Re: [TCML] Burn Through The Stem Of The Globe?

[DC Cox <resonance@xxxxxxxxxxxx>]

inductive reactance, capacitive reactance, and also resonance must also be
considered.  For example, if the resonant match impedance of
the globe is of a certain value, then currents can increase beyond the
typical 1 mA safety value for most globe designs.

Dr. Resonance





On Sun, Jan 18, 2009 at 11:01 AM, Scott Bogard <sdbogard@xxxxxxxxx> wrote:

> Miles,
>     I'm assuming Ohms law to be correct (V=IR, higher V constant R,
> higher I), and I'm assuming impedance to be constant, and I'm
> justifying these assumptions based on being told the fuse for the
> driver was a 10 Amp fuse (not one or two amps.)  However like I said,
> this is hearsay, based on pictures and description over the phone, I
> have not personally seen the fuse, and the person on the other end of
> the line may have misread the number.  There may be more to it than
> that!  I love the elegance and simplicity of the ZVS driver, and one
> cannot compete with the power outputs, however I want to design a
> circuit of my own from the ground up, and I want infinite run times,
> so I'm afraid the ZVS driver is not for me right now.
>
> Scott Bogard.
>
> On 1/18/09, miles waldron <mileswaldron@xxxxxxxxxxx> wrote:
> >
> > Scott,
> >
> > Wait! Math wierdness. 2 amps at 12V, would be 0.2 amps at 120V. You are
> more
> > likely in the 20 watt range. The IRFP450 ZVS is an absolute champ driver
> > circuit, and I can get to almost 120 watts with it. Nothing else that I
> > tried comes even close to driving a flyback as well.
> >
> > Another thing to remember Miles, is that the globes Mark used were old,
> and
> > they just don't make stuff like they used too; it is highly probable that
> > the glass is substantially thicker on Marks globes.  I have heard of many
> > MOSFET driven globes dying, especially when driven by the power supplies
> for
> > sale at Amazing1, but then again from what I know of those drivers they
> run
> > off of Rectified 120V, but I don't know that for sure from looking at
> > pictures (I suspect this because I saw no step down transformer in the
> > works, and the thing had an AC wall
> > plug.)  If my globe draws 2 amps at 12 V, that could mean 20 A at 120V,
> or
> > 2400W at full power (which is an absurd value, so I'm sure there are
> means
> > to prevent this.)  Just my two cents, I'm no expert.
> >
> > Scott Bogard.
> >
> >
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