[TCML] Consensus on HV cable
drieben at comcast.net
Tue Sep 14 10:59:50 MDT 2010
Yeah, what the "other" David "Sharpe" said. ;^|) I have found
that the high voltage cable that's used to transmit the high voltage
DC from the high voltage transformer/rectifier tank to the x-ray
tube head of an x-ray system works quite well for this purpose.
X-ray cable is basicallly desgined like coax cable on steroids, with
the exception that the inner conductor is usually two or three sepe-
rate low voltage isolated wires for the filament voltage on the cathode
side of the x-ray tube. I simply strip the thin insulation from these three
conductors and solder them all together. I then strip back the outer
plastic or rubber outer sheathing sleeve as well as the braided outer
condcutor and the semicondutor tape, all of them about 6" or so
back from the soldered end that is protruding from the heavy HV
If you're concerned about possible resonant or Bluemline voltage
rise along a considerable length of a coaxial like conductor set,
you can always completely strip off the entire outer sheathing,
conductor braid and semiconductor tape to leave just the inner
heavy HV insulated cables. Keep in mind that these x-ray cables
are typically desinged for 75 kVDC, and although their maximum
safe AC voltage standoff would be considerably less, they are
still able to handily hold off the mainly sub-20 kV(AC) voltages
that are encountered from a pole transformer.
The "third" David "Rieben"
> 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
> Typical #16 is good for 7.5A continuous which at
> 12kV is nearly 90kVA delivery to load; insulation
> to support applied voltage.
----- Original Message -----
From: "David Speck" <Dave at davidspeckmd.org>
To: "Tesla Coil Mailing List" <tesla at pupman.com>
Sent: Monday, September 13, 2010 10:49 PM
Subject: [TCML] Consensus on HV cable
> 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?
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