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Building lt spice transformer / help!

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killivolt

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I can't do the Math or anything. It's one of the last things on my LT Spice Schematic.

Edit: Oh, and if you could go through the steps, I'm not sure if the Data will provide it all or what, I'm confused about the hole process.

Data Sheet of the Ferrite Core.

**broken link removed**

Here is the Schematic I have pulled off some of the values off the data sheet and put them on the schematic. I could sure use someone who could get this thing put together, maybe after I have a year or so practicing my maths I might have a go at it. But not at the moment.
 

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Not quite sure what you're after, but to sim a transformer just place two inductors L1, L2 on the sheet and a command 'K1 L1 L2 1'. The inductor ratio is the square of the turns ratio.
 
In this case I have 4 wires 14 turns so in order to get L "u" the square of 14 is 196u correct ?
 
Sure:

i) Measure winding L's with a DC LCR meter. Use these values directly in simulation.
I don't have a DC LCR meter, I have a DM,

ii) Measure winding ESR with an ohmmeter. Use twice these values in simulation since the resistance at frequency is higher than the DC value. My experience with ferrite and switchers is that it is usually nearly a factor of two higher.

So, I'm just measuring resistance? At a Factor of 2 or higher correct?

) Short all but most inductive windings and measure the leakage inductance with the DC LCR meter. Adjust the coupling coefficient to match this, or for the case of two windings:
K = sqrt(1-Lleak/sqrt(L1*L2))
Lleak = sqrt(L1*L2)*(1-K*K)

This is where I go, what the heck are they talking about?

iv) Find the transformer's resonate frequency and Q. Specify a Cpar and Rpar for the most inductive winding to match this resonance.

Heck, I have to find a DC LCR meter first.

v) Enjoy.

Thanks, good knowing you.

Sorry for the sarcasim but, I'm so lost?
 
I have 4 wires 14 turns so in order to get L "u" the square of 14 is 196u correct ?
Sorry, I don't understand that. What is 'u'? In Spice you specify the inductance of L1 and L2. If, for example, you specify L1=16mH and L2=1mH that corresponds to a L1:L2 turns ratio of 4:1
 
Post #4 is from the help file in Spice, I don't have an LCR meter however I do have the Core Data sheet and # of turns and voltages, still beyond that I'm confused how it all fits together.

Ron, I'm building this to find out if the circuit will function or not. I have already wound the Transformer.
 
To get the inductance of a coil, you take the Al value for the core from the datasheet and multiply that by the square of the turns.
 
Sorry, I don't understand that. What is 'u'? In Spice you specify the inductance of L1 and L2. If, for example, you specify L1=16mH and L2=1mH that corresponds to a L1:L2 turns ratio of 4:1

I don't have any idea of L1 or L2 mH, I know that the core is at 4620 nH? How can I without an LCR meter ( only using) the Data sheet and the known V, #windings, permeability N30 at 25%, and Magnetic Characteristics from the Data sheet complete input needed for the Transformer in LT Spice?
 
Finally.

Thank you, ChrisP58

You guy's are killing me, but I like it:)

kv
 
Sorry, I don't understand that. What is 'u'? In Spice you specify the inductance of L1 and L2. If, for example, you specify L1=16mH and L2=1mH that corresponds to a L1:L2 turns ratio of 4:1


You guy's in the UK are funny, I don't like it, but your still funny, having fun at my expense.

I know you will deny it, I've been there done that, haha.

I still like you and enjoy reading your post's. I'm not sure I would have even been seen, had you not post.

kv
 
Wow, so 14 squared 196 and the square root 14 is 3.74

196 x 4620 = 905520 or 3.74 = 17279 now I need the series resistance and Parallel Resistance and figure K, L1, L2, L3, L4, ()

Which is it sqroot or squared?
 
u in LTSpice is the abbreviation for 1e-6, just like m is for 1e-3 and n is for 1e-9. If you want 1e6, you have to write it as Meg or meg.

The inductance of an inductor could be 0.0000013 or 1.3e-6 or 1.3u or 1.3uH (in the last case, the H is actually ignored)

As to your other questions, look at this
 
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u in LTSpice is the abbreviation for 1e-6, just like m is for 1e-3 and n is for 1e-9. If you want 1e6, you have to write it as Meg or meg.

The inductance of an inductor could be 0.0000013 or 1.3e-6 or 1.3u or 1.3uH (in the last case, the H is actually ignored)

Mike, sorry. That was way over my head, how do I deal with post #12 and talk like I'm 13 years old. When I edit the coil in LT Spice I need the values of

Inductance [H]

Series Resistance

Parellel Resistance

How do I aquire those. I'm flayling here and not landing on anything?
 
Your core has an Al value of 4620nH

14 turns ^2 = 196

196 * 4620^-9 = ~900uHy for each of your 4 windings.

Add a spice directive (like alec_t said in post #2) of "K1 L1 L2 L3 L4 .995"

The number at the end is the coupling efficiency. 1 implies 100%. A more practical value would be .99 to .995

If you have more than one transformer in a circuit you would have more K directives.
K2 L5 L6 .995
K3 L7 L8 L9 .995
etc.

Series resistance is the DC resistance of the winding. It's not critical for your transformer, but put in 10 milliOhms as a rough estimate. Leave parallel resistance open.
 
Follow the link in post 13. It tells you how to calculate the approximate inductance of your winding. For starters in LTSpice assume the series resistance of a winding is the same as you would measure with an Ohmmeter, Ignore Parallel resistance for now.
 
Thank you both.

You are going to make this a good Christmas for my friends. I plan to build 2 of these Plasma Speakers and give them for Christmas.

Thank you so, much.

kv

Edit: Only if I can make this darn circuit, work.
 
Your core has an Al value of 4620nH

14 turns ^2 = 196

196 * 4620^-9 = ~900uHy for each of your 4 windings.

Add a spice directive (like alec_t said in post #2) of "K1 L1 L2 L3 L4 .995"

The number at the end is the coupling efficiency. 1 implies 100%. A more practical value would be .99 to .995

If you have more than one transformer in a circuit you would have more K directives.
K2 L5 L6 .995
K3 L7 L8 L9 .995
etc.

Series resistance is the DC resistance of the winding. It's not critical for your transformer, but put in 10 milliOhms as a rough estimate. Leave parallel resistance open.

Right now I'm not worried at all about the HV winding.

Thanks again.
kv
 
I'll get back to you on it, once I have completed it, for correction.

Chris, on the Transformer I wound, will I want to tie 2 and 3 or would I tie 2 and 4?


kv
 
I'll get back to you on it, once I have completed it, for correction.

Chris, on the Transformer I wound, will I want to tie 2 and 3 or would I tie 2 and 4?


kv

?? I'm not sure what you mean by 2, 3 and 4.
 
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