Joule Ringer!

[JouleSeeker]

   My Lux Meter arrived yesterday and I now have three different setups to test.  The LJL with multiple taps for CFL’s, the LJL with speaker wire for LED’s, and a third setup which I will describe.  Have not made the box yet to test the bulbs, 
The third setup can be seen below.  I found a transformer that I had salvaged from a speaker system some time back.  This was a Harman/kardon 10 year old system that went bad.  The transformer is a 120VAC 60Hz input with 18VAC 3A output.  This setup is very sensitive to get started, but when it does, it performs very well.  I placed a string of 50 LED’s rated at 4.8 watts, a LOA rated at 2 watts, and a FEIT Bathroom and Vanity rated at 1.2 watts on the circuit for a total of 8 watts load.  Running off a 12 Volt battery, the current draw was 240mA resulting in 2.88 watts. Using my new Lux Meter I tested the LOA on AC and the meter showed 660.  Running off the circuit the meter showed 1450.  Those numbers are approximations since the numbers were bouncing around a bit.  With these readings being totally unexpected, I performed the test a second time and the results confirmed the first test.

Brad S

Isn't it great to have actual NUMBERS MEASURED -- 1450 lux with the SJR and 600 lux with the grid...   Exciting-- however, I ask that you PLEASE PUT THE LUX METER AND THE BULB(S) IN A FIXED POSITION IN A FOIL-LINED "LIGHT BOX". 

In this way, you can be sure that the meter and bulb do not shift around when taking measurements.  Also, you can put in known bulbs, known Lumens output, and calibrate your light-box (as described earlier in this thread), getting Lumens/Lux conversion factor for your box.  THEN you can calculate Lumens (out)/ Watts (in).
Photo of my light box, as an example, is shown earlier in the thread.

[JouleSeeker]

   LynxSteam was kind to send me one of his air-coils for testing, with the Lasersaber 2.0 circuit; see photo.  Thanks, Lynxsteam!!!  Primary has 34 windings, secondary has 368 windings.    I used the light box for the tests, described earlier.

       Photo also shows the DSO waveform when a 13W CFL bulb was the load (left) -- approx sinusoidal.  The right waveforme is for a 3.5 W LED bulb -- almost a square wave.  So the load clearly changes the waveform; and also the frequency of the output signal, as shown in the table.

   Gotta run -- please study the table and ask questions as you wish.  Shows the versatility and ease-of-use of the light box.  Note that I'm only getting about 23 Lumens (out)/ Watt (in) max with this  -- not bad for an air core, IMO.  These LED lamps running on the grid-AC put out about 60 Lumens/Watt.      More runs coming!   

[conradelektro]

I got an E-Core transformer (FERROXCUBE ETD49/25/16-3C90 FERRITE CORE, Farnell order code 3056417) which oscillates at about 8 KHz with the circuit below. The little circuit modifications help to start the oscillations and keep the transistor cool.

The 8 KHz still seem to be too high because some lamps perform poorly, others perform really well. This depends I guess on the internal circuit of the lamp.

I have some CFLs (unmodified) which light up very bright with less power consumption as specified by the manufacture at 220V. Some other CFLs I have only light up when they consume more than specified.

Only my small LED lamps (0.8 Watt, 1 Watt and 2.5 Watt) perform very well but only at 6 Volt (12 Volt would blow them up), they are very bright at about 70% of their specified power consumption (of course my judgement by eyesight is inaccurate). But the two big LED lamps (5 Watt and 9 Watt) need more power than specified.

Also incandescent lamps light a little (red glow) and consume much less than specified (about 6 Watt) but give almost no light, they just become hot.

I attribute the high power consumption of some CFLs and some LED lamps to the still too high frequency of about 8 KHz (which does not agree with the internal circuit of some lamps). If you look at the table posted by LynxSteam, you also see that some lamps perform poorly probably because the frequency of his air core is 30 KHz to 100 KHz.

So, how can I bring down the frequency of my E-Core transformer? How do I have to modify the circuit? Capacitors, where?

The screeching is just awful, with all lamps at 12 Volt (only with the little LED lamps at 6 Volt I hear nothing).

Greetings, Conrad

[b_rads]

Professor - here goes!  I recorded some numbers and I hope you can make some sense of them.  First let me say that the transformer reguired the 4.8 watt LED string connected to get it to run.  It runs in the 240 to 280mA range for a while and then it jumped to 450mA.  I got my readings when it was at 450.  All readings used 12 Volt source.

1.2 watt FEIT rated at 74 Lumens.
AC Power - 1030 Lux
AirCore LJL - 580 mA - 1672 Lux
Torid Transformer - 450 mA - 2290 Lux

2.0 watt LOA rated at 110 Lumens
AC Power - 1370 Lux
AirCore LJL - 620 mA - 1595 Lux
Torid Transformer - 450 mA - 2090 Lux

Both Bulbs Together
AC Power - 2620 Lux
AirCore LJL - 640 mA - 1824 Lux
Torid Transformer - 480 mA - 2480 Lux

BTW - I now understand the importance of the light box, Thanks!
Brad S   

[Lynxsteam]

ConradElektro

It looks like you setup that E-Core exactly as Laser Saber specified, although his drawing shows 20:200 turns I think.  My latest has 16:160 turns.  I use just a tiny amount of adhesive between the E-Cores.  Its called "Shoe Goop" or just "Goop" brand.  It is flexible when set up, but very tough adhesive.  I think even double sided tape would work.  You just need something to cushion the chattering of the two cores together.

As for amp draw.  I am finding that more total turns (total of secondary and primary) lowers amp draw.  More turns equals more induction.  I am starting to wonder with my air-cores if turns ratio even matters.  I doubled the primary turns on my latest air-core and the bulbs still light nicely and the amp draw dropped by half.  So what happens if I double primary turns again?  We are not transforming AC/AC in a ratio.  This is a flyback transformer, so whatever AC voltage we generate the High Voltage spikes from flyback will ride on that waveform.

JouleSeeker's Lux/lumens findings vs watts input matches what I saw with the first prototype.  Now I am finding that I can drop the amps dramatically by increasing primary turns.

The other thing I find with the E-Cores and AirCores s that you wont see the full efficiency until you add more bulbs.  The air-core gets more and more impressive as you add bulbs.  One bulb takes 400 ma, 2 bulbs 500 ma.  Each added bulb only consumes 100 ma more.  The E-Core is a little different.  It will consume only about 400 ma and little more as you add more bulbs.  So a one bulb test doesn't tell the whole story on these devices.