Trouble with Tappings

Increasing the number of effective turns on the HV side will decrease the voltage on the LV side, and vice versa.

Sir,

Thank you for your reply, I can understand the concept. But I have studied in a

book that , " in a step down transformer to get a output voltage up to 10% above

nominal voltage with nominal voltage applied to high voltage winding , and allow for 5%

regulation in transformer require that tapping should be on H.V side at about -13%. Thus

the voltage in L.V side will be boosted by 15%."

I cannot understand this, Can you please explain this ?

100%/(100%-13%) = 115%

Sir,

Thank you for your reply, my doubt is if -13% tapping is provided means the voltage on H.V side is reduced by 13%, then how the voltage on L.V side will be boosted. Can you please explain this.

The voltage applied to the primary side remains the same. The number of primary turns goes down by 13%. Therefore the secondary voltage goes up by 15%.

Tapping? Do you mean Amanda Tapping?

I've no doubts about her at all!