Welcome to EOMYS e-NVH University ! You will find here a wide number of technical notes on magnetic noise and vibrations of electrical machines based on EOMYS Engineering consulting, testing, simulation and research experience. Interested to know more ? Check our training website for e-NVH courses.
Definition The theory of AC (Alternative Current) rotating machines considers sinusoidal supply currents, but in reality it is usually composed of an addition of multiple harmonics. For a given phase,
Definition The room equivalent absorption area, , is used to characterize the acoustic absorption capacity of a room. The acoustic absorption of a given room is linked to its wall
Impact on excitations Temperature can first influence electromagnetic excitations (e.g. slotting harmonics) responsible for magnetic noise in electric machines. It is already known that cogging torque varies with temperature due
Application to e-NVH The slot/pole combination and e-motor topology (induction machine Vs synchronous machine, radial Vs axial flux, internal Vs external rotor) determine the characteristic spectra of slotting magnetic forces
Definition The switching frequency and switching strategy determine the characteristic voltage and current supply spectra of AC electrical machines. They are chosen to maximize the converter output power, minimize electric
Context There are differences between sound parameters we measure physically and the sound perception we have as humans. For instance, we are used to describe the loudness of a sound
Definition Sound perception is a subjective phenomenon depending on both physical and cognitive factors. The aim of psychoacoustics is to better understand the human perception of sound and improve Sound
Definitions A tone is a sound composed of a single frequency component. Sounds we hear can be either pure tones (e.g. a whistle in a quiet background), or a combination
Context Hearing is a cognitive phenomenon : auditive perception can be improved with experience, but it can also diminish with age, hearing fatigue or traumatism. Perception varies from a person
Definition Some sounds may no longer be perceived when combined with an additional sound: this effect is called masking. There are two forms of masking : spectral and temporal. Spectral