Claimed OU circuit of Rosemary Ainslie

[poynt99]

Luc,

If you're looking for a 0.25 Ohm resistor, I used this:

http://search.digikey.com/scripts/DkSearch/dksus.dll?lang=en&site=US&WT.z_homepage_link=hp_go_button&KeyWords=15fr250e&x=0&y=0

P/N: 15FR250E. It is a 1%, 5W.

Inductance measures to 1uH.

.99

[Hoppy]

Glen:

I don't agree with your comments on .99's setup.  It looks pretty good to me overall.  The one point that you make that I think has some merit is about the load resistor being directly over the circuit.  However, the magnetic field generated by the load resistor is synchronous with the operation of the circuit.  In that sense it is not like an unrelated magnetic filed that would induce an asynchronous disturbance into the circuit.  Since the varying magnetic field is synchronous with the operation of the circuit, whatever possible effects it could induce will seamlessly blend in with the operation of the circuit.  This is also the distinct possibility that any effects would be minimal one way or the other.  There are no big wire loops in .99's setup to "catch" the changing magnetic flux from the load resistor.  None the less, it would not hurt matters to displace the load resistor so it is not directly over the PCB.

.99 and Hoppy:

I am surprised the grounding improvements had much of an effect.  There are essentially no currents in the ground connections associated with the probes, so you would assume that the probe grounds can't induce any ripple effects in the ground voltage.  There are a few pretty sharp edges though starting with the 555 waveform on down.  Perhaps there are some localized very high harmonic frequency effects associated with the sharp edges that were reduced in amplitude with the improved grounding arrangement.

This is starting to make me think of my two microwaves courses, where the professor reminded us that all general circuit analysis is just a generalization of microwave theory where the frequencies are normally low enough so you could ignore the microwave transmission line effects.  I should never have taken Microwaves II, big mistake!  lol

Paul:

Just measuring the temperature of the load resistor at thermal equilibrium is essentially the same thing with the added benefit that it is much easier to do.  Measuring how fast the components heat up is just the thermal power integrated over time.  Most people are just measuring the thermal power.

MileHigh

MH

As a retired Telecomms Engineer and I've learnt a few things about the problems poor grounding arrangements can cause even at relatively low frequencies. I really whince when I see setups like Aaron displayed on the energetic forum. Its not just a case of common point starred ground connections being needed, equalisation of ground conductor lengths is also important as is conductor size, which should be as heavy as is practical to use. All components leads on the power side such as mosfet pins and shunt resistor leads need to be clipped short before termination. Poynt99 also points out the importance of probe placement. Its no good scoping any component with the probes anywhere but at the closest possible point to the body of the component if very accurate measurements are needed for detailed analysis. Until all setups are carefully built taking all this into consideration, test results will be contentious to say the least.

Hoppy

[poynt99]

A confirmation of the results from Glen's test #5. I crunched only Hour 2 for the 2us and 20us runs. All powers calculated (for a complete perspective), not just POS.

2_2us_520V-02_10_11_09.xlr

POS = -3.206W
PIL = 112.3W
PIM = -116.5W
PIS = 0.95W

Final resistor temperature = 135ºF

2_20us_520V-02_10_11_09.xlr

POS = -4.046W
PIL = 100.8W
PIM = -105.7W
PIS = 0.87W

Final resistor temperature = 136ºF

Again, I ask Glen, Harvey, and Rose to explain the 100W PIL when clearly the load resistor is not dissipating this much power

.99

[fuzzytomcat]

Examine this one.

1) You have two long croc-type leads to your resistor that run to a connector. I would guess around 24" each. Solder those leads to your resistor mate and get rid of the croc ends. Also, those leads appear under-gauged and are too long. Use multi-strand #12 throughout.

2) You have from this connector another long run to your battery bank, I would guess about 36" to the floor. The "battery" voltage is being taken from some point in the middle of this long run as shown on the butt connector. Incorrect. To properly measure the voltage across the load your two probes need to be right on the resistor ends as I show in my setup. The high side is your "battery" voltage, the low side the Drain voltage (reduce those lengths). See my test plan. That is how the wiring and measurement points should be set up.

3) You have two different probe ground points; one on the butt connector from the battery, and one star point ground going to your shunt (and you say I have ground loops ). This is a no-no, as I have found and emphasized here. One good ground point, and this should be at the -'ve side of the shunt with a heavy multi-strand wire. That little white ground wire going to your shunt is not adequate as I have noted.

You want to know why your results are skewed, this is most likely it. Clean up your grounding as I have and as I've just suggested, then see if your results are the same.

There is more I could suggest, but that will keep you busy for a bit should you choose to clean up your setup. I will also be trying a few more things to clean mine up as well.

.99

As your aware there was a video tape taken some of which has been posted "showing" relevent details of the test.

THE FIRST -
http://www.youtube.com/watch?v=BBIpSBjYDsQ

This shows the data collection "ONLY" 2 minutes before and through the process in HQ YouTube video with the file names ,time stamp and file size of all data collected - 21 images and 21 data dumps for verification purposes on the 6 hour run with 7 image and data collections

THE SECOND -
http://www.youtube.com/watch?v=ZM8BBa7_Zpc

The same content of the first video but with extra set-up footage and final extra image collection prior to stopping the test after 7 image and data collections.

THIS HAS BEEN POSTED HERE ALREADY AND THE BATTERY IS NOT ON THE FLOOR !!!!!!

There is a video I'm working on approx 40 minutes long in HQ (5 GB) from beginning to end when fully edited it will be posted on a P2P torrent site. This has 2 minutes prior to image and data dumps and 2 minutes after hour 1 through hour 4, hour 5 through the final 7th finish data and image collection has the exact same thing with added set-up footage and return to tri pod for several minutes ...... Fully Documented .... lower quality footage will be posted on YouTube when completed.

And for ground loops ...... your scope probes are connected to the wall outlet 120 volt plug ground and going to a AC grounded system ...... you have a separate earth grounding point at the dual power supply connected to the Rosemary Ainslie COP>17 Heater 24 volt circuit grounding it to what a AC grounding system ..... talk about ground loops and potential differences

[poynt99]

And for ground loops ...... your scope probes are connected to the wall outlet 120 volt plug ground and going to a AC grounded system ...... you have a separate earth grounding point at the dual power supply connected to the Rosemary Ainslie COP>17 Heater 24 volt circuit grounding it to what a AC grounding system ..... talk about ground loops and potential differences

My circuit is connected to the Grid ground through the oscilloscope. I agree with you on that.

However, check the power supply photo again, you are incorrect about it being tied back to Grid ground there. The green banana jacks are earth ground, the black ones are isolated grounds, even from each side of the supply. I have tied both sides (the 12V 555 supply and the 25V load supply) together right at the supply as you can see by the heavy black wire connecting the two black banana jacks. I have no connection to the green ones at all.

Before I built Groundloop's PCB, I severed a ground connection on the PCB between the load and 555 side as this would have caused a ground loop (ironically) in itself.

I have no groundloops mate, but with your double probe grounding I pointed out, indeed you do.

.99