I tried simulating a simple synchronous generator driving a resistive load in isolated mode (not connected to the grid/infinite bus), using Matlab Simulink, SimPowerSystems. First I used, Input mechanical power of 1 pu, and output resistive Load of 1 Pu. And Excitation Field Voltage of 4 pu. This resulted on output terminal Voltage of 1 pu, Output Electrical Power of 1 pu, and, and Rotor Speed of around 0.5 pu. I then Increased the excitation voltage to around 6 pu and everything remaining same, the rotor speed drooped to 0.3 pu. All this seems logical, in that, when I am over exciting, this result in higher Pole fields. In order to maintain same terminal voltage, the rotor speed must decrease. Same terminal voltage needs to be maintained, because, since the load I used was resistive load, only by maintaining fixed terminal voltage, can the electrical output power equal the fixed input mechanical power. As we know, the two powers (input mechanical power and output electrical power) must always equal, their difference creates an accelerating torque that restores the rotor to correct speed. I hope everything I said is correct? I will ask my question once I get the confirmation that I was correct. Thanks.