Re: [TCML] Consensus on HV cable

[David Sharpe <sparktron01@xxxxxxxxx>]

---------------------------------------------------
Your power feeder could handle significantly more
yhen 400kVAR of load at 14.4kV and much more at say...
--------------------------------------------------

Sorry slipped slide rule, meant 40kVA.  Stand corrected!

Regards
DS

>
> RG8 from a conductor ampacity perspective is fine.  I've used as
> small as #18 at 5kVA input without issues.  I would recommend
> the use of SOLID PE dielectric RG8 however; the foam
> polyethylene with air inclusions has a much lower ultimate
> dielectric strength then the solid PE.
>
> Of course, if you really wanted to impress someone, use EDPM
> 15kV jumper power conductors (#6 is smallest size commercially available
> however).  X-Ray cable as previously mentioned is a suitable
> bragging rights alternative   ;^D
>
> Regards
>
> On Tue, Sep 14, 2010 at 1:51 PM, Joe Mastroianni <joe@xxxxxxxxxxxxxx> wrote:
>>
>> Not to pile on here, but just to do some of the calculations for the
>> original question:
>>
>>  - For a Pole Pig of 14400V output, and 1.0uf tank cap, 60Hz  Ichg=
>> 377*1x10^-6*14400 = 5.43A
>>
>>  - NEC Table 310-16 suggests ampacity for 10Ga AWG between 30 -40A depending
>> on temp, 60-90 C.
>>
>> - Inner conductor diameter of RG8/U coax is, depending on type, is between
>> 0.103" to  0.108" copper, stranded or solid, with insulating material of
>> foam polyethylene or teflon.
>>
>> - Diameter of solid 10Ga AWG copper is 0.102"
>>
>> - Therefore, using the center conductor only of a length of RG8/U is
>> feasible for a 1uf Tank primary + 14400V pole pig , taking only current into
>> account.
>>
>> Am I missing something in that brief analysis?
>>
>> However, I wonder if the group could comment - does it matter if the core
>> insulating material is foam-polyethylene,  or teflon?  Should one consider
>> shorting the shield to the center conductor to avoid creating some sort of
>> distributed capacitive transmission line (though at 60hz, probably not so
>> much of an issue)?
>>
>> Has anyone actually done this?
>>
>> Thanks in advance,
>>
>> Joe
>>
>>
>>
>>
>> On 9/14/2010 5:46 AM, David Sharpe wrote:
>>>
>>> David
>>>
>>> What is output voltage of pole pig?
>>> What is size of tank capacitor?
>>>
>>> Ichg ~ w * C * E  (w= 2*pi*f; 377);  C farads, E volts, Ichg amps
>>> Ichg is approximate steady state VAR current
>>>
>>>  Would size wire to support minimum 2X that value
>>>  (see NEC table 310-16 for typical conductor
>>>   ampacities).
>>>
>>> Typical #16 is good for 7.5A continuous which at
>>> 12kV is nearly 90kVA delivery to load; insulation
>>> to support applied voltage.
>>>
>>> Regards
>>>
>>> On Mon, Sep 13, 2010 at 11:49 PM, David Speck<Dave@xxxxxxxxxxxxxxxx>
>>>  wrote:
>>>>
>>>>  Esteemed list:
>>>>
>>>> Is there any consensus on the optimum gauge and insulation of the cable
>>>> that
>>>> goes from the HV output terminals of a 10 KVA pole pig to the RSG and
>>>> tank
>>>> cap of a 12" x 48" Coil?
>>>>
>>>> I seem to recall that the inner conductor of RG-8 coax with solid
>>>> polyethylene jacket and without the shield was the preferred material.
>>>>
>>>> Anyone found anything better?
>>>>
>>>> Thanks,
>>>> Dave
>>>> _______________________________________________
>>>> Tesla mailing list
>>>> Tesla@xxxxxxxxxx
>>>> http://www.pupman.com/mailman/listinfo/tesla
>>>>
>>>
>>>
>>
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>>
>
>
>
> --
> Dave Sharpe, TCBOR/HEAS
> Chesterfield, VA USA
>
> Sharpe's Axiom of Murphy's Law
> "Physics trumps opinion!"
>



-- 
Dave Sharpe, TCBOR/HEAS
Chesterfield, VA USA

Sharpe's Axiom of Murphy's Law
"Physics trumps opinion!"
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