You can adjust three bus parameters, terminal voltage, line current, and power factor. The power factor is adjustable, as it is the phase angle between the terminal voltage and the line current. You can also adjust two machine parameters, the armature resistance ) and the sum of synchronous reactance, and armature reactance ( + ). These values are multiplied by the line current to create the appropriate voltage drops. The synchronous impedance voltage drop is then represented by the black vector. This is the vector sum of the voltage drops due to armature resistance, synchronous reactance, and armature reactance. You can observe the power angle variation as the angle between the terminal voltage (green) and the generated voltage ) changes.