MOTM

more power questions...

Isn't having two surge protectors plugged into the same outlet (or 
the same circuit for that matter...  or the same house...) the same 
as havign them daisy chained?  Maybe not in the distant examples, but 
the MOV is parallel to the outlet, so what's the difference between 
having a strip plugged into another strip and having two strips 
plugged into each other?  either way, there are going to be two sets 
of MOVs running across the lines.  Is the significant thing here the 
actual physical/electrical distance between the MOVs?  So having 
essentially two surge protectors plugged into my no-surge-protection 
splitter is ok, even though it seemes electically identical to having 
two surge protectors daisy chained?

Also, clipping the blue, cap-like thing out of my strip is ok, 
right?  Arrgh!  Again, I hate to spam, but I don't think I'm the only 
one here to wonder about this.  Anyone else come to the same 
conclusion here?

And more on-topic, exactly what is "star ground?"  I don't quite get 
why you'd need to run two ground lines to each module.  'splain?  I'm 
not 100% inept, so some techno-jargon is ok, but don't go too 
far.  ::grin::

-Geoff

---- Original Message -----
Isn't having two surge protectors plugged into
the same outlet (or the same circuit for that matter...

--LH--
1 - I am no engineer.  2 - Paul's comments about series power strips was the
first I had really hear anyone say this was a bad idea.  He will have to
"splain it to Lucy" and the rest of us.  Personally, I don't care for a
varistor type protection period.  I don't think they offer enough protection
to be worth the trouble anyhow.  I think some others on the list have
offered some suggestions for professional conditioning equipment.  That is
all proabably worthwhile.  I think getting any protection out of the cheap
"surge protector" power strips is just wishful thinking.  I thing varistors
are a fire hazard myself.  Failure mode is meltdown.  I do know that.  I
have sent more than one on fire at work.  BTW, setting things on fire is
part of my job.

---- Original Message -----
Also, clipping the blue, cap-like thing out of my strip is ok,
right?  Arrgh!  Again, I hate to spam, but I don't think I'm the only
one here to wonder about this.  Anyone else come to the same
conclusion here?

--LH--
That would be my initial suggestion.  But, I have to disclaim my advice as a
non-professional.

---- Original Message -----
And more on-topic, exactly what is "star ground?"

"Star" refers to a wiring arrangement and it can describe more than grounds.
To "star" wire anything is to bring all wired to a common point (or as close
as practical).  This is opposed to a "buss" or "daisy chain" type
arrangement when the furst section of wire out of the power supply has all
the current of each downstream device (and the associated noise).  Ever
wonder why Paul recommends # 14 wire to get from the power supply to his
distribution boards?  Certainly it is not the ampacity requirement.  The
larger the wire, and shorter the distance, between the PS and the
distribution board (less ohms, or fractions of ohms in this case) the closer
the arrangement looks like a true star with modules not "sharing" a common
path to ground.

---- Original Message -----
I don't quite get why you'd need to run two ground lines to each module.

--LH--
Short answer, lower noise.  Better answer will need to come from Paul.

Larry H

>2 - Paul's comments about series power strips was the
>first I had really hear anyone say this was a bad idea.  He will have to
>"splain it to Lucy" and the rest of us.

I'll take his word for it but I would like to hear more about exactly what
sort of horrible interactions occur. I was hoping he'd say more but I guess
he's busy designing stuff.


While we're at it perhaps someone can explain how to make my commode stop
shaking the whole house like a jackhammer every time I flush it. It starts
when the tank is almost full and carries on for several minutes.
("oscillatin' like a sieve" as they used to say at ComSonics).


>Personally, I don't care for a
>varistor type protection period.  I don't think they offer enough protection
>to be worth the trouble anyhow.  I think some others on the list have
>offered some suggestions for professional conditioning equipment.  That is
>all proabably worthwhile.  I think getting any protection out of the cheap
>"surge protector" power strips is just wishful thinking.  I thing varistors
>are a fire hazard myself.  Failure mode is meltdown.  I do know that.  I
>have sent more than one on fire at work.  BTW, setting things on fire is
>part of my job.

I guess it's another case of "you get what you pay for" and "it's better
than nothing". I always buy the cheapest power strips at Walmart, the ones
that have "this is not a surge protector" in big letters on the package
(and a cord about two feet long).

I used to repair cable TV amplifiers back in the mid eighties when none of
the manufacturers had ever heard of "surge protection" other than sticking
a few ionized cannisters here and there. The company I worked for made
their own transient snubbers out of a triac and a couple of other
components (they ripped off the idea from another company). The normal
warranty for repairs was 90 days but for an extra fee the customer could
get a one year warranty--which was nothing more than a different-colored
sticker and one of those gadgets installed. Funny how "one year" repairs
almost never came back in less than a year...


