If Pmax is the maximum power that can be supplied by a cylindrical rotor synchronous machine, state whether the load can be suddenly raised to 0.9 Pmax without destabilising the machine when it is supplying 0.5Pmax . If it is not possible what is the minimum value of the initial load so that increase of load to 0.9 Pmax will not destabilise the machine. Apply equal area criterion neglecting damping andarmature resistance.