EC Motor Noise Control
Fan EC Motor Permanent Magnet Synchronous Motor Selection Focus Part 10 -EC Motor Noise Control
It is very important to control the noise of fan EC motor in actual operation, especially for fans with close contact with animals such as HVAC system, animal husbandry fan, etc. It is directly related to users' evaluation of fan performance. Of course, the noise control of the fan is actually mