How to analyse the sound of Motor

1. What makes a motor sound?
2. What makes an electric motor sound?
3. Why are electric motors quiet?

What makes a motor sound?

Mechanical noise. The sources of mechanical noise in a motor include a loose stator core; worn, damaged or poorly lubricated bearings; and rubbing of internal components. Additionally, any structural part of the motor that is excited at its natural frequency can become the source of airborne noise.

What makes an electric motor sound?

Mechanical forces within a motor can cause magnetic noise. This is the result of pressure generated by magnetized parts. Some of the common types of magnetic noise in an electric motor include unequal air gap, slip noise, and skewing.

Why are electric motors quiet?

Induction motors run only on AC power and do not use brushes -- that is the main reason they are so quiet.