SV: Re: SV: Re: [sdiy] midi optocouplers

[Magnus Danielson]

From: Seb Francis <seb at burnit.co.uk>
Subject: Re: SV: Re: SV: Re: [sdiy] midi optocouplers
Date: Mon, 12 Dec 2005 22:18:51 +0000
Message-ID: <439DF74B.4000807 at burnit.co.uk>

> Well I don't know about the US, but in UK where we also have 3-wire 
> polarized mains this is not true.  I don't think neutral is tied to 
> earth ground.  'Neutral' refers to the common connection of a 3-phase 
> generator output.  In a domestic house only 1 of the phases is delivered 
> and the neutral connection is the current return path.  If you connect a 
> neutral wire to an earth wire then I would imagine you will blow the 
> fuse.  But maybe this is different in US?
> 
> Some more reading ..
> http://en.wikipedia.org/wiki/Alternating_current
> http://en.wikipedia.org/wiki/Neutral_point

Even with 
http://en.wikipedia.org/wiki/Split_phase

There are several mistakes which doesn't make it necessarilly work outside UK.

For instance, here in Sweden we have 400 VAC three-phase system. You get 400V
in delta-connection but is mostly used as three 230 VAC phases in Y-connection
and the zero is hooked to ground in the local step-down transformer.

So, don't beleive that Wikipedia is the absolute reference. Review it
critically! These things changes by country, so we could talk around the
subject for a long time before we learn what local variants we are really
starting from. For instance, in Sweden is the standard Chuko-connector not
polarized, where it is in Germany for instance. It took some time for me and
Jürgen to sort that detail out for instance.

Electrical standards are nice, every country has at least one set, and a whole
number of old incompatible ones. Some small parts of the US I still beleive run at 24 Hz for instance... imagine that!

Cheers,
Magnus

> Seb
> 
> P.S. Hopefully someone with some firm knowledge of UK mains power will 
> correct me if I'm wrong ...
> 
> 
> harrybissell wrote:
> 
> >USA uses 120VAC...
> >
> >Hot will have 120V AC with respect to earth ground
> >
> >Neutral should have no voltage with respect to earth ground.
> >
> >They can get reversed sometimes... with disasterous results in
> >an audio system.  Having one chassis at 'hot' and another at
> >neutral can mean line voltage in an audio cable...
> >
> >H^) harry
> >
> >Karl Ekdahl wrote:
> >
> >  
> >
> >>I'd really like to know what the "hot"/"neutral" is all about, here in
> >>sweden we've got no such thing but i'm moving to the US in a week so
> >>i'd better learn....
> >>
> >>Karl
> >>
> >>Samppa Tolvanen <samppa.tolvanen at gmail.com> skrev:
> >>
> >>      We Finns are enjoying 230VAC with non-polarized mains
> >>     sockets.
> >>
> >>     Shouldn't We all agree the truth, there's NO neutral wire.
> >>     Just for newbies?
> >>
> >>     Grant said:
> >>     "It is a good idea to verify that your electronic music
> >>     studio wall
> >>     sockets are wired correctly.
> >>     I have seen strange things happen when neutral and hot are
> >>     reversed.
> >>     Even on transformer isolated equipment."
> >>
> >>     This sounds like badly designed equipment.
> >>
> >>     Samppa
> >>
> >>
> >>    
> >>
> >
> >
> >
> >  
> >