"抽头转换开关" can be translated as "tap-changer switch" or simply "tap changer" (when the context clearly refers to the switching device).
Tap-changer switch emphasizes the switching function of the device.
Tap changer is a more concise term commonly used in electrical engineering contexts to refer to the entire mechanism (including the switch and related controls) for changing taps on a transformer.
Both are acceptable, with "tap changer" being more prevalent in technical discussions.