(Solved): In the wound-rotor motor lab video, why wouldn't the rotor turn when the rotor circuit was left ope ...

In the wound-rotor motor lab video, why wouldn't the rotor turn when the rotor circuit was left open with no electrical connections? Because in this case, the rotor would be nearly dead-shorted, similar to a squirrel cage induction motor's rotor. Because then there could be no rotating magnetic field in the stator. Because then the stator connection would lose a phase. Because no current flow can occur in the rotor if the rotor circuit is not connected.