Induction Regulator

An induction regulator is essentially a constant voltage transformer, one winding of which can be moved  w.r.t. the other, thereby obtaining a variable secondary voltage. The primary winding is connected across the supply while the secondary winding is connected in series with the line whose voltage is to be controlled. When the position of one winding is changed w.r.t. the other, the secondary voltage injected into the line also changes. There are two types of induction regulators viz. single phase and 3-phase.

 

 

A single phase induction regulator is illustrated in Fig. 4. In construction, it is similar to a single phase induction motor except that the rotor is not allowed to rotate continuously but can be adjusted in any position either manually or by a small motor. The primary winding  AB is wound on the  stator and is connected across the supply line. The secondary winding  CD is wound on the rotor and is connected in series with the line whose voltage is to be controlled. The primary exciting current produces an alternating flux that induces an alternating voltage in the secondary winding  CD . The magnitude of voltage induced in the secondary depends upon its position w.r.t. the primary winding. By adjusting the rotor to a suitable position, the secondary voltage can be varied from a maximum positive to a maximum negative value. In this way, the regulator can add or subtract from the circuit voltage according to the relative positions of the two windings. Owing to their greater flexibility, single phase regulators are frequently used for voltage control of distribution primary feeders.