Motor noise can affect much more than just the acoustic environment; they can also reveal design or manufacturer defects. Motor noise control is an important aspect of performance for noise-sensitive applications like medical equipment, household appliances, electric powered passenger vehicles, and sanitation vehicles.
The expected common sources of noise from motors are:
Electromagnetic noise: Is generated in small amounts when there are periodic changes in magnetic forces, and where variations in the air gap or imbalances in the magnetic fields are present; period tonal operations can produce whining sounds or vibrations.
Mechanical noise: Typically emanates from bearing tolerances, or imbalance in the rotor, or during misalignments during assembly, often more prevalent in larger size motors or faster speed motors.
Aerodynamic noise: Is a component of air cooled motors, the air stream is disrupted by fan blades.
Electrical switching noise: Audible frequency noise can occur in brush motors, or in systems operating as an inverter, that switching can typically be high pitched tones or mixtures of audible frequencies.
The methods we can apply to control the above noises are typically:
Structural Design Optimisation: This may include but is not limited to different slot shape, slot fill-factor improvements, and balancing tooth combinations of the stator-rotor combinations, for the purpose of reducing higher harmonics of the electromagnetic forces.
Machined and Balanced Rotor: Machining will allow for concentric rotors and minimizing bearing edge clearance tolerances will contribute to mechanical vibration, which may include testing through dynamic modelling.
Low nuisance noise bearings and elastic mounts that minimize shock transmission and has smaller path lengths for noise transmission.
PWM Modulation frequency tuning: when motors are equipped with inverter systems it may be possible to slip audible sized noise frequencies into the noise frequency ranges that are away from sensitivity ranges, away from human perception.
In higher end applications, for example, when an electric passenger vehicle motor is not only to be imposed to a NVH (Noise, Vibration and Harshness) quality standard, the expectation from the customer is that the power train will operate below 60 dB since stationary and during the whole range of speeds during its performance cycle. Good quality and attention to detail will be required during the power train material selection, machining tolerances, and electronic control techniques for example.
As a company we have a long history of low noise motor design for both industrial and commercial applications. We can respond to our customers in terms of specialized designs for silent operation that have acoustic specifications, to improving products quality to the end user without polluting their experience with unexpected noise annoyance.
Motor noise can affect much more than just the acoustic environment; they can also reveal design or manufacturer defects. Motor noise control is an important aspect of performance for noise-sensitive applications like medical equipment, household appliances, electric powered passenger vehicles, and sanitation vehicles.
The expected common sources of noise from motors are:
Electromagnetic noise: Is generated in small amounts when there are periodic changes in magnetic forces, and where variations in the air gap or imbalances in the magnetic fields are present; period tonal operations can produce whining sounds or vibrations.
Mechanical noise: Typically emanates from bearing tolerances, or imbalance in the rotor, or during misalignments during assembly, often more prevalent in larger size motors or faster speed motors.
Aerodynamic noise: Is a component of air cooled motors, the air stream is disrupted by fan blades.
Electrical switching noise: Audible frequency noise can occur in brush motors, or in systems operating as an inverter, that switching can typically be high pitched tones or mixtures of audible frequencies.
The methods we can apply to control the above noises are typically:
Structural Design Optimisation: This may include but is not limited to different slot shape, slot fill-factor improvements, and balancing tooth combinations of the stator-rotor combinations, for the purpose of reducing higher harmonics of the electromagnetic forces.
Machined and Balanced Rotor: Machining will allow for concentric rotors and minimizing bearing edge clearance tolerances will contribute to mechanical vibration, which may include testing through dynamic modelling.
Low nuisance noise bearings and elastic mounts that minimize shock transmission and has smaller path lengths for noise transmission.
PWM Modulation frequency tuning: when motors are equipped with inverter systems it may be possible to slip audible sized noise frequencies into the noise frequency ranges that are away from sensitivity ranges, away from human perception.
In higher end applications, for example, when an electric passenger vehicle motor is not only to be imposed to a NVH (Noise, Vibration and Harshness) quality standard, the expectation from the customer is that the power train will operate below 60 dB since stationary and during the whole range of speeds during its performance cycle. Good quality and attention to detail will be required during the power train material selection, machining tolerances, and electronic control techniques for example.
As a company we have a long history of low noise motor design for both industrial and commercial applications. We can respond to our customers in terms of specialized designs for silent operation that have acoustic specifications, to improving products quality to the end user without polluting their experience with unexpected noise annoyance.
