LTSpice multiwinding transformer

I'm trying to model a six-winding transformer - three sets of centre-tapped coils, one pair with 0.25mH of inductance in each col, the next with 22.5uH and the last with 2.5uH. Coil coupling is set by

K1 L1 L2 L3 L4 L5 L6 0.99

With four winding everything seems to work, but with six, neither pair of secondaries shows any induced voltage.

Is this a known bug?

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Bill Sloman, Nijmegen
Reply to
Bill Sloman
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I don't know if it is a bug, but you could try substituting the alternate and equivalent expression, listing the 15 mutual inductances separately:

K12 L1 L2 0.99 K13 L1 L3 0.99 K14 L1 L4 0.99 K15 L1 L5 0.99 K16 L1 L6 0.99 K23 L2 L3 0.99 K24 L2 L4 0.99 K25 L2 L5 0.99 K26 L2 L6 0.99 K34 L3 L4 0.99 K35 L3 L5 0.99 K36 L3 L6 0.99 K45 L4 L5 0.99 K46 L4 L6 0.99 K56 L5 L6 0.99

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Ned Forrester        n_f_orrester@whoi.edu         508-289-2226
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Reply to
Ned Forrester

"Bill Sloman" schrieb im Newsbeitrag news:4a2da0aa$0$1639$ snipped-for-privacy@textnews.kpn.nl...

Hello Bill,

I wonder what you did. It works like promised. I have attached a working example with exactly your values.

You can send me your circuit for a check, if you can't find the mistake in your circuit.

Best regards, Helmut

Version 4 SHEET 1 880 680 WIRE -32 64 -112 64 WIRE 112 64 48 64 WIRE -112 80 -112 64 WIRE 112 96 112 64 WIRE 272 96 272 64 WIRE 432 96 432 64 WIRE -112 192 -112 160 WIRE 112 192 112 176 WIRE 112 192 -112 192 WIRE 272 192 272 176 WIRE 272 192 112 192 WIRE 432 192 432 176 WIRE 432 192 272 192 WIRE -112 208 -112 192 WIRE 112 208 112 192 WIRE 272 208 272 192 WIRE 432 208 432 192 WIRE 112 320 112 288 WIRE 272 320 272 288 WIRE 432 320 432 288 FLAG -112 208 0 SYMBOL ind2 96 80 R0 SYMATTR InstName L1 SYMATTR Value 250µ SYMATTR Type ind SYMBOL ind2 96 192 R0 SYMATTR InstName L2 SYMATTR Value 250µ SYMATTR Type ind SYMBOL ind2 256 80 R0 SYMATTR InstName L3 SYMATTR Value 25µ SYMATTR Type ind SYMBOL ind2 256 192 R0 SYMATTR InstName L4 SYMATTR Value 25µ SYMATTR Type ind SYMBOL ind2 416 80 R0 SYMATTR InstName L5 SYMATTR Value 2.5µ SYMATTR Type ind SYMBOL ind2 416 192 R0 SYMATTR InstName L6 SYMATTR Value 2.5µ SYMATTR Type ind SYMBOL voltage -112 64 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V1 SYMATTR Value SINE(0 10 20k) SYMBOL res -48 80 R270 WINDOW 0 32 56 VTop 0 WINDOW 3 0 56 VBottom 0 SYMATTR InstName R1 SYMATTR Value 1 TEXT -120 -24 Left 0 !.tran 1m TEXT 32 -24 Left 0 !K1 L1 L2 L3 L4 L5 L6 0.99

Reply to
Helmut Sennewald

"Helmut Sennewald" schreef in bericht news:h0m9qr$ott$02$ snipped-for-privacy@news.t-online.com...

Your circuit runs exactly as it should on my computer.

When I compared .asc files, the only difference I could see was that you'd used 25µ where I'd typed 0.000025, but switching didn't make any difference.

I've got your 2003 e-mail address and I'll send you my .asc file; it's too long to post here and since I hope to be able to publish it in a scholarly journal eventually, I don't really want to post it to an open forum.

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Bill Sloman, Nijmegen
Reply to
Bill Sloman

Thanks for the suggestion. In fact I'd originally listed all fifteen mutual inductances, and only found - and tried - the more compact expression after I'd been reduced to RTFM.

I'm obviously doing something stupid - because Helmut's test circuit works fine - but I can't for the life of me see what it might be. I hope Helmut can find something. in my .asc file.

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Bill Sloman, Nijmegen
Reply to
Bill Sloman

"Bill Sloman" schreef in bericht news:4a2da0aa$0$1639$ snipped-for-privacy@textnews.kpn.nl...

The bug was pure stupidity on my part - I typed in the Spice directive as text (in blue) rather than as a Spice directive (which would have shown up as black type) .

Helmut Sennewald very generously found the fault in my .asc file, and I'm appropriately grateful.

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Bill Sloman, Nijmegen
Reply to
Bill Sloman

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