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Author Topic: Itsu's workbench / placeholder.  (Read 138170 times)
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Hi Itsu,

Oscillators tend to behave sensitively to a changing internal resistance or impedance of the power supply feeding them.  And ampermeters in series with a supply rail increases that resistance or impedance. This is why many oscillators are run from a dedicated on-board voltage regulator built close to it, whose output resistance or impedance can be more constant. 
The same can be valid for a series resistance used for current sensing in one of the supply rails, when inserted, the oscillator may change its behaviour.

Thanks for these efforts.

Gyula
   
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   That is also what I've noticed, concerning connecting up a meter or a scope to this type of sensitive circuits, to test for voltage or current.
   Which brings us back to obtaining self running, first. Then see if there is any chance of testing for values, second.
   What I and others have done is to not use the negative probe on the scope. That may make the signals look a bit strange, but then they will be off if the ground is connected, also.  I know that itsu is aware of that. I'm just restating it, in my own way. So, why not test for self running?
   You never know. But it seems like a lot of voltage at the output, perhaps a proper feed back path may show something interesting. Or not.
   

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Hi Gyula,

i quickly used my old Fluke 8060A true RMS DMM instead, and it showed the same behaviour as with the cheapo M890G DMM.

But when using the newer Fluke 179 true RMS DMM, i get NO change in the current AND no change in the PS voltage or current readings! (no change means a few tenth of mA's, like 29.4 without and 29.7 with).

It seems the newer Fluke filters out the RF going into the PS.

I will take some scope measurements tonight to see how this Fluke meter influences the RF feedback.

Thanks,   Itsu

Ok,  tried again the above, but now with my scope powered on to see the signals.

Unfortunatly, the Fluke 179 also shows the same behaviour as the M890G and the Fluke 8060A, RF feedback into the PS.

The problem was the ground lead of the scope probe.
When disconnected (which it was during my earlier Fluke 179 test) the RF feedback is NOT there, so when the scope probe is disconnected i can not invoke the RF feedback into the PS when the output lead is connected to the input positive.
The input current signals and amplitude stays the same around 30mA with or without connection output to input.

So somehow the grounding of the L3 enables the RF feedback allthough my PS (return lead) is not grounded.

Complicated stuff.


Regards Itsu

 

   
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Hi Itsu,

Will try to digest this tomorrow. 

Thanks and good night.

Gyula
   
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Ok,  tried again the above, but now with my scope powered on to see the signals.

Unfortunatly, the Fluke 179 also shows the same behaviour as the M890G and the Fluke 8060A, RF feedback into the PS.

The problem was the ground lead of the scope probe.
When disconnected (which it was during my earlier Fluke 179 test) the RF feedback is NOT there, so when the scope probe is disconnected i can not invoke the RF feedback into the PS when the output lead is connected to the input positive.
The input current signals and amplitude stays the same around 30mA with or without connection output to input.

So somehow the grounding of the L3 enables the RF feedback allthough my PS (return lead) is not grounded.

Complicated stuff.


Regards Itsu

Itsu ,
Thanks by your efforts , and i really understand when you say "complicated stuff "  sometimes i have the same feel , but well ,If it were easy, anyone already would have understood, and that alone is what motivates us not to give up on learning :).
Have a good night !


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Nelson Rocha

" The goal is not to be successful, the goal is to be valuable.
Once you’re valuable, instead of chasing success,
it will attract itself to you. "
   
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Hi Itsu,

Okay on the ground lead left connected earlier and now, when disconnected,  the feedback into the PS is over.

If I understand you correctly, you connect the positive output of the diode bridge back to the positive input supply rail, right?
i.e. it is not the AC output from one of the L3 wire ends which is tied back.

This is what I first assumed (mistakenly) from Nelson's video,  he showed the AC output across L3 on the scope and the feedback was from the positive output of the diode bridge.  Maybe seeing the waveform across the DC output of the diode bridge could reveal something useful when the feedback is made. I think of the low value (100 nF)  puffer cap across the DC output : it may prove to be a small value for adequate filtering when the loading effect (if there is any)  of the  feedback manifests.

So with your setup, now that there is no ground lead problem, the connection of the positive output back to the positive input rail has no any effect:   input current waveform and amplitude would not change, right?

So there remains to figure out why the oscillator at Nelson behaves differently. Perhaps the leakage inductance of his 1:1 transformer (L2/L3) differs much from that of your 1:1 transformer. 

