Concrete materials can act as a shorted turn

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Original poster: "Dr.Resonance by way of Terry Fritz <teslalist-at-qwest-dot-net>" <resonance-at-jvlnet-dot-com>


Concrete itself can act as a good conductor of high voltage, high frequency
currents.  It is important in your design to keep the primary coil (the
upper section of the subbase assembly) high above the ground plane
represented by a concrete surface.

For small coils operating on table tops, usually 7-8 inches is adequate.
For medium size machines (2.5-4.0 kVA) at least 14-16 inches are
recommended.  For large coils systems usually 24-48 inches are required to
prevent primary induced current losses.

It is also very critical with any system to have a good external ground
system.  We prefer to use a minimum of 3 copper ground rods driven 12-15 ft.
apart and interconnected with no less than 2 AWG fine stranded copper
welding cable.  The input line is also 2 AWG copper welding cable.  The fine
strands do a better job of conducting HF currents.

Best regards,

Dr. Resonance




----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Sunday, January 19, 2003 4:39 PM
Subject: Shorted loops of concrete reinforcing effect res freq?


 > Original poster: "Christopher Rutherford by way of Terry Fritz
<teslalist-at-qwest-dot-net>" <Christopher.Rutherford-at-comindico-dot-com.au>
 >
 > Hello,
 > I recently move my coil outside of my garage to run it and have found its
 > working much better. I suspect that the loops in the steel reinforcing
 > under the concrete of may garage may have loaded it??
 > I don't think I should have to retune it now that its had these 'shorted
 > turns' removed, is this right?
 > Basically only the Q has gone up? ...is this thinking right?
 > Cheers & thanks
 > Chris
 >
 >