RE: IEC 60950-1 2nd Ed

[email protected] Tue, 11 Oct 2005 13:27:00 -0400

This is a multi-part message in MIME format.

John,

Thanks for this clarification.  I strongly agree that the DC hipot
provision should never be excluded.   There are far too many products
out there that simply cannot be tested otherwise.


-Doug



Doug Powell, Staff Engineer
Corporate Compliance Dept.
Advanced Energy Industries Inc.


From: John Woodgate [mailto:[email protected]] 
Sent: Tuesday, October 11, 2005 6:12 AM
To: [email protected]
Subject: Re: IEC 60950-1 2nd Ed

Doug Beckwith <[email protected]> wrote (in 
<[email protected]>) about 'IEC 
60950-1 2nd Ed', on Tue, 11 Oct 2005:
>I just read an article on IEC 60950-1 2nd edition in Compliance 
>Engineering, and I was wondering if the standard has actually been 
>released.

 From the public part of the IEC web site:

IEC 60950-1: work in progress

IEC 60950-1 Ed. 2.0 B BPUB [Being Published]
Information Technology Equipment - Safety - Part 1: General requirements

>
>One one of the changes I read about was that DC Hipot testing is no 
>longer allowed. Can anyone confirm that this requirement has changed in

>the new standard, and if so, does anyone know the rationale for this?

It does not appear to be so. Part of clause 5.2.2 of the FDIS says:
QUOTE
Unless otherwise specified elsewhere in this standard the insulation is 
subjected either to a voltage of substantially sine-wave form having a 
frequency of 50 Hz or 60 Hz, or to a d.c. test voltage equal to the peak

voltage of the prescribed a.c. test voltage.
ENDQUOTE
However, the standard is very complicated (can you say 'Byzantine'?), so

the allegation may not be entirely unfounded.
>
>This has a huge impact on the testing of power supplies that have Y 
>caps to ground. It would in effect require disconnection of any caps to

>ground, and this would dramatically impact production line testing.

OTOH, that would avoid over-stressing the Y-caps.
-- 
Regards, John Woodgate, OOO - Own Opinions Only.
Deadlines are 90% of deadliness.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

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Title: RE: IEC 60950-1 2nd Ed

John,

Thanks for this clarification. I strongly agree that the DC hipot
provision should never be excluded. There are far too many products
out there that simply cannot be tested otherwise.

-Doug

Doug Powell, Staff Engineer
Corporate Compliance Dept.
Advanced Energy Industries Inc.

-----Original Message-----
From: John Woodgate [mailto:[email protected]]
Sent: Tuesday, October 11, 2005 6:12 AM
To: [email protected]
Subject: Re: IEC 60950-1 2nd Ed

Doug Beckwith <[email protected]> wrote (in
<[email protected]>) about 'IEC
60950-1 2nd Ed', on Tue, 11 Oct 2005:
>I just read an article on IEC 60950-1 2nd edition in Compliance
>Engineering, and I was wondering if the standard has actually been
>released.

From the public part of the IEC web site:

IEC 60950-1: work in progress

IEC 60950-1 Ed. 2.0 B BPUB [Being Published]
Information Technology Equipment - Safety - Part 1: General requirements

>
>One one of the changes I read about was that DC Hipot testing is no
>longer allowed. Can anyone confirm that this requirement has changed in

>the new standard, and if so, does anyone know the rationale for this?

It does not appear to be so. Part of clause 5.2.2 of the FDIS says:
QUOTE
Unless otherwise specified elsewhere in this standard the insulation is
subjected either to a voltage of substantially sine-wave form having a
frequency of 50 Hz or 60 Hz, or to a d.c. test voltage equal to the peak

voltage of the prescribed a.c. test voltage.
ENDQUOTE
However, the standard is very complicated (can you say 'Byzantine'?), so

the allegation may not be entirely unfounded.
>
>This has a huge impact on the testing of power supplies that have Y
>caps to ground. It would in effect require disconnection of any caps to

>ground, and this would dramatically impact production line testing.

OTOH, that would avoid over-stressing the Y-caps.
--
Regards, John Woodgate, OOO - Own Opinions Only.
Deadlines are 90% of deadliness.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

-
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Instructions: http://listserv.ieee.org/listserv/request/user-guide.html

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Scott Douglas [email protected]
Mike Cantwell [email protected]

For policy questions, send mail to:

Jim Bacher: [email protected]
David Heald: [email protected]

All emc-pstc postings are archived and searchable on the web at:

http://www.ieeecommunities.org/emc-pstc