What is the major disadvantage of running a motor on low voltage?

Running a motor on low voltage can significantly reduce its ability to produce torque, which is essential for driving loads effectively. Motors are designed to operate within a specific voltage range to maintain optimal performance. When the applied voltage is lower than what the motor is rated for, the current drawn by the motor increases as it attempts to compensate for the insufficient voltage. This increase in current can lead to overheating, as the motor operates harder to generate the necessary torque.

This condition can cause stress on the motor's components, potentially resulting in premature failure. The overheating not only affects the efficiency but can also damage insulation and other critical parts of the motor, leading to further complications down the line. Therefore, the major disadvantage of operating a motor on low voltage is the decrease in torque coupled with the risk of overheating, which can compromise the motor's longevity and reliability.

In contrast, the other options presented do not directly relate to the primary implications of low-voltage operation. While increased energy consumption and higher operational noise may occur under certain conditions, they are not the direct and immediate consequences associated with low voltage. Increased mechanical wear can result from prolonged operation under detrimental conditions, but it is the reduced torque and overheating that are specifically tied to low voltage scenarios.