Can we get speeds above rated speed by armature resistance control method?

Yes, speeds above the rated speed can be achieved using the armature resistance control method in DC motors. By increasing the armature resistance, the voltage drop across the resistance can be manipulated, allowing for higher speeds. However, this approach is limited and can lead to inefficiencies, overheating, and reduced torque at higher speeds. Therefore, while it is possible, it is generally not the most efficient or practical method for achieving high speeds.