Thanks
Gyula
   

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Gyula,

Quote
If I understand you correctly, you connect the positive output of the diode bridge back to the positive input supply rail, right?
i.e. it is not the AC output from one of the L3 wire ends which is tied back.


No, i (and Nelson as i understand) do NOT connect the positive output of the diode bridge back to the positive input supply rail.
I connect one side of L3 (so one side of the AC input of the bridge) to the positive input supply rail.

This L3 or the AC side of the bridge has these positive spikes/signals seen as yellow on my screenshots.
I connect the positive side of this L3 / AC bridge signal to the positive input supply rail.


Quote
So with your setup, now that there is no ground lead problem, the connection of the positive output back to the positive input rail has no any effect:   input current waveform and amplitude would not change, right?


Right.

As mentioned, my PS itself is grounded, but the internal PS's are floating, so the minus have no link to the earth ground.
In my setup, only the scope ground leads are earth ground connected, so when using only 1 probe at a time it should have no influence, but appearently it does.


Itsu
   
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Gyula,


No, i (and Nelson as i understand) do NOT connect the positive output of the diode bridge back to the positive input supply rail.
I connect one side of L3 (so one side of the AC input of the bridge) to the positive input supply rail. 

Okay Itsu, thanks for clarification.  I wonder what Nelson will say on his hook up in this respect.    8) 

Quote
This L3 or the AC side of the bridge has these positive spikes/signals seen as yellow on my screenshots.
I connect the positive side of this L3 / AC bridge signal to the positive input supply rail.

Perhaps the text I put in bold has caused my misunderstanding.  (You mentioned it like that in the video too.)

Greetings
Gyula
   

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Gyula,

no problem, i often have problems with written text only, i like to see diagrams and pictures/video's as they normally avoid such misunderstandings.
I see where your misunderstanding could come from looking at my bold text above.


It could be though that i did misunderstand Nelson in his video about how he hooked up the led bulb and the feedback wire to the positive input rail, hopefully he can clear that up.

Itsu
   
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Hello Itsu and Gyula,
sorry I haven't answered yet but this week has been tough, especially when working 12 hours with temperatures over 30 degrees on last days .
I will try to answer in general and synthesized the posts that you both published.

I connect the positive output of the diode bridge back to the positive input supply rail.
The oscilloscope is connected to the output of the L3 transformer, which connects to the diode bridge input in other words is connected to AC source.


My oscilloscope has its transformer connected, for convenience to charge the scope when i need,  in a socket that i can turned on/off by a switch, but even if turned off on the switch, the ground of the socket itself apparently causes this effect, because if the socket is completely disconnected, the effect is almost imperceptible on the bulb.
If I disconnect the ground probe from the bridge the effect stop, as you could see in your previous video, but the curious is if i invert  the probe position in legs of input bridge the effect stop .
I also tested a direct ground with a wire of more than 10 meters and the effect remains without apparent in the bulb without changing the output voltage.
In My studio I have an electrical panel made for convenience, with devices to prevent electrical discharges, (surge protective device), as well as an active current monitor, Watt meter, reactive measure etc.
It would be supposed not to happen this type of passage on the ground because it is a real ground and not connected with neutral as it happens in some cases.
Maybe they can be skin effect given the frequency involved?
I leave another video with other aspects observed but it was done after realizing the issue of ground on the scope.
https://photos.app.goo.gl/NsGLqXkhG7ouhinh7


https://photos.app.goo.gl/UXPK54AqtgFU9a3t6



Best rewards:

Nelson Rocha


---------------------------
Best Rewards
Nelson Rocha

" The goal is not to be successful, the goal is to be valuable.
Once you’re valuable, instead of chasing success,
it will attract itself to you. "
   

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Hi Nelson,

Quote
I connect the positive output of the diode bridge back to the positive input supply rail.
The oscilloscope is connected to the output of the L3 transformer, which connects to the diode bridge input in other words is connected to AC source.


Ok,  thanks for clearing that up.


Also thanks for showing these nice effects with the ground.
Welcome to the wonderfull world of RF i would say  :)


Itsu
   
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Hi Nelson,

Ok,  thanks for clearing that up.


Also thanks for showing these nice effects with the ground.
Welcome to the wonderfull world of RF i would say  :)


Itsu


Hi Itsu ,
I would like to add that if the probe is placed at the exit of the diode bridge rectifier, where it is supposed to be DC, the same behavior occurs, this leads me to conclude that there may be a very large margin of difficulty in making measurements correctly  if the equipment does not be properly isolated from the ground.
Perhaps it is time for me to put an inverter to power my equipment's, in order to exclude the possibility of inducing false values during measurements.
Are your equipment (scope) completely isolated from the ground or does it have a floating ground?
thanks


---------------------------
Best Rewards
Nelson Rocha

" The goal is not to be successful, the goal is to be valuable.
Once you’re valuable, instead of chasing success,
it will attract itself to you. "
   

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Nelson,

well this situation is new to me and i would like to ask some more people to step in here to explain.

