Hi John,
Regarding all singing and dancing mains plug interface products
Several months ago a colleague returning from USA proudly presented a
universal travel plug adaptor. Not the same one in your link, but a
different one. This design was based on sliding out the plug connection you
David Heald hea...@symbol.com wrote on 06/02/2003 11:51:50 AM:
Most UPS's use a stepped approximation of a sine wave when in battery
mode. While most switching supplies don't care (and are the intended
loads for these UPS's), surge suppressors can cause real issues - It has
something
This is a multi-part message in MIME format.
So much for extension cords. I assume the UPS manufacturer claims his
product is unsuitable for use with all computer products containing surge
suppressors.
Bob Johnson
ITE Safety
Title: RE: Surge Suppressors on a UPS
So much for extension
Dear EMC-PSTC colleagues;
I mentioned off-list to Ed Price that almost all of the UPS from Tripplite
are in fact back up rather than uninterruptible; they perform a switch
from conditioned line power to inverter power in the event of an AC main
failure. This means that they may produce
Chris Maxwell wrote:
Fred,
Maybe you're right. Do UPSs protect against lightning surge?
Your question resolves into two issues: 1) Marketing Hype 2) Reality
1) I have seen some marketing hype that says their UPS will do everything to
protect your system and wash the windows while it is
Brian -
Read 1.4.12.2 for an explanation of what is meant by a
temperature dependent design.
Per 1.4.12.1, Tma is your product's maximum rated operating
ambient, Tamb is the ambient temperature the testing is
performed in. If your product is only intended for use in a
25C ambient and the
Chris Maxwell wrote:
To me, this whole thread begs the question: Why not put the surge
supressor in front of the UPS?
A lot of us have relied on full-time UPS's to stop transients. But the bit
about a UPS itself producing large enough ones to trigger suppressors, that
is worrisome.
Fred,
Maybe you're right. Do UPSs protect against lightning surge? I know that
they protect against low frequency, low magnitude voltage dips and surges.
However, I'm unsure of their ability to protect against lightning surge.
If the UPS is specified by its manufacturer to protect against
Ed - You were asking about output power quality standards for UPS, and while
I don't know the current correct answer (maybe someone from a UPS company
can help us), here are 3 standards that all cover UPS performance:
1. EN50091-3
2. IEC62040-3
3. IEC 146-4
I suspect all 3 are the same document
Mr Hughes and Mr Tarver
Thanks for your replies. I probably spammed the members with poor wording.
When a device (component power supply in this case) requires (as per
conditions of acceptability) a certain air flow, for specified combination of
output power and/or ambient temperature, I
I don't believe there are any power quality requirements imposed on
inverters except those specified by buyers (in the USA, anyway). You can
still buy square-wave inverters, after all, and the modified sine wave
could be called Chock Fulla Harmonic power. Harmful interference is a
limitation, but
I disagree. One assumes some degree of surge suppression since suppression is
touted as a UPS
feature. Therefore your question is moot.
Fred Townsend
Chris Maxwell wrote:
To me, this whole thread begs the question: Why not put the surge supressor
in front of the UPS?
Chris Maxwell |
Brian,
I think that my Email of 30/4/2003 should answer your questions. In regard
to your second substantive para, you will see that it is not always required
to test at the highest ambient temperature. An extract is below...
Richard Hughes
Are you REQUIRED to conduct heating tests
To me, this whole thread begs the question: Why not put the surge supressor
in front of the UPS?
Chris Maxwell | Design Engineer - Optical Division
email chris.maxw...@nettest.com | dir +1 315 266 5128 | fax +1 315 797 8024
NetTest | 6 Rhoads Drive, Utica, NY 13502 | USA
web www.nettest.com |
Most UPS's use a stepped approximation of a sine wave when in battery
mode. While most switching supplies don't care (and are the intended
loads for these UPS's), surge suppressors can cause real issues - It has
something to do with capacitive overload of the output circuits.
And for the
Hi Vic,
I am not sure of the reduction that was done to reach the formula stated by the
RS report [SQRT(Po x R)/D], but the root of the formula must come from the
relationship for electric field strength:
E=SQRT(Zo*Pd) where Zo is the wave impedance and Pd is the power density of
the
Good People
Clause 1.4.12.3 of this standard specifies that ..amount of heating or
cooling is not designed to be dependent on ambient temperature... does not
seem relevant, because the standard requires you to find the worst-case test
conditions for evaluation of the component.
And because of
I read in !emc-pstc that michael.sundst...@nokia.com wrote (in
57a26d272f67a743952f6b4371b8f81101e42...@daebe007.americas.nokia.com)
about 'Surge Suppressors on a UPS' on Mon, 2 Jun 2003:
I also don't understand the prohibition of an extension cord. Maybe
this is a legal issue, as I
Kevin:
I understand the position you are in, several years ago when I was working for
Mitel Corporation, a customer asked us to test to an ESD specification that
they had written, it was unique for their location in the world. To have to
design a product to comply with such requirements when
Hi Folks
Don't know if you have seen the rather tongue-in-cheek TV ad floating around
on European Satellite TV for (something like) an universal computer
interface adapter (with USB, telephone, Serial port etc., etc., etc as one
single unit)?
However, for the equivalent in mains plugs see
Ed, I also hate it when I get ambushed.
In the matter of the extension cord: I guess to lessen their liability they
don't want any extra voltage drop from a cord?
I also agree, why would I hook up a UPS that could fry my equipment with a
switching event?
When you find out let me know, as
Hello Group,
Does anybody have a clue where I could locate User Manuals for following HP
Models,
1. HP 6655A (System DC Power Supply - 0-120V/0-1A)
2. HP 6632A (System DC Power Supply - 0-20V/0-5A,100V)
Thanks in advance.
Harpreet Sidhu
This message is from the IEEE EMC Society Product
Hi,
The following formula was stated in a report covering Radiated Spurious
Emissions:
Field Strength = SQRT(Po x R)/D
Where R was given as 50ohms and D as 3 metres.
Can someone please give me some background to the formula?
Many thanks
Vic Gibling
This message is from the IEEE EMC
Hi Group!
Last Friday, I got ambushed in a meeting. I hate it when that happens!
A question was asked about whether it's OK to put a surge suppressor on the
output of a UPS that is supplying power to some expensive equipment. I opined
that I didn't think it should be necessary, but that it
Dear Group,
We have a client who demands levels of ESD protection well beyond what any
of our product norms call for and to test using their own (unique) test
methods. Their standards were clearly written more than a decade ago
(probably two) and I would like to gently show them that perhaps it
Dear All,
I will appreciate your opinions concerning the following:
1. RTTE Radio standards include for products having an integral
antenna, a radiated power/ spurious test (EIRP), based on the substitution
antenna method.
2. The final test result is:
signal
Dear all,
According to Section 4.1.3 Voltage probes of ANSI C63.4, A voltage probe
may be used for radio-noise voltage measurements when measurements are
made at a user's installation (see 5.6) or when the ac current level
exceeds the current-carrying capability of commercially available
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