>---- Original Message -----
>Also, clipping the blue, cap-like thing out of my strip is ok,
>right?  Arrgh!  Again, I hate to spam, but I don't think I'm the only
>one here to wonder about this.  Anyone else come to the same
>conclusion here?
>
>--LH--
>That would be my initial suggestion.  But, I have to disclaim my advice as a
>non-professional.

As I'm sure Paul will say, "What? There aren't THREE of them in there??"

I remember Steve Ciarcia going over the whole subject in his Circuit Cellar
column years ago--after he got hit by lightning. He stuck MOV's all over
the place, but I'm sure there's better stuff by now.
-- 

Terry Bowman, KA4HJH
"The Mac Doctor"

again, guys, a lot of this is explained at www.brickwall.com

-mark


At 01:14 AM 12/12/01 -0500, you wrote:

> >2 - Paul's comments about series power strips was the
> >first I had really hear anyone say this was a bad idea.  He will have to
> >"splain it to Lucy" and the rest of us.
>
>I'll take his word for it but I would like to hear more about exactly what
>sort of horrible interactions occur. I was hoping he'd say more but I guess
>he's busy designing stuff.
>
>
>While we're at it perhaps someone can explain how to make my commode stop
>shaking the whole house like a jackhammer every time I flush it. It starts
>when the tank is almost full and carries on for several minutes.
>("oscillatin' like a sieve" as they used to say at ComSonics).
>
>
> >Personally, I don't care for a
> >varistor type protection period.  I don't think they offer enough protection
> >to be worth the trouble anyhow.  I think some others on the list have
> >offered some suggestions for professional conditioning equipment.  That is
> >all proabably worthwhile.  I think getting any protection out of the cheap
> >"surge protector" power strips is just wishful thinking.  I thing varistors
> >are a fire hazard myself.  Failure mode is meltdown.  I do know that.  I
> >have sent more than one on fire at work.  BTW, setting things on fire is
> >part of my job.
>
>I guess it's another case of "you get what you pay for" and "it's better
>than nothing". I always buy the cheapest power strips at Walmart, the ones
>that have "this is not a surge protector" in big letters on the package
>(and a cord about two feet long).
>
>I used to repair cable TV amplifiers back in the mid eighties when none of
>the manufacturers had ever heard of "surge protection" other than sticking
>a few ionized cannisters here and there. The company I worked for made
>their own transient snubbers out of a triac and a couple of other
>components (they ripped off the idea from another company). The normal
>warranty for repairs was 90 days but for an extra fee the customer could
>get a one year warranty--which was nothing more than a different-colored
>sticker and one of those gadgets installed. Funny how "one year" repairs
>almost never came back in less than a year...
>
>
> >---- Original Message -----
> >Also, clipping the blue, cap-like thing out of my strip is ok,
> >right?  Arrgh!  Again, I hate to spam, but I don't think I'm the only
> >one here to wonder about this.  Anyone else come to the same
> >conclusion here?
> >
> >--LH--
> >That would be my initial suggestion.  But, I have to disclaim my advice as a
> >non-professional.
>
>As I'm sure Paul will say, "What? There aren't THREE of them in there??"
>
>I remember Steve Ciarcia going over the whole subject in his Circuit Cellar
>column years ago--after he got hit by lightning. He stuck MOV's all over
>the place, but I'm sure there's better stuff by now.
>--
>
>Terry Bowman, KA4HJH
>"The Mac Doctor"
>
>
>
>
>Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/

At 4:26 AM +0000 12/12/01, sucrosemusic wrote:
>
>Also, clipping the blue, cap-like thing out of my strip is ok,
>right?  Arrgh!  Again, I hate to spam, but I don't think I'm the only
>one here to wonder about this.  Anyone else come to the same
>conclusion here?

I'm still waiting to see the math.

>And more on-topic, exactly what is "star ground?"  I don't quite get
>why you'd need to run two ground lines to each module.  'splain?  I'm
>not 100% inept, so some techno-jargon is ok, but don't go too
>far.  ::grin::

You might like to go to www.analog.com and download application note AN-280
"Mixed Signal Circuit Techniques".  It explains many of the low noise
design techniques used in MOTM such as EMI prevention using ferrite beads,
proper shielding, PCB ground planes, etc.  It also includes a discussion on
star grounding, and will give you a better appreciation of your MOTM system.