Central Point 3-phase Disc Type Tap Changer

Central point three-phase round off load tap changers are also employed in high voltage transformers in which the system includes a no load tap changer on the primary winding to accommodate system variations within a narrow band around the nominal rating. In such systems, the tap changer will often be set just once, at the time of installation, although it may be changed later during a scheduled outage to accommodate a long-term change in the system voltage profile.