Tapcon 260 The voltage regulator serves to keep constant the output voltage of a transformer with an on-load tap-changer. To do this, the voltage regulator compares the transformer's measured output voltage (Vactual) with a defined reference voltage (Vreference). The difference between Vactual and Vdesired is the control deviation (dV). If the control deviation is greater than the specified bandwidth (B%), the voltage regulator emits a switching pulse after a defined delay time T1. The switching