What can be a common outcome of using a malfunctioning feeding system in a DC machine?

Using a malfunctioning feeding system in a DC machine can lead to overheating. This happens because an improper feeding system may result in insufficient or erratic supply of current to the winding or armature, which can cause the machine to draw more power than necessary, leading to excessive heat generation. Overheating can also occur if there is an overload on the machine due to inadequate feed, causing the motor to work harder and generate heat without being able to dissipate it effectively.

In contrast, increased efficiency is unlikely as inefficiencies would arise from malfunction, while improved speed control would not be a result of a malfunctioning system, as control typically relies on a properly functioning feeding system. Equal torque output would also be compromised, as inconsistent current would affect the torque produced by the motor, and thus it may vary rather than remain equal.