Question 6A334

When starting a DC motor, minimizing resistance in the motor-field circuit is crucial. This establishes maximum field current, creating the strongest possible magnetic field. A strong field ensures that as the motor's armature begins to turn, a high back electromotive force (EMF) is quickly generated. This back EMF directly opposes the applied voltage, effectively limiting the dangerously high inrush current that would otherwise flow through the low-resistance armature windings at startup. Excessive starting current can overheat and severely damage the motor. Conversely, maximum resistance in the field circuit would result in a weak field, low back EMF, and an unacceptably high starting current.