Re: Remote Power Supply Connection

"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. However, the use of AC 
eliminates any problems. There is no downside.

>
>> 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.

>
>> 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.

Trevor Wilson