Which of the following is a common sign of motor overheating?

A common sign of motor overheating is indeed higher temperatures detected during inspection. Overheating in motors can occur due to various factors, including excessive load, inadequate cooling, or electrical issues such as phase imbalances or winding failures. During inspections, using a thermal imaging camera or a contact thermometer can help identify elevated temperatures, which is a clear indicator of overheating. Prolonged overheating can lead to damage in the motor’s windings, insulation breakdown, and ultimately motor failure, making temperature monitoring a vital part of routine maintenance.

In contrast, while increased noise levels from the motor may indicate mechanical issues or wear, it is not specifically linked to overheating. Decreased vibration levels could suggest the opposite, indicating a lack of mechanical movement or a more serious malfunction. Unusual color changes in the motor casing might imply overheating but may also relate to other issues, such as exposure to chemicals or aging, thus making it less definitive than simply measuring the temperature.