Understanding a magnetic exciter-regulator for a slip-ring AC generator.

Thread Starter

Just Another Sparky

Joined Dec 8, 2019
Hey there. I've been working on a beautiful old 5kVA generator set in my spare time. One of the items on my to-do list is to re-mount the magnetic-type voltage regulator after years of exposure to vibration sheared it's mounting screws off.

I would like to get a better understanding of how and why this type of transformer works. I've never heard of or seen this type of arrangement before. Would anyone care to help me understand it's principle of operation? I've traced out the complete circuit and taken a photo of it for reference.

In case it's not clear, the second part number on the transformer reads '883048'.

From general observation I would assume that T1-L1 and T4-L2 are current windings. T1-S2 is obviously a secondary winding. Perhaps they are all current windings, where the transformer essentially couples a portion of the sum of T1-L1 and T4-L2 through the exciter windings? In that case, R1 would be the primary determinant of the no-load voltage by setting the base rotor current and the transformer would simply add extra rotor current as the stator current increases.

Am I on the right track?
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