The maximum power developed in a cylindrical synchronous machine depends on the
The maximum power developed in a cylindrical synchronous machine depends on both the synchronous reactance and excitation.
The synchronous reactance (Xs) is an inherent property of the synchronous machine that depends on the machine's physical dimensions and the magnetic properties of its materials.
The synchronous reactance determines the magnitude of the internal voltage generated in the machine and the magnitude of the armature current that flows through the machine when it is loaded.
The excitation (field current) controls the strength of the magnetic field in the rotor, which in turn controls the magnitude of the internal voltage generated in the machine.
The excitation can be adjusted to control the machine's output voltage and reactive power output, and it also affects the machine's ability to deliver active power to the load.
The load angle also affects the power output of the machine, but it does not directly determine the maximum power that can be developed.
The load angle is the angle difference between the stator voltage and the rotor voltage phasors, and it determines the active power output of the machine for a given excitation and synchronous reactance.
However, the maximum power that can be developed depends on the excitation and synchronous reactance.