Inductance is proportional to turns squared, not square root. Start with a simpler winding with one tap, and look at the directions of current flow. In an autotransformer, the 'secondary' current opposes the 'primary' current.

The following items have been added to the Files area of the LTspice@groups.io group.

• /Temp/Autotransformer.zip

By: Bell, Dave <Dave.Bell@...>

Description:
I need some tutorials regarding autotransformer modelling! I was intrigued by Hassan's AC Stabilizer and tried to model TR1 The model differed from my expectations in several ways. 1: Why do the tap-to-tap voltages differ? 2: Why is the separate 18V winding so different? 2a: Why is it more different when I separate the Kxxx directives? 3: Why do the outputs throw infinities with megohm loads, but not when open??

-- 
OOO - Own Opinions Only
Best Wishes
John Woodgate
Keep trying

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