Electric motor, fan, and system including an electric motor and an evaluation unit

An electric motor comprising:

• at least one bearing;
• an axle or shaft rotatably mounted to the least one bearing;
• a sound chamber located within the electric motor and delimited by a plurality of boundary surfaces;
• a circuit board disposed within the electric motor and having motor electronics, wherein the circuit board forms one of the plurality of boundary surfaces and wherein the sound chamber is disposed between the circuit board and a stator bushing of the electric motor;
• a sound sensor located on the circuit board within the sound chamber, wherein sound is generated during operation of the electric motor, the sound being detectable by the sound sensor, wherein at least one boundary surface comprises an acoustic surface, the acoustic surface comprising a surface of the at least one bearing or a surface of a body conducting sound to the at least one boundary surface, the sound sensor being configured to detect sound transmitted through air from the acoustic surface to the sound sensor.