pspice help

Thread Starter

KingD

Joined Mar 7, 2014
8
Okay so i have this circuit i am having trouble with, and no i am not building this
I am using a 34,500 AC voltage source that is stepped down to about 6000 VAC and rectified to a DC voltage source so it can charge up a large amount of capacitors.

Why am i getting negative numbers for voltage and amps?
that does not make any sense to me

Also, to get the voltage from 34.5k to 6k, how do i set up the transformer induction to do so?

Need this asap, i appreciate any sort of help.
I have taken 1 class for pspice, but it was only the basics.
 

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crutschow

Joined Mar 14, 2008
34,420
Those aren't negative numbers, they are very small positive numbers (meaning there is essentially nothing coming from the transformer secondary). Don't you understand scientific notation for numbers?

Not familiar enough with P-spice to know how transformers are characterized. Doesn't the program have a help file?
 

Thread Starter

KingD

Joined Mar 7, 2014
8
Those aren't negative numbers, they are very small positive numbers (meaning there is essentially nothing coming from the transformer secondary). Don't you understand scientific notation for numbers?

Not familiar enough with P-spice to know how transformers are characterized. Doesn't the program have a help file?
oh wow, my apologies, that is what i meant to say. I do understand scientific notation.

They are very small positive numbers, but that still does not make any sense to me.

It does, and i am actually going through it right now.
 

Thread Starter

KingD

Joined Mar 7, 2014
8
Also, no matter what value i change the AC voltage source to, the numbers that you see on the attachment, just stays the same.
Same with changing the inductance values on the transformer, the numbers stay the same.

I am not sure whats wrong.
 

Thread Starter

KingD

Joined Mar 7, 2014
8
R1, R4 and the transformer have no values assigned/marked. How can pspice make sense of that?
Oh didn't notice that, sorry once again.

But they do have values, i just checked
R1 and R4 both have values of 1k ohms

and the transformer value i just guessed on and put a random value just to see if it works. L1 500 uH, L2 100 uH

everything has values, but thank you for pointing that out
 

crutschow

Joined Mar 14, 2008
34,420
What is the input frequency? For power line frequencies you need transformer inductances in the henry region, not microhenry. You need to look at some real transformers to get some representative values. Guessing at values seldom gives good results in circuit design or simulation. :rolleyes:
 

LvW

Joined Jun 13, 2013
1,755
KingD, all the displayed values are dc only, which result from the calculation of the quiescent operating point (calculated prior to ac simulation). Since there is no dc source in your circuit all values must be zero (practically, e-27 is zero).
To verify the working of the circuit you must start a TRAN analysis (not ac, because ac is a linear small signal analysis only).

EDIT: Don`t forget to use an appropriate voltage source Vsin (NOT Vac).
 
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Thread Starter

KingD

Joined Mar 7, 2014
8
KingD, all the displayed values are dc only, which result from the calculation of the quiescent operating point (calculated prior to ac simulation). Since there is no dc source in your circuit all values must be zero (practically, e-27 is zero).
To verify the working of the circuit you must start a TRAN analysis (not ac, because ac is a linear small signal analysis only).

EDIT: Don`t forget to use an appropriate voltage source Vsin (NOT Vac).
ohhh that makes more sense. thank you

On the Vsin part, what is the difference between VOFF, VAMPL, AC
i have to input something for each one, but not really sure what.
i know the voltage source should be 34500V but not sure if that is VOFF, VAMPL, or AC
 

LvW

Joined Jun 13, 2013
1,755
ohhh that makes more sense. thank you

On the Vsin part, what is the difference between VOFF, VAMPL, AC
i have to input something for each one, but not really sure what.
i know the voltage source should be 34500V but not sure if that is VOFF, VAMPL, or AC
* Voff is a dc voltage. As a result, the specified sinus voltage is riding upon this Voff value. For a pure sinus wave Voff=0.
* Vampl is the amplitude of the input sinusoidal wave.
* AC is for ac analyses only. That means: This input source can be used for TRAN or AC analyses.
For TRAN: AC has no effect; for AC: Vampl has no effect.
 
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