What will happen if the armature rheostat is zero and field circuit resistance is kept high in a dc motor?

If the armature rheostat is set to zero and the field circuit resistance is kept high in a DC motor, the armature will receive maximum current, leading to a high armature current. However, with a high field circuit resistance, the field current will be low, resulting in a weak magnetic field. This imbalance can cause the motor to run at a very high speed, potentially leading to instability or damage due to excessive armature current and insufficient torque production. Overall, the motor may operate inefficiently and could risk mechanical failure.