Electrical analogue of a 2-stage Rototrol

THE HIGH-CAPACITY 2-stage Rototrol shows great promise as the principal element in large generator excitation systems. Figure 1 illustrates a voltage-regulating system. The main unit is a 70,000-kva 3,600-rpm turbo-generator. The excitation is supplied by a 200-kw 2-stage Rototrol. The static network consists of a saturating reactor, the impedance of which is compared automatically with a capacitive reactance of constant value. As the generator voltage increases, the reactance of the saturating reactor decreases until at the regulated voltage, the reactances of both elements are equal. In this manner, a reference point is obtained. The output of the static network is rectified by dry-type rectifiers and introduced into the control field of the Rototrol.