How do you find the rotor voltage?

To find the rotor voltage in an induction motor, you can use the formula ( V_r = \frac{S \cdot V_s}{\sqrt{3}} ), where ( V_s ) is the stator voltage and ( S ) is the slip of the motor, calculated as ( S = \frac{N_s - N_r}{N_s} ), with ( N_s ) being the synchronous speed and ( N_r ) the rotor speed. It's important to remember that rotor voltage is typically induced and varies with the rotor's speed. Additionally, rotor voltage can be measured directly using appropriate instrumentation.