# How: (Re: magnetically quenched gaps)

```Original poster: "davep by way of Terry Fritz <twftesla-at-qwest-dot-net>" <davep-at-quik-dot-com>

> Original poster: "David Kyle by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<dave-at-kyleusa-dot-com>

> I am very intrigued by the concept of a magnetically quenched spark gap
> and I am curious on what basis they operate.

Consider that an arc (or spark) is a current carrying
conductor.
Consider that a current carrying conductor, in a
_crossways_ (transverse) magnetic field will
experience a force.
If free to move, the conductor will.
(basis of most electric motor design).
If both ends are anchored (as an arc to electrodes)
the middle will get longer.  (bow out).
If it gets longer it will get closer to 'going out'.

> Can anyone explain the principle as to how they aid the

>quenching of a static gap of an AC driven Tesla coil?

cf above.

> Has anyone successfully demonstrated a magnetically quenched

>gap

On what?
They are routinely used in HV AC and DC design, eg on
power systems.  They were, IIR, used in 'wireless'
gaps of old.  I think Tesla used them.

> with a measurable difference with and without the magnetic

>field?

cf above.  They work.  Whether they work for Tesla
systems, and whether they work better than
alternatives...

> Can the magnetic field be stationary using permanent magnets?

Yes.  (many industrial applications use AC excitation,
more, i think, for convenience, ie the load current
provides the extinction current).

> What is the most effective geometry to place the magnets?

Field lines to be transverse (crossways) to the line
between the electrodes.

> How strong must the field be?

Stronger the better.  (not a real useful answer...)

> Would there be benefit in using a powerful electromagnet

>operating in sync with the primary supply?

This is a routine way of doing blow out in contactors,
overload devices, etc.  Need not be 'in sync'
if the load current itself is used.  (But.  Such
applications are a bit different: there is normally 'no
gap', with blowout required whenever the gap opens.
Tesla gap applications are a bit different, with
current flow desired/required at times.  One might
do better with a DC (or permanent magnet) field.
Further, usual standard applications involve an opening
gap (electrodes moving, arc stretching).  Application
to a static gap may be less effective.

best
dwp

```