What am I doing wrong with this PSpice design 4

[LucasBS]

Look at the picture

https://www.dropbox.com/s/aju24pifejxsyxx/PSPICE1.png

I cannot put a simple Source+resistor to work

Parts are filtered to containing PSpice simulation

Source: Vac
2x Analog: R
Default Grounding

Tried changing the values of the source to 1000V, 1000Vac, etc... Nothing

 

[IRstuff]

What exactly did you expect to happen?

Are you measuring AC or DC> In either case, there should be zero volt DC drop across both resistors, as specified.

TTFN
faq731-376

Need help writing a question or understanding a reply? forum1529

 

[LucasBS]

There suppose to be a sine wave with a thousand volts of peak on the test probe, isn't ?
Well, thousand on the positive cycle, and a little bit less than that on the negative cycle

 

[IRstuff]

and a little bit less than that on the negative cycle ??

Huh? A/C is A/C.

I suggest you get an EE in your company to help you out.

TTFN
faq731-376

Need help writing a question or understanding a reply? forum1529

 

[LucasBS]

A/C is A/C if there is no neutral draining one of the half.
That is why the large resistor

https://www.dropbox.com/s/0wqu4coiyop7zyh/Circ1.png

In this picture the pot is at 1M config., which is invisible to the source
The multimeter says 24 Vacpp difference of potential. So as should PSpice.

 

[Skogsgurra]

Dear Lucas

Are you the same Lucas that invented darkness? Sorry, couldn't resist.

All your assumptions seem to be based on misconceptions. Your best bet is to follow IR's advice.

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[IRstuff]

"The multimeter says 24 Vacpp difference of potential. So as should PSpice."

NO!! PSpice cannot read your mind nor can it produce results for something that is not on the schematic. If you are showing a potential across the bottom resistor, then you have capacitive coupling or leakage that is not reflected in your drawing.

TTFN
faq731-376

Need help writing a question or understanding a reply? forum1529

 

[itsmoked]

LucasDemh; Check your settings. There should be 1kV where the probe is, if pspice works like I think it does.

Looking at the picture you posted shows "5something" in the run time window. Could that be an invalid character?

You really only need to run that simulation for a few cycles and you should "save results" starting immediately.

Or perhaps you've put a reference probe that's invisible on that top wire.

Consider scrapping this entire episode and on a new screen do it over from scratch. And skip the 1M resistor. See what happens.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[LucasBS]

Lol
Never heard of this darkness inventor until now. Good jokes. Just wonder why they picked up my name for it.

I did not mention, but I remade the physical testing without the ground resistor and the zero volt wire (literally, only the transformer and a resistor, then), still resulting on a sine wave on the oscilloscope.
Also, the picture does not show, but I DID connect the ground clip of the oscilloscope probe on the brown of the transformer. Only the amplitude of the sine reduced.

"PSpice cannot result for something that is not on the schematic"
The physical model works perfectly. And please correct me, it is exactly as on the simulator proposition.

Perhaps PSpice reads the average voltage on that node. OK, the average of a sine IS zero. But that probe should act as a oscilloscope, right ? plotting the whole specter.

I agree ! there should be 1kV sine there.
I re-designed from scratch the same circuit on PSpice, without the resistor between the ground and the line.
Tried putting a oscilloscope-like probe, just like the first picture, and a difference of potential-like probe, soon after. Both result zero. CONTRADICTING the physical thing.
Tried even putting a current marker there. Resulting zero.
My conclusion is that the source is dead, somehow.

Corrected the simulation to start reading from zero until 3 seconds (without the 's' character). Nothing changed.
Apart from that, what other configs are there ?

 

[itsmoked]

I use LTspice and often the hardest part is setting all the buttons and switches correctly. Often I go thru a period of perplexment getting anything to appear.
Obviously your circuit is right. Obviously the logic is functional. That leaves only 'operator malfunction'.

Next suggestion: call up a simple PSpice example circuit that came with the program. Prove you can run that. Then twist it into your circuit and run it again.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[IRstuff]

Again, you should ask an EE in your company who is using that version of PSpice to check out. This is reminiscent of the way some women were diagnosed by a male doctor, who was not not allowed to actually examine the patient, but could only have someone else examine the patient and then report to the doctor.



TTFN
faq731-376

Need help writing a question or understanding a reply? forum1529

 

[jimkirk]

You're doing a Time Domain (transient) analysis.
The AC source is intended for doing frequency response analysis only (note that there is no frequency associated with the source).

Use a sine wave source, specifying amplitude & frequency, not an AC source.

 

[LucasBS]

You're saying that the EE will say ?
a) my logic is wrong.
or
b) the circuit is bad assembled.
or
c) PSpice is drunk
Which one ?

I stick with the C alternative, that's why I'm going to do what itsmoked says: compile another project to ensure it's not a bug.
I was thinking the same...

Only then I give up and call the doctor to see my 'parts'.

 

[LucasBS]

Oh, boy...

That explains a lot...

And right on time (before I started the trouble of opening another project)

The sine wave generator solution worked!
It's magic.

End of the problem. Thank you all.
Jim specially

 

[Skogsgurra]

I am very curious. Did you get the same result as you got IRL?

Like "The multimeter says 24 Vacpp difference of potential. So as should PSpice"

Did you really get that result from the simulation? Please show.

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[LucasBS]

Sure,

https://www.dropbox.com/s/ju76bm9ry3e2kvm/PSpice2.png

Observations:
- There is a 0V label hanging on the treads. It is a residual I did not remove from before, not representing the actual value.
- Removing that ground resistor did not change the result at all.
- The picture represents a simulation collecting data from 1s to 1.1s.
- The sine did reach the 1000 volt peak only when collecting data from 0s to 0.1s (Maybe too few samples on the plot gave a different peak when acquiring from 1 to 1.1s. Don't know how to change that)

 

[itsmoked]

Yay! Nice catch jimkirk.

I was right too! 'Operator Malfunction'

Well, you're on your way now.



Keith Cress
kcress -

http://www.flaminsystems.com

 

[Skogsgurra]

I see no 24 V there.

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[LucasBS]

True
The 24 Volts I used on the physical thing (a transformer), on the simulator I could put whatever I wanted. One thousand crossed my mind.
(You know... Zeus was not making 1000 volts thunders that day for me to put on my real circuit )

But the principle is the same: With the multimeter, what I get from the tip of the transformer is the same I get from the tip of the Sine source: the peak difference of potential (With or without any load attached to it), and whatever the potential.
With an Oscilloscope, I get the exact sine, without needing to contact both ends, also without load necessarily attached.


Living and learning...

Thanks guys.

 

[IRstuff]

"With an Oscilloscope, I get the exact sine, without needing to contact both ends, also without load necessarily attached."

Only because you've grounded the oscilloscope, which invalidates your schematic.

TTFN
faq731-376

Need help writing a question or understanding a reply? forum1529