Do you work for (or supply) a publicly traded company in the US? If so, you
may have an interest in the following.
The US Conflict Minerals law (section 1502 of the Dodd-Frank Wall Street
Reform Act) is not a safety issue per se, nor even a product regulatory
issue in the classic sense. It is a
Hi Joe:
If the 150 V DC is generated from the 3.7 V DC,
then a fault between the two circuits will cause
the 150 V DC to stop and become 3.7 V DC.
The Law of Conservation of Energy. There is no
way the 150 V can cause the 3.7 V to increase!
Therefore, there is no need to isolate the 150
V DC
As I previously mentioned, the hi-pot test is for
SOLID insulation.
Presumably, the insulation between the side panels
and the mains circuits is air, or air in series
with solid insulation. So, it should be valid to
test without the side panels.
Merry Christmas!
Rich
On 12/16/2010 06:16,
David,
You have to ask yourself, what would secondary protection be protecting?
As part of your Risk Assessment or circuit Fault Analysis, you must consider
what would happen if the VDR/MOV faulted in a high current or short circuit
condition. If the high current can cause overheating in wiring,
A solution we used years ago involved three elements in series, the VDR,
a gas tube and a fuse.
The gas tube prevented the development of leakage currents as transients
age the VDR.
If the VDR failed, the fuse prevented full line to neutral fault
currents through the gas tube in the event of
I am not positive, but I think this is just a North American glitch
(UL/CSA).I think internationally you could make the justification
that Rich pointed out that it is inherently safe and on these products
skip a final AC hipot. So what if line and neutral are shorted to
ground (other than for
Here is another clunky suggestion. What if you put your Surge Suppressor
circuit after a dual pole circuit breaker that is only energized when
the device is powered up. That way, the VDR is out of the circuit during
the Hipot test, but in-circuit during the Surge Immunity test.
This brings up a
And then there's the EMC surge test, where the equipment must operate
(main fuse not open) after the surge.
James Goedderz
Sr. Principal Engineer-Product Safety
Sensormatic Electronics, LLC
561.912.6378
-Original Message-
From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of
Hi group,
Some safety standards provide an option to reduce overvoltage category of
equipment by using transient suppressors in mains input.
Does anyone know what transient suppressor (VDR, TVS, etc) component standard
is applicable for such suppressors for this application? This is a safety
In message 6.1.0.6.2.20101215231732.01cdb...@pop.randolph-telecom.com,
dated Wed, 15 Dec 2010, Joe Randolph j...@randolph-telecom.com writes:
Rich's question about what the potential current path would be has
bothered me as well. I'm not sure what sort of scenarios to test for,
but there may
Where is the loop for the current to flow!
If the person is part of that loop, there migth be some questions to answer!
I have no problems holding onto a few million volts,
tho' grounding might be a shocking experience.
If the freq is low enough to avoid being the antenna, no / little
Rich, Gary, Brian:
Thanks for your comments and questions. This is very helpful.
Just to clarify, I'm not concerned about the isolation barrier between the
high voltage circuit and the surface of the LCD screen. I'm concerned
about having to provide isolation between the high voltage circuit
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