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Re: [TCML] HV wire ?
I misspoke, 3M Scotch tape we use is 130C, self vulcanizing EPR
linerless tape for
stress cones/insulation up to 69kV.
http://www.alliedelec.com/Images/Products/DataSheets/BM/3M_ELECTRONIC_SPECIALTY_MKTS/3MElectronic-Specialty-Mkts_Production-Supplies_6170130.pdf
Our company goes through at least a case a month, and swears by it.
Is expensive
though at ~ $20 a roll; in your application you might want to consider
small stress
cones at termination ends of these cables at your termination lugs.
Don't forget to
radius all sharp corners on your terminations/lugs to reduce risk of
corona/tracking.
Regards
On Wed, Jun 16, 2010 at 12:11 AM, Ian Charnas <ian.charnas@xxxxxxxxx> wrote:
> Thanks everyone for the tips and questions. It was difficult to find
> what we needed in small quantities, most companies want to sell 100'
> or 500' spools for kilobucks. We ended up getting a donation of 20'
> of 25kv 1/0 from a local electric supply company, however our backup
> plan was this wire here:
> http://www.tpcwire.com/tpc2.aspx?Id=MediumVoltage_MobileSubStation_TypeSHCables
>
> We found a lot of wire meant for burial that was suitable, but not
> flexible enough for our application. The cable meant for a "mobile
> substation" has thinner strands and non-pvc casings so they're less
> stiff than the stuff meant for burial.
>
> We're trying to make a professional go at this coil, we've got CNC'd
> bus sheets, high-flow water-cooled custom heatsinks for the h-bridge,
> shock-mount 19" travel racks for all our power electronics, and so
> forth. For a less demanding coil we would have gone with the sleeved
> option, or just no HV shielding and try to position things so it's not
> a problem. For this coil we want to arrive at a venue and be set up
> to do a musical tesla coil show within 1 hour, so we need a guaranteed
> no-problem solution, hence the HV wire.
>
> In terms of gauge, we wanted 1/0 because we are handling lots of
> current and want low resistance.
>
> many thanks again for the comments, hope this thread will be helpful
> to future googler's.
> Ian
>
> On Tue, Jun 15, 2010 at 4:49 PM, David Sharpe <sparktron01@xxxxxxxxx> wrote:
>> Allied Wire and Cable stocks 7.5kV EDPM non-shielded cable from #8 up
>>
>> http://www.awcwire.com/ProductSpec.aspx?id=EPDM-7500V
>>
>> It is also available in 15kV from Industrial Electric Wire and Cable.
>>
>> http://www.iewc.com/CatalogProduct.aspx?product_id=53
>>
>> Note 5/15kV EPR 210 Jumper Cable
>>
>> Our company is rebuilding on old GE Magnablast 5kV (2.3kV actual)
>> contactor with Joslyn Vacuum contactor and these conductors as used
>> as "whips" to terminate to isolation switches and 2.3kV horizontal
>> busbars in MCC lineup. Tape ends with Scotch 160 for stress cones
>> and job is done. FWIW using 4/0 conductors on contactor where motor
>> has a connected load (measured) of 20A (100-125HP induction motor).
>> Massive overkill, but you don't mess around with 2.3kV MCC fed by a
>> 2500kVA transformer either...
>>
>> Regards
>>
>> On Tue, Jun 15, 2010 at 12:54 PM, Michael Twieg <mdt24@xxxxxxxx> wrote:
>>> We might peak at 2000amps, and if we burst at a high repitition rate the rms
>>> primary current could feasibly get that up to 500A. We definitely couldn't
>>> run that high for extended periods of time, though. And no, we're not
>>> looking at 10MW or something ridiculous. The load is mainly reactive, not
>>> resistive, so we're only looking at real power delivery of maybe 30KW
>>> average.
>>>
>>> And the wire has to be somewhat flexible, so tubing isn't an option. It
>>> will probably need to be between 1 and 2 meters long. IMO this isn't
>>> incredibly critical, but we wanted a pro solution if possible.
>>>
>>> -Mike
>>>
>>> On Tue, Jun 15, 2010 at 9:24 AM, jimlux <jimlux@xxxxxxxxxxxxx> wrote:
>>>
>>>> Michael Twieg wrote:
>>>>
>>>>> This is for out DRSSTC, the cable going between the primary coil and
>>>>> primary
>>>>> capacitor. The primary will see maybe up to 500 amps RMS, and the voltage
>>>>> at that note may be up to 15KV peak. We were advised by a professional
>>>>> power electronics engineer to not simply throw rubber insulator on a
>>>>> cable.
>>>>> Apparently air between the conductor and insulator will ionize, which will
>>>>> chemically degrade the insulation over time. We were just looking for a
>>>>> more robust solution.
>>>>>
>>>>>
>>>> They're right about the insulation degradation.
>>>>
>>>> But, as others have posted, why insulate at all?
>>>>
>>>> 500A RMS? at 15kV that's almost 10 Megawatts.
>>>>
>>>> Perhaps you mean you've got pulses, during the pulse you've got 500A RMS?
>>>>
>>>> Anyway, you're looking for tubing here, both for the low inductance, and
>>>> because at the frequency, skin effect means that you're only using the
>>>> outside layer of the wire, so why spend the money on copper you aren't
>>>> using. Use 1/2" copper tubing or something similar. You could also
>>>> probably use the shield of coax cable. you can connect the center conductor
>>>> in parallel.
>>>>
>>>> In any case, trying to find insulated wire rated for the insulation is
>>>> going to be a chore.
>>>>
>>>> Also, just how long a run is this? And does it really make much
>>>> difference? If you went from AWG0 to AWG 20, it's going to be roughly a
>>>> factor of 10 in AC resistance. If the run is, say, 2 feet long, that's a
>>>> few milliohms difference. At 500Arms that's about 250W/milliohm, but I
>>>> suspect that's pulsed(e.g. you don't have a handy 10 MW wall socket to plug
>>>> into), and in any case, the average power dissipation will be quite low.
>>>>
>>>>
>>>> Or, more practically, if you want insulated wire, get some AWG14 HV wire
>>>> and try it. If it melts, THEN go get your insulated copper bar stock...
>>>>
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>>
>>
>>
>> --
>> Dave Sharpe, TCBOR/HEAS
>> Chesterfield, VA USA
>>
>> Sharpe's Axiom of Murphy's Law
>> "Physics trumps opinion!"
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>>
> _______________________________________________
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>
--
Dave Sharpe, TCBOR/HEAS
Chesterfield, VA USA
Sharpe's Axiom of Murphy's Law
"Physics trumps opinion!"
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