To achieve the buck/Enhance function, all that is necessary is 2 independent switches so which the AC input can be linked to one of the two Major taps, while the load is connected to one other, So utilizing the key transformer's Main windings being an autotransformer. Uninterruptible power supply (UPS) https://trenton49247.livebloggs.com/40172409/the-2-minute-rule-for-uninterruptible-power-supply-pronunciation