RE: [TCML] can you connect the secondary *directly* to the primary?

["Lau, Gary" <Gary.Lau@xxxxxx>]

Connecting the secondary base to the primary is bad for several reasons.  It should work just fine, but...

Safety-wise, this places high-current primary-side voltage on the secondary, making touching any part of the secondary, topload, or secondary discharge lethal.

Realize too that whatever RF current comes off the topload into sparks, the return current must travel through the secondary base.  If the base is connected directly to (RF) ground, everyone is happy.  But if instead it connects to the primary, that return current will probably flow to the NST and mains power lines (BAD!) in searching for a path to ground.

There really is no functional advantage to connecting the secondary base to the primary.  But if the inside primary lead can be grounded, there may be insulation advantages to connecting the secondary base directly to it.

Regards, Gary Lau
MA, USA


> From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On
> Behalf Of Tim Meehan
> Sent: Thursday, November 15, 2007 12:07 AM
> To: Tesla Coil Mailing List
> Subject: [TCML] can you connect the secondary *directly* to the primary?
>
> I sort of already know the answer to the question, but since I am pretty new
> to the tesla coil hobby I figured that I'd ask to learn about everything
> that was wrong with my idea.
>
> When I first saw the circuit for the tesla coil primary and secondary - I
> thought that it bore some similarities to an autotransformer or an
> automotive ignition coil.  So I figured that I might get it to work if I
> connected the base of the secondary to one side of the primary circuit.
> (This might not suprise you, but it didn't work - no matter how much I
> wanted it to.)
>
> I started to look at the schematics on many websites and noticed that all of
> the secondaries were connected to an earth ground.  I wasn't near my coil to
> try to move the connection to an earth ground, but that will be the first
> thing that I try ... but will it not work as an autotransformer because the
> coupling is too weak?

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