In alt.engineering.electrical Michael Moroney wrote:

| Are the load tap generators configured make-before-break?
| Break-before-make would mean a (very short) power outage every activation
| but make-before-break would mean a momentarily short-circuited winding and
| the break would involve interrupting a large short circuit current.

I wonder how much regulation could be managed through the use of variable
leakage inductance in the transformer windings.


| Certainly modern ones likely use thyristors and zero crossing detectors.

With zero crossing detection, then the switching is not happening on all phases
at the same time.

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writes:

In alt.engineering.electrical Michael Moroney wrote:

| Are the load tap generators configured make-before-break?
| Break-before-make would mean a (very short) power outage every activation
| but make-before-break would mean a momentarily short-circuited winding and
| the break would involve interrupting a large short circuit current.

I wonder how much regulation could be managed through the use of variable
leakage inductance in the transformer windings.

Good question.

| Certainly modern ones likely use thyristors and zero crossing detectors.

With zero crossing detection, then the switching is not happening on all phases
at the same time.

Since the ones I've seen are 3 (or 2) independent autotransformers, this
is true without zero crossing detectors, and the power supplied may not
always be of equal voltages 120 degrees apart.