Complex sentence: The transformer consists of two ring-like windings, and the secondary circuit has a large air space between the winding and the magnetic core to provide both isolation from high voltage and low inter-winding coupling capacitance.
Split into simpler sentences: The transformer consists of two ring-like windings with a large air space between the winding and the magnetic core. The large spacing provides both isolation from high voltage and low inter-winding coupling capacitance.