Adapted from CIM data models. The class represents IEEE Std 421.5-2005 type AC3A model. The model represents the field-controlled alternator-rectifier excitation systems designated Type AC3A. These excitation systems include an alternator main exciter with non-controlled rectifiers. The exciter employs self-excitation, and the voltage regulator power is derived from the exciter output voltage. Therefore, this system has an additional nonlinearity, simulated by the use of a multiplier whose inputs are the voltage regulator command signal, , and the exciter output voltage, , times . This model is applicable to excitation systems employing static voltage regulators. Reference: IEEE Standard 421.5-2005 Section 6.3.