Has anyone tried to define more than one coupled inductor?

Example,

Place spice directive:

K1 L1 L2 1.

This couples L1 to L2 with coefficient 1.

Now, if I place

K2 L2 L3 1.
This couples L2 to L3.

This gives strange results... but K1 L1 L2 L3 1. appears to work ok.
However, I dont want that!

I need:

K1 L1 L3 0.9
K2 L2 L3 0.8

Has anyone tried something like this? Linear tech support is looking into it and they dont seem to care much.

 

Did you try also defining K3 L1 L2? It seems like this would be necessary in this case.

 

Yes I've tried.

The situation is this:

2 seperate transformers (i.e. two different circuits same schematic) They need to be in same circuit because there is other connectivity but not magnetic.

Transformer #1 consists of L1 (pri) and L2 (sec)
Transformer #2 consists of L3 (pri) and L4 (sec)

Simply using K1 L1 L2 1 and K2 L3 L4 1, does not work. L3, L4 coupling ignored. I've gone as far as specifying all possible coupling (mutual only)
K1 L1 L2 1.
K2 L3 L4 1.
K3 L1 L3 0.
K4 L1 L4 0.
K5 L2 L3 0.
K6 L2 L4 0.
and even this doesnt work.
Its as if only one coupled pair is allowed per schematic..

Any ideas? Have you played around with it?

Thanks!

 

I haven't played with that situation. I was running a sim a couple of months ago with 3 coupled inductors having different mutual couplings, and it seemed to work OK. I'll play with this if I get a chance.

 

I tried the schematic below. I've included the waves. It worked for me. Are you doing something different? Are you sure you did all your K's as .op's?

Attached Images

	coupling_sch.gif (5.0 KB, 145 views)
	coupling_waves.gif (6.9 KB, 144 views)

 

Ron, ok thanks for checking...

I guess there is nothing wrong.
The same circuit works here at home but does not at work!
I really don't know whats going on with that version but when
I load the .asc file I tried at work, the coupling works just fine..
I think I'll upgrade it to the latest version...
:roll: