Dual programmable response time constants for electronic tap switching line regulators

摘要

A dual programmable control time constant circuit is provided for a tap switching line voltage regulator of the type which selectively switches in a sequential adjacent one of a predetermined number of taps on a winding of a transformer. The dual programmable control time constant circuit includes a stepping counter and a first bistable device for determining how long a sensed signal representative of the voltage of the load circuit may be permitted to remain outside preset upper and lower limits before corrective action is taken. A second bistable device is used to reset the stepping counter when the sensed signal has changed so as to again fall within the preset limits for a predetermined time. The dual programmable control time constants provide for large variations in load characteristics with the minimum time required per tap change consistent with stable regulator operation. The surge current caused by excessive tap switching is reduced to prevent damage to the regulator and load components.