My PS is connected to ground, but its outputs are floating, so the minus leads are NOT connected to earth ground like a battery would.

But my FG and scopes are normally grounded and the ground leads are all on that earth ground level.

So therefor i always watch out with multiple scope probes and/or the FG leads where to put their ground leads so to NOT interfere with the measurements.

But here i only used 1 scope probe so i was convinced this would have no impact on the measurements or behaviour of the DUT, but appearently the latter is the case here.

A ground (in my case the scope ground lead ground) alters the behaviour and thus the measurements.

Its a lesson for me which i need to remember for future measurements.

There is a lot to be found on the net about isolating the DUT or the measurement device (scope / FG), but in general the idea is to isolate the DUT and NOT the measurement devices i think.

Regards Itsu
   
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Hi Nelson,

It is good that the ground on the sockets has no connection to the neutral wire of the mains in your home (if that is what you meant).

Hopefully, there is no any other household applience in your home either,  which has a poor or damaged isolation between its ground and the neutral connections which may willy-nilly 'provide' an unwanted direct connection or only a a few kOhm 'leakage' resistance or impedance between the neutral and the ground at the sockets. 

Regarding the strange behaviour of the scope's ground probe i.e. when you "invert the probe position" at the AC input legs of the diode bridge and the effect stops,  I think the following:

In an oscillator circuit the components are connected to either a low or a high impedance circuit point with respect to the DC supply rails.  Also the components can have either a low or a high oscillating voltage across them, also with respect to the supply rails but of course this can be true directly across a particular component.
So when the ground probe of the scope is connected to the 'high' voltage point of L3 (which is also one of the AC diode bridge inputs),  the available voltage difference to drive current into the 'ground' connection will be higher (to better initiate the effect) than in the case the ground croco is tied to the other end of L3. You may say that L3 is totally ground independent because it is inductively coupled to L2 but L2 is already directly connected into the circuit and the leakage inductance and stray capacitance between them may transfer the low and high voltage differences of L2's legs to L3 legs with respect to the ground rails.  (The voltage difference across L2 is transformed normally, of course,  L2/L3 being a 1:1 transformer.) This is how I think this can happen.

You also posted this:
"I would like to add that if the probe is placed at the exit of the diode bridge rectifier, where it is supposed to be DC, the same behavior occurs,"
Well, if my approach to explain this behaviour when the probe ground was at the input of the diode bridge is correct (what I think it is),  then it should be valid for the output side of the diode bridge because the diodes conduct alternately of course, connecting L3 legs to the DC output.
Note C7 may have a role in this too,  for it directly shunts one of the bridge diodes,  albeit a 4 nF has about 2 kOhm capacitive reactance at 19 kHz, so may not be too significant (but it is present and 2 kOhm is not high to limit current when the peak to peak AC voltage is around 300 V).

The use of an inverter to supply ground independently your measuring instruments sounds good. 
Another note:  For your own safety, if your device under test is run from the mains and you need to tinker on it, the use of an inverter or an 1:1 isolating mains transformer is also a good idea (the latter is perhaps the best).

Regards and have cooler weather.   8)

Gyula
   

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Believing in something false doesn't make it true.
I hope you guys don't mind if I add a thought or two.  If I understand correctly Itsu you are saying your ground pin of your wall socket is NOT connected to the neutral pin in your home?  Is that correct?  I thought according to code, at least in the U.S. all homes had to have the neutral line connected to a ground rod driven deep into the ground near the incoming power.  And inside the main breaker box the neutral and ground busses are tied together so in effect all ground pins in the receptacles are connected to all neutral pins.

I once had to work on a problem with a new installation of an automated storage and retrieval system.  The computer systems kept going crazy and shutting down.  When I checked the 110 vac going to the system the voltage was almost dead on.  But when I checked the neutral to ground there was a difference of almost 250 volts!  The installer had failed to tie the secondary of the step-down transformer to ground so the 110 vac was floating in reference to ground.  And this was causing all the problems.  Once I grounded the secondary then everything settled down and worked fine.

One more thing and I will shut up.  We sometimes had to work on motor controls that had no transformers in the supply side.  To keep from blowing up our scopes we used for troubleshooting we made up some very short cables with male and female 110 vac connectors but left out the ground connection.  Worked fine for trouble shooting.  But I agree with Gyula a 1:1 isolation transformer is the best thing to use in this type of situation.

Respectfully,
Carroll


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Hi CITFTA,

i appreciate your commenting,  thanks.

But to be clear i did not say anything about our ground pin of our wall socket being connected (or not) to the neutral pin in our home.

I mentioned that my DC Power Supply (with 3 PS's in 1) is, as normal, connected to earth ground at its socket, but that the 3 PS's are floating from that earth ground, so their minus leads are NOT connected to earth ground.


But i understand that where i live (The Netherlands) our ground pin of our wall socket is NOT connected to the neutral pin in our home.

It is tight together at the Power company only.


Concerning the 1:1 isolation transformer, i understand the rule is to use it on the DUT, not on the measuring equipment (when possible).

Regards Itsu
« Last Edit: 2020-05-30, 16:17:28 by Itsu »
   
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Regarding electrical supply systems (mains networks)  I think we all need to be aware of the ground ( in British English this term is earth  8) ) and neutral wire relation at our own location, in our own country.  Standards  may differ in this respect.

Gyula

   
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Hi Nelson,

It is good that the ground on the sockets has no connection to the neutral wire of the mains in your home (if that is what you meant).

Hopefully, there is no any other household applience in your home either,  which has a poor or damaged isolation between its ground and the neutral connections which may willy-nilly 'provide' an unwanted direct connection or only a a few kOhm 'leakage' resistance or impedance between the neutral and the ground at the sockets. 

Regarding the strange behaviour of the scope's ground probe i.e. when you "invert the probe position" at the AC input legs of the diode bridge and the effect stops,  I think the following:

In an oscillator circuit the components are connected to either a low or a high impedance circuit point with respect to the DC supply rails.  Also the components can have either a low or a high oscillating voltage across them, also with respect to the supply rails but of course this can be true directly across a particular component.
So when the ground probe of the scope is connected to the 'high' voltage point of L3 (which is also one of the AC diode bridge inputs),  the available voltage difference to drive current into the 'ground' connection will be higher (to better initiate the effect) than in the case the ground croco is tied to the other end of L3. You may say that L3 is totally ground independent because it is inductively coupled to L2 but L2 is already directly connected into the circuit and the leakage inductance and stray capacitance between them may transfer the low and high voltage differences of L2's legs to L3 legs with respect to the ground rails.  (The voltage difference across L2 is transformed normally, of course,  L2/L3 being a 1:1 transformer.) This is how I think this can happen.

You also posted this:
"I would like to add that if the probe is placed at the exit of the diode bridge rectifier, where it is supposed to be DC, the same behavior occurs,"
Well, if my approach to explain this behaviour when the probe ground was at the input of the diode bridge is correct (what I think it is),  then it should be valid for the output side of the diode bridge because the diodes conduct alternately of course, connecting L3 legs to the DC output.
Note C7 may have a role in this too,  for it directly shunts one of the bridge diodes,  albeit a 4 nF has about 2 kOhm capacitive reactance at 19 kHz, so may not be too significant (but it is present and 2 kOhm is not high to limit current when the peak to peak AC voltage is around 300 V).

The use of an inverter to supply ground independently your measuring instruments sounds good. 
Another note:  For your own safety, if your device under test is run from the mains and you need to tinker on it, the use of an inverter or an 1:1 isolating mains transformer is also a good idea (the latter is perhaps the best).

Regards and have cooler weather.   8)

Gyula

Hi Gyula ,
Thanks by your opinion about this subject .

“Hopefully, there is no any other household appliance in your home either, which has a poor or damaged isolation between its ground and the neutral connections which may willy-nilly 'provide' an unwanted direct connection or only a a few kOhm 'leakage' resistance or impedance between the neutral and the ground at the sockets.”

After this point that you mentioned, I decided to measure the potential involved between neutral and earth in my house.
I measured all the available sockets as well as the General electrical panel where the connections with the electrical supplier are located, including the ground connection.
The measured values ranged from 0.4V to 0.5V, these being the values recommended by prevailing legislation in Portugal, and result from the capacitance created by the two adjacent conductors of the ground and neutral wire.
The recommended maximum values are located at 2.5v, above this value it may indicate an anomaly.
This clearly demonstrates a total isolation between neutral and earth :).
For this reason I will be able to say that everything is correctly with my earth connection.

In the past I had an excellent isolation transformer, which unfortunately I was unable to bring from Germany, do it with the costs involved in its transport (20kg) but had a wide range of primaries and secondaries, which facilitated in some tests where it involved voltages above the grid publishes.
But I do agree that it will be the best solution to try to discard some variables that could induce errors during measurements.
I will do some more tests that I will publish if they are interesting for this topic.
Have a nice weekend ;)


---------------------------
Best Rewards
Nelson Rocha

" The goal is not to be successful, the goal is to be valuable.
Once you’re valuable, instead of chasing success,
it will attract itself to you. "
   
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Hi CITFTA,

i appreciate your commenting,  thanks.

But to be clear i did not say anything about our ground pin of our wall socket being connected (or not) to the neutral pin in our home.

I mentioned that my DC Power Supply (with 3 PS's in 1) is, as normal, connected to earth ground at its socket, but that the 3 PS's are floating from that earth ground, so their minus leads are NOT connected to earth ground.


But i understand that where i live (The Netherlands) our ground pin of our wall socket is NOT connected to the neutral pin in our home.

It is tight together at the Power company only.


Concerning the 1:1 isolation transformer, i understand the rule is to use it on the DUT, not on the measuring equipment (when possible).

Regards Itsu

Hi Itsu ,
The same happens in my home in Portugal in general  with exception in rural areas  .
The ground connection here in Portugal is also completely independent of the neutral. I think this practice has been adopted in recent years to prevent ground loop and other events such as parasitic noise in household appliances.
Well i need dig more this subject matter.
I wish you a great weekend



---------------------------
Best Rewards
Nelson Rocha

" The goal is not to be successful, the goal is to be valuable.
Once you’re valuable, instead of chasing success,
it will attract itself to you. "
   
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   Yes, and those "ground loops" can be devastating. We do have that problem here, with the houses that have both 220v and 120v on the same installation. If the ground line gets too resistive due to corrosion, the 220 will jump over to the 120 side, and bang, there goes all the lights and everything that is not 220v, up in smoke. And also, there is considerable stray AC, throughout the wiring in my house. Even on the floor, tables, etz... even with two grounding rods outside. Although the humidity, rain, and salt from the beach, may have something to do with it.
   
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Hi Nelson,

If you can scavenge two mains transformers from some dysfunctional and old microwave owens, then connecting their HV secondaries together, (back to back) you would have eventually a 230 V in and nearly 230 V output isolation transformer.    C.C

The latest microwave owens nowadays have a switch mode power supply...   this is why I wrote old types (from junkyards or service shops).

Have a good weekend too.
Gyula
   
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The latest microwave owens nowadays have a switch mode power supply...   this is why I wrote old types (from junkyards or service shops).

...and municipal recycling centres. (For legal reasons, be certain to say they are wanted for spares only - which is true - but needs saying).
   

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Placeholder for a picture concerning the "Manelas device":





Smudge,

did you see this email exchange about the manelas device here:

https://www.mail-archive.com/vortex-l@eskimo.com/msg113512.html      (press "Next Message" to read on).


Itsu
« Last Edit: 2020-06-08, 20:53:02 by Itsu »
   

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I was planning to return to OU.com to do a revisite of the original "Dally nano-pulser" (using his original parts) in the: "Kapanadze Cousin - DALLY FREE ENERGY" thread and to join the threads opened there by Smudge (NMR) and Partzman.

But looking at the latest posts overthere, i can't help to notice that still that Forum is "under siege".
Untill that is corrected i will refrain from posting there.


Instead i will report my results on the Dally nano-pulser here and also try to contribute from here to the above mentioned threads by Smudge and Partzman.

Itsu
   
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I was planning to return to OU.com to do a revisite of the original "Dally nano-pulser" (using his original parts) in the: "Kapanadze Cousin - DALLY FREE ENERGY" thread and to join the threads opened there by Smudge (NMR) and Partzman.

But looking at the latest posts overthere, i can't help to notice that still that Forum is "under siege".
Untill that is corrected i will refrain from posting there.


Instead i will report my results on the Dally nano-pulser here and also try to contribute from here to the above mentioned threads by Smudge and Partzman.

Itsu

Itsu,

I understand and agree with you wholeheartedly.  There is an individual who seems to try to disrupt certain threads with the same old clip art and then belittles anyone questioning his lack of production of a valid OU device which he claims he and his followers have an abundance of!

Until he is put under control by Stefan, I refuse to post any info there as well.

regards,
Pm
   
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