Re: [8023-POEP] 802.3af Isolation 33.4.1
Hi David,
Yes you are correct this was the reason for excluding the 2250Vdc
option, however it is worth checking it again since technically it
doesn't make sense.
Checking 1500Vac 50-60Hz and checking with 2250Vdc is technically the
same unless the EN60950 wish to check the ac current through the
capacitors and insulation which can not be done with DC?
Yair
-----Original Message-----
From: owner-stds-802-3-poep@xxxxxxxx
[mailto:owner-stds-802-3-poep@xxxxxxxx] On Behalf Of David Law
Sent: Thursday, April 21, 2005 11:30 PM
To: STDS-802-3-POEP@xxxxxxxxxxxxxxxxx
Subject: Re: [8023-POEP] 802.3af Isolation 33.4.1
Hi Bob,
I had a look through the comment database and I would have thought that
comment #88 on page 22 would be of the most interest
[http://www.ieee802.org/3/af/comments/d4.0/P802_3af_D4_0_all_final.pdf#P
age=22].
It seems to be saying that subclause 6.2 of IEC 60950-1 only includes
two
tests, a AC test and a impulse tests, and the suggestion therefore that
subclause 33.4.1 should be aligned to this. The text in the response
seems
to indicate acceptance of this as it doesn't list the DC test.
Best regards,
David Law
> From: Lappin, Bob <rlappin@xxxxxxxxxxxxxxxxxxx>
> Date: Apr 21, 2005 5:09 PM
> Subject: Re: [8023-POEP] 802.3af Isolation 33.4.1
> To: STDS-802-3-POEP@xxxxxxxxxxxxxxxxx
>
> David,
> Thanks for your reply. I searched the comments document and found
> several references to paragraph 33.4.1, but nothing regarding the
> deletion of the 2250VDC testing option.
> Who should I contact regarding the approved standard IEEE Std
> 802.3af-2003 DTE Power via MDI?
> I respectfully ask the IEEE 802.3 Power over Ethernet plus Study Group
> to consider adding the 2250VDC to the list of options for electrical
> strength testing.
> Regards,
> Bob Lappin
> -----Original Message-----
> From: owner-stds-802-3-poep@xxxxxxxx
> [mailto:owner-stds-802-3-poep@xxxxxxxx] On Behalf Of David Law
> Sent: Thursday, April 21, 2005 3:57 AM
> To: STDS-802-3-POEP@xxxxxxxxxxxxxxxxx
> Subject: Re: [8023-POEP] 802.3af Isolation 33.4.1
> Hi Bob,
> While I cannot give you an official answer, as a personal observation
I
> would state that as far as I am aware there have been no changes to
> subclause 33.4.1 since the approval of IEEE Std 802.3af-2003.
> If you are interested in the background to the development of this
> subclause you may want to review the IEEE P802.3af DTE Power via MDI
> Task Force web archive [ http://www.ieee802.org/3/af/index.html]. As
> another personal observations, I do seem to recall that there was a
lot
> of work on this subclause during the devolvement of draft D4.1 in
> particular. I would therefore suggest looking at the comment and
> responses database for D4.0 [
> http://www.ieee802.org/3/af/comments/d4.0/P802_3af_D4_0_all_final.pdf
]
> and searching the file for '33.4.1'.
> And finally, before the Chair of this Study Group has to remind us
all,
> to quote the reflector welcome message 'The IEEE 802.3 Power over
> Ethernet plus e-mail reflector is provided to the members of the IEEE
> 802.3 Power over Ethernet plus Study Group for the benefit of moving
the
> work of the Study Group forward.' I will therefore note that this
> question relates not to the IEEE Power over Ethernet plus Study Group,
> but instead to the approved standard IEEE Std 802.3af-2003 DTE Power
via
> MDI.
> Best regards,
> David Law
>
> > From: Lappin, Bob <rlappin@xxxxxxxxxxxxxxxxxxx>
> > Date: Apr 20, 2005 7:59 PM
> > Subject: [8023-POEP] 802.3af Isolation 33.4.1
> > To: STDS-802-3-POEP@xxxxxxxxxxxxxxxxx
> >
> > I would like to know the reasoning for the change to the Isolation
> > requirements in paragraph 33.4.1.
> > Previously, 2250VDC was an acceptable test option. That option is
no
> > longer shown in the 802.3af specification.
> > The MDI interface will typically have a capacitive path to frame
> > ground to attenuate common mode noise. This capacitance will
conduct
> > AC current up to as much as 30mA during the electrical strength
test.
> > Could someone please explain the reasoning for not allowing the
> > 2250VDC electrical strength test?
> > Thanks
> > Bob Lappin
> > Tyco Electronics