Which of the following is a possible cause for a motor to overheat?

A motor can overheat due to several potential factors, all of which contribute to its operating efficiency and thermal management. Improper lubrication, for instance, can lead to increased friction between moving parts, generating excess heat within the motor. Without adequate lubrication, components wear down more quickly, exacerbating heat buildup.

High ambient temperature is another critical factor. When the surrounding environment is excessively hot, the motor has to work harder to dissipate heat. This can overwhelm its cooling capabilities and result in a higher operating temperature.

Insufficient voltage supply can also be a reason for overheating. When a motor is not receiving the proper voltage, it may draw more current to compensate, leading to increased power dissipation as heat. This not only affects the motor's efficiency but also its ability to function without overheating.

Since each of these causes can individually contribute to overheating, the accumulation of all these factors reinforces the rationale for selecting the option that encompasses all possibilities. Understanding the interrelated nature of these issues can help in diagnosing and preventing motor overheating in practical applications.