Re: Remote Power Supply Connection

On Tue, 20 May 2008 07:00:30 +1000, "Trevor Wilson"
<trevor@[EMAIL PROTECTED]
> wrote:

>
>
>"flipper" <flipper@[EMAIL PROTECTED]
> wrote in message 
>news:tbt23457an3suhr0kjfv2lhuiq0v0o4jjd@[EMAIL PROTECTED]
>> On Sun, 18 May 2008 12:09:45 +1000, "Trevor Wilson"
>> <trevor@[EMAIL PROTECTED]
> wrote:
>>
>>>
>>>"flipper" <flipper@[EMAIL PROTECTED]
> wrote in message
>>>news:2e1v24tp96nb7n7dopacuig5rv7hubtiru@[EMAIL PROTECTED]
>>>> On Sun, 18 May 2008 09:04:49 +1000, "Trevor Wilson"
>>>> <trevor@[EMAIL PROTECTED]
> wrote:
>>>>
>>>>>
>>>>>"flipper" <flipper@[EMAIL PROTECTED]
> wrote in message
>>>>>news:oolu249l2p19arj95g2it4fhjag238ajfl@[EMAIL PROTECTED]
>>>>>> On Sun, 18 May 2008 07:36:56 +1000, "Trevor Wilson"
>>>>>> <trevor@[EMAIL PROTECTED]
> wrote:
>>>>>>
>>>>>>>
>>>>>>>"Ian Thompson-Bell" <ruffrecords@[EMAIL PROTECTED]
> wrote in message
>>>>>>>news:g0mu6g$2vgp$1@[EMAIL PROTECTED]
>>>>>>>> Trevor Wilson wrote:
>>>>>>>>> **Asked and answered. Use AC. Do not use DC.
>>>>>>>>>
>>>>>>>>
>>>>>>>> In practice that is perhaps not such a good idea as it sounds. It
>>>>>>>> means
>>>>>>>> the rectifiers will be at the end of a fairly long piece of
cable. 
>>>>>>>> The
>>>>>>>> large rate of changes of current caused by rectifiers (especially

>>>>>>>> the
>>>>>>>> semiconductor type) combined with the series inductance of the
cable
>>>>>>>> is
>>>>>>>> a
>>>>>>>> recipe for noise, interference and possibly stability problems.
>>>>>>>
>>>>>>>**I fail to see how. In practice rectifiers are already at the end
of
>>>>>>>very
>>>>>>>long cables and are supplied by devices with prodigious inductance.
In
>>>>>>>any
>>>>>>>case, there are measures that can be taken to reduce the problems
>>>>>>>associated
>>>>>>>with noise from diodes. There are even (easy) measures which can be
>>>>>>>taken
>>>>>>>to
>>>>>>>reduce the inductance of those connecting cables. What I am very
>>>>>>>concerned
>>>>>>>about is the extreme ignorance displayed about the dangers
associated
>>>>>>>with
>>>>>>>DC arcs and connectors. This, as opposed to your hypothetical, is a

>>>>>>>very
>>>>>>>real possibility. Read this:
>>>>>>>
>>>>>>>http://www.arcadvisor.com/faq/dc_direct_current_arc.html
>>>>>>>
>>>>>>>Trevor Wilson
>>>>>>>
>>>>>>
>>>>>> The connector isn't a switch, relay, or fuse.
>>>>>
>>>>>**Indeed. If it is unplugged, whilst 'hot' a disaster could result.
>>>>
>>>> While I'm not particularly enamored with the idea of HVDC umbilicals
>>>> it doesn't take too much thought to come up with at least one means
to
>>>> prevent manual disconnect while hot and I'm sure a few minutes more
>>>> could produce others.
>>>
>>>**I've not seen any solutions proferred yet.
>>
>> You didn't ask for one.
>
>**Exactly.

Then complaining you weren't offered one is 'dumb'.

> Using AC dispenses with the need to go to heroic and expensive 
>lengths to solve a non-existent problem.

As already mentioned, you sure as hell wouldn't know because one has
to at least contemplate the possibility to have a clue, and you
obviously haven't.


>>> However, the use of AC
>>>eliminates any problems. There is no downside.
>>
>> You sure as hell wouldn't know because one has to at least contemplate
>> the possibility to have a clue, and you obviously haven't.
>
>**I've presented the problems with DC.

You've present what you perceive as one problem and it's the only
thing you've given so much as 1 mS of thought to.

> It seems I am the ONLY one 
>contemplating the the possibility.

An obviously false statement.

>>>>> Using AC
>>>>>eliminates any possibility of such a disaster.
>>>>
>>>> So does preventing disconnect while hot and you seem to have
>>>> completely missed the entire discussion about how to ensure 'no
touchy
>>>> hot pins'. And, if done right,  no 'touchy hot' could also mean no
>>>> 'arcy disaster hot'.
>>>
>>>**Then present your solution and explain why is is better than using
AC.
>>
>> So you admit being unable to come up with even one and need me to
>> solve it for you?
>
>**I already provided a solution - use AC.

That isn't the problem you asked a solution to.


>>>>> Using DC is just dumb.
>>>>
>>>> You really should look for a more congenial means to salve your ego.
>>>
>>>**Just dealing in the facts. Inconvenient that they are. Using AC is
much
>>>smarter, safer and simpler. Using DC is dumb, unsafe and inconveniently
>>>complex.
>>
>> No, you deal in 'opinion' and self aggrandizing insults;
>
>**Nope. I have not insulted anyone.

Just called anyone who uses DC "dumb." And claming that isn't an
insult is 'dumb'.

> OTOH, I have been insulted for providing 
>logical, consistent suggestions.

No, you've been criticized for being an ass.

> I wonder why that is?

Because you behave like an ass.


> made
>> abundantly clear by the fact that what you witlessly call 'dumb' has,
>> in one form or the other, been common practice for 75 years, or more.
>
>**That it has been used, does not mean it is not a foolish idea.

Once or twice, no. 75 years, yes.