The transition impedance in form of a resistor or reactor consists of one or more
units that are bridging adjacent taps for transferring load from one tap to the
other without interruption or appreciable change in the load current.Normally, reactor type OLTCs use the bridging position as a service
position and, therefore, the reactor is designed for continuous loading. Depending on the various winding arrangements and OLTCdesigns,
separate selector switches and changeover selectors (reversing or
coarse type) are used in additionThe main components
of an OLTC are contact systems for make and break currents as well as carrying
currents, transition impedances, gearings, spring energy accumulators and a
drive mechanism.