropriate method...
Didn't Dupont or some other company have a 'corona coating' of some sort back in the bad old days? I think they had some sort of
shellac or something they sold for high voltage applications to deal with things like this...
I just can't remember where I saw it...
Bill Brooks - KG6VVP
PCB Design Engineer, C.I.D.+, C.I.I.
Tel: (760)597-1500 Ext 3772 Fax: (760)597-1510 Datron World Communications, Inc.
_______________________________________
San Diego Chapter of the IPC Designers Council Communications Officer, Web Manager http://dcchapters.ipc.org/SanDiego/
http://pcbwizards.com
-----Original Message-----
From: Phil Nutting [mailto:[log in to unmask]]
Sent: Monday, November 07, 2005 9:50 AM
To: TechNet E-Mail Forum; Brooks,Bill
Subject: RE: [TN] High voltage breakdown... solutions?
Bill,
This is a constant problem that we solved by routing a slot between the two traces. The slot or gap needs to be sufficient
enough to prevent flash over in air. That assumes your board is in air. You could also "sink" the board in a dielectric oil or
Sulfurhexaflouride, but these bring new issues to the product.
Another quick solution would be to hand solder a high voltage "corona ball" along the edge of the etch patterns. Consider the
etched edge of a trace. It is a huge sharp edge. Now if you were to add a blob of solder to make the edge less sharp you may
be able to fix your problem.
Keep in mind there are two issues here, surface tracking and an arc in air. With surface tracking the routed slot works best.
Hope this is of some help.
Phil
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Brooks,Bill
Sent: Monday, November 07, 2005 12:39 PM
To: [log in to unmask]
Subject: [TN] High voltage breakdown... solutions?
It's Monday... had your coffee yet?
I'm trying to gather together some potential solutions to High Voltage breaking over and arcing between traces on board. The
things I know contribute to this are things like, too little spacing between traces on the surface or in the inner layers, sharp
points on traces, board cleanliness or the presence of contaminants between the potential voltages.
It was suggested that conformal coating the boards after a real good cleaning might improve the insulation resistance between
traces, has anyone done this successfully? Do you have any other ideas short of a re-layout of the board that could perhaps
repair a problem like this?
Any ideas are most appreciated.
Bill Brooks - KG6VVP
PCB Design Engineer, C.I.D.+, C.I.I.
Tel: (760)597-1500 Ext 3772 Fax: (760)597-1510 Datron World Communications, Inc.
_______________________________________
San Diego Chapter of the IPC Designers Council Communications Officer, Web Manager http://dcchapters.ipc.org/SanDiego/
http://pcbwizards.com
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with
following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send
e-mail to
[log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to
[log in to unmask]: SET Technet Digest
Search the archives of previous posts at:
http://listserv.ipc.org/archives
Please visit IPC web site
http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or
847-615-7100
ext.2815
-----------------------------------------------------
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with
following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send
e-mail to
[log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to
[log in to unmask]: SET Technet Digest
Search the archives of previous posts at:
http://listserv.ipc.org/archives
Please visit IPC web site
http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or
847-615-7100
ext.2815
-----------------------------------------------------
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with
following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send
e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to
[log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC
web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at
[log in to unmask] or 847-615-7100 ext.2815
-----------------------------------------------------
--
Virus scanned by Lumison.
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-----------------------------------------------------
|
