Re: TESLA MAP UPDATED, and toroid measurements and availability

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <FutureT-at-aol-dot-com>

In a message dated 7/7/01 3:35:57 PM Eastern Daylight Time, tesla-at-pupman-dot-com 
writes:

> > In general,
>  > toroid sizes will fit a square law similar to the power input vs spark
>  > length equation, but using a different factor of course.  If the input
>  > power is quadrupled, the toroid size should be doubled.  I use a 4" x
>  > 13" toroid on my 600 watt coil, so a 2400 watt coil should use an
>  > 8" x 26" toroid from this point of view at 120 bps.  This is just a
>  > rough guide of course.
>  
>  Ok, I understand that, but I'm curious how one determines ROC with a power
>  law. Are
>  the above watts input watts measured? I would assume the 600 watts was a 
> meter measurement of input power.

Bart, all,

Comments interspersed, and comments on toroid measurements at
the bottom.  BTW, I have some small 1.75" x 6" toroids available for 
sale now.  See a previous email for details.

Yes, I generally use input watts measured, for my equations.  I avoid
using VA as much as possible especially for NST systems because
some folks use PFC and some don't.
>  
>  > I just did some quick calcs, and the Tesla Map results you
>  > cite do indeed fit the quidelines above for 120 bps, and result
>  > in a 17" by 60" toroid or so, and a larger overall diameter toroid
>  > could probably be used.   The toroid should be smaller for
>  > higher bps systems.  Richard Hull used a 13" or 15" by 60"
>  > toroid on his 10kVA Nemesis TC, which ran at about 500 bps,
>  > and was probably an actual 320 bps or so, considering missed
>  > firings of the async rotary.
>  
>  As you know there are losses that are obviously going to reduce the toroid 
> size
>  besides breakrate. 

The sizes I mention already take into account various losses because
they are empirically derived, then scaled up.

> Actual input power would better determine this, but it's 
> the
>  cart before the horse with transformer data. I'm guilty myself of using
>  transformer
>  data for your sparklength equation. How long the actual sparklength is 
helps
>  determine efficiency of power to the spark. It's one thing to run less than
>  efficient with a sparklength formula, but quite another should a coiler 
> build a
>  toroid and...... well, you know.
>  
>  > I have no idea if Tesla Map uses the chord concept or simply the
>  > overall size for the toroid sizes (I didn't look at the program).
>  > I always use the overall sizes, never the chord concepts.  When
>  > I speak of a 60" toroid, I mean 60" overall major diameter.
>  
>  Glad you identified this. TeslaMap is not using the major overall diameter.
>  This
>  may reduce the toroid major diameter in the program (assuming the program
>  did not
>  make this adjustment prior to evaluating the optimum toroid size - but,
>  maybe it
>  was adjusted).

I'd like to make a proposal to the list that everyone use overall sizes
for toroid measurement discussions on this list.  This approach 
seems much simpler  and more convenient than figuring out
various chord measurements.  As it is, about 99% of folks use 
the overall measurement approach.

For those who are not familiar with the chord concepts, it involves
placing a ruler across the top of the toroid and measuring the
distance between the two "high points".  As an example, a toroid
that is 6" x 24" overall, would measure 6" x 18" using the chord
concept.  I see only confusion and no benefits at all using these
chord concepts.  Companies that sell toroids such as OWL, and
Ross Eng, do not use the chord concepts, but simply state the
overall dimensions.  The dimensions for my small toroids are also
overall dimensions.

John Freau
-- 
>  
>  Take care,
>  Bart