Re: How to make a cheap and effective inductive ballast

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Harvey Norris <harvich@xxxxxxxxx>



--- Tesla list <tesla@xxxxxxxxxx> wrote:

> Original poster: "miles waldron"
> <mileswaldron@xxxxxxxxxxx>
>
> Get two spools of 400 feet of #14 wire from Lowe's .
> Zip tie each spool into
> a nice tight 8" coil. Submerge the coils in cold
> water with the winds facing
> each other. Turn on the ballast circuit and see if
> the coils are drawn
> together or pushed apart.
This surprises me greatly that magnetic forces between
these coils could manifest themselves without an iron
core? I have used hardware store bought 14 gauge, 500
ft coils;(~11mh @ ~1.2 ohms) in 480 hz connections to
garage motor driven AC car alternator, and found the
mutual inductance to be a small value. If however the
coils were given C values in series for resonance, a
DIFFERENT coefficient of mutual coupling manifests
itself. Two adjacent rows of ten spools each in series
used as LC(primary) in one row and LC(secondary) as a
measured shorted loop on the second adjacent row shows
that 1/4 of the currents found in the primary circuit
are induced in the secondary loop. However the
preliminary reactive current measurements of these two
adjacent rows in order to determine the balancing C
value to be used for series resonance shows that
practically no mutual inductance exists between the
columns themselves. This then is the reason for
stating that different co-efficients of coupling
appear to be evident for both the reactive and
resonant cases. To get an idea of the mutual
inductance of the spools placed base to base in series
we find that ten of the 11 mh coils in series is not
110 mh but instead increased about 1/3 to 150 mh.

 In one particular
> measurement, when the coils were
> arranged so that they pushed apart, the overall
> circuit passed 67 amps, and
> when the coils were attracted together, the same
> circuit passed only 42
> amps.
These values seem a bit high for 14 gauge wire? Are
the coils placed in parallel in the ballasting?

The pushed apart coils submerged in water
> inductive ballast only costs
> about $40 to make, and is a great ballast, and heats
> shower or bathing water
> very quickly.
No doubt, I would hate to see what would happen if the
water was not present as a heat transfer agent! HDN
> Ideas, comments, suggestions, and verifications very
> much appreciated.
>
>
>