Noise of electric bikes

Summary of e-NVH sound sample
ApplicationScott® “syncros” moutain e-bike, Scott® “e-sub” urban e-bike, Wayscral® urban e-bike
Electrical machineUnknown
Supply conditionRun-up at max torque
Noise sourcesElectromagnetic, mechanical
See also 

Measurement set-up

Noise is measured 40 cm away from the electric powertrain, on the electric bikes. A run-up is done up to 20 km/h with different electric power modes.
The following electric bikes are tested:

Moutain e-bike
Moutain e-bike
Hybrid e-bicycle
Hybrid e-bicycle

Sound file and spectrograms

Sound of electric powertrain of Scott® “syncros” moutain e-bike

Sound of electric powertrain of Scott® “e-sub” urban e-bike

Sound of electric powertrain of Wayscral® urban e-bike

Note: these sound files are the property of EOMYS; for authorized use in presentations, website, publications or technical work, please contact us

E-NVH interpretations

These sound files illustrate electromagnetically-excited noise due to the electric traction motor of different electrically-assisted bikes. Besides low frequency gravel noise due to tyre/road interaction, one can clearly hear the whine noise of the electric motor coming from Maxwell force harmonics. A second potential source of electromagnetic noise comes from PWM effects but the switching frequency of tested e-bikes is too high (18 kHz) to be heard by the driver.

Application to MANATEE

MANATEE software can be used to quickly calculate NVH due to electromagnetic forces both in early design and detailed design phase, including PWM and slotting effects.