Anyone has experience on this HUMplug-e product ?
Web page
http://www.21best.com/21_best/electronic/security/video/filters/for_sale_.html
says:
" Simply plug your equipment through this, to cure it of Ground
Loops. Filters out unwanted voltage and current in the ground line
that cause ground loop hum while simultaneously maintaining a solid,
safe ground."
I have experience on many different way on solving ground loop
loop problems in audio/vidoe systems. Practically every other
types of products listed on that page are known to me in details
(I have used similar produicts, know what is inside such items,
even manufactured some quite simlar products). I have written
some material on ground loop solving to
http://www.epanorama.net/do***ents/groundloop/index.html
How this HUMplug-e product works makes me wonder.
Given the specifications (15A current) and a small
size it can't be an isolation transformer.
According the description it keeps the solid
ground connection it just can't be a "cheater" plugs
that just simply cuts ground connection (dangerous
peactice that is not recommended).
My quess that it does some magic on ground connection
so that it stops/reduces the current that can flow on
normal ground loop case, but still lets the ground
connection to be good enough for electrical safely.
I am just wondering how this is done in such what that it
works and meets the electrical code safey requirements.
Anyone has experience on how this is implemented ?
Some of my quesses would be those impklementation
possibilities:
- some common mode coil type construction over all wires
- two parallel diodes (on different directions) wired
between input and output ground connections
(stops current when voltage difference is low but
will pass hort circuitfualt currents at low voltage drop)
Anyone commenting my quesses how this device works ?
Anyone has experience on this ?
One quess is that this HUMplug-e could be based on circuit
similar to Figure 3 - A High Current Safety Loop Breaker Circuit
at web page http://sound.westhost.com/earthing.htm
Description of the web page:
"The loop breaker works by adding a resistance in the earth return
circuit. This reduces circulating loop currents to a very small value,
and thus breaks the loop. The capacitor in parallel ensures that the
electronics are connected to the chassis for radio frequency signals,
and helps to prevent radio frequency interference. Finally, the diode
bridge provides the path for fault currents. The use of a large
chassis mounting (35A) type is suggested, since this will be able to
handle the possibly very high fault currents that may occur without
becoming open circuit. Note the way the bridge is wired, with the two
AC terminals shorted, and the two DC terminals shorted. Other
connection possibilities are dangerous, and must be avoided."
"In the event of a major fault, one (or more) of the diodes in the
bridge will possibly fail. Semiconductors (nearly) always fail as
short circuit, and only become open circuited if the fault current
continues and 'blows' the interconnecting wires. High current bridge
rectifiers have very solid conductors throughout, and open circuit
diodes are very rare (I have never seen a high power bridge go open
circuit - so far at least). Use of the bridge means that there are two
diodes in parallel for fault current of either polarity, so the
likelihood of failure (to protect) is very small indeed."
This circuit installs a circuit consisting of diodes, resistor and
capacitor the grounding wire. Would using this kind of circuit
on groudn path be electrically safe and/or legal in this kind
of application ?
--
Tomi Engdahl (http://www.iki.fi/then/)
Take a look at my electronics web links and do***ents at
http://www.epanorama.net/
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