@Lawrence & @all
(I had to give up the long waiting to get the attached file approved,
so I put it on an external service instead)
I first found Lawrence work on the FLEET-device on the OUR-forum,
but it was blocked for other than internally admired members
So I first sent this mail a couple of weeks ago to the hotmail and
netvigator.com address of Lawrence, but it possibly didn't work.
--------------------------------------------
>
> --- On Fri, 1/11/13, be_design2004
> wrote:
>
> > Subject: Optimizing the efficiency of the FLEET demo
> > To: "Ltseung@hotmail.com"
> <Ltseung@hotmail.com>
> > Date: Friday, January 11, 2013, 1:48 PM
> > Hi Lawrence,
> >
> > hotmail has been unreliable many days lately,
> > so i hope this gets through.
> > (zoho.com may be an ad-free alternative)
> >
> > The OUR-forum was blocked for other than internally
> > admired members
so I send this mail instead -
> >
> > --------------------------
> > (just in case you would refer to my mail
> > publicly, pls first delete my address and
> > this sentence)
> > --------------------------
> >
> > If you possibly already are aware of the suggested
> details below, just disregard them
> >
> >
> > From reading your experience of varying results with
> > different loads, and as you have some serious instrument
resources, I'll suggest it's a good opportunity to compare
the effect of load matching with your baseline measurements.
> >
> >
> > 1.
> > Here is an xls-tool - Most_effficient_load_impedance.xls:
http://db.tt/vBhbjou6 which should quickly
> > point to the ideal load for the circuit,
> > if the load is mostly resistive.
> >
> >
> > Just plug the three *readings from your setups into
the tool -
> >
> > Like from your example:
> > (Your data below indicates your load is close to 25 Ohm)
>
> >
http://www.overunityresearch.com/index.php?PHPSESSID=2fa991b1d3da74133797f92f553899a6&action=dlattach;topic=1617.0;attach=9094;image> >
> > ---------------------------------
> > Example: *
> > 'Unloaded' use say a 10K load for more safety while measuring
output voltage = ?
> > (dummy or present)Load resistance = 25
> > Voltage(rms) over the connected load = 2.48
> > ---------------------------------
> >
> > Then replace the load with one having the resulting
> > equvivalent value, and compare making new measurements.
> >
> > Perhaps it's best to take the 'unloaded'
> > voltage reading with a load of more than 100 times
> > higher resistance than the real estimated load,
> > as a totally unload inductive 'spiky' source cold
give misleading readings and also risk damaging
> > the instruments - a resistive divider will be
> > even more secure while measuring.
> > (the resulting error will be totally
> > insignificant)
> >
> >
> > 2.
> > As we are generating milliwatts, every circuit part
> > matters for improving the result - also on the
> > drive side.
> >
> > The base resistor power loss increases with the square
> of the voltage over it, so it should be matched with the
> > driving winding turns number.
> >
> > Perhaps one could try with some less drive winding
> turns balanced with lower base resistor values.
> > (if not the symmetrical transformer is an essential
> part of the concept)?
> >
> >
> > 3.
> > Something more to try -
> > If you remember, 50 years ago the best method to speed
> up a silicon transistor was to connect a germanium diode
> with it's conducting direction from the base to the
> collector.
> > A modern schottky type could be tried too.
> > (BTW - the 2N2222 is more than 50 years old)
> >
> > 4.
> >
> > The base resistor, after the eventual matching as
> above, could have a small value capacitor in parallel
to help speed the switching to compensate/balance
for a lower average drive current to further save
energy.
> >
> > 5.
> > The core needs to handle the maximum flux at the
> highest supply voltage, otherwise it will saturate
into lower efficiency, this could explain the observed
increased COP at lower drive voltage.
> >
> > The noted correlation with higher frequency also
> > results in less average flux in the core as the
> > impedance increases with frequency.
> >
> >
> > 6.
> > The conclusion of this points to the use of a more stabilized
> > operating source voltage for a practical user device.
> >
> >
> > would be interesting to see if any of this
could be of use as I currently have no lab
setup available
> >
> > Best whises for the comming New Year
>
> > /be_design2004
----------------------------
Lawrence, did you receive this on your hotmail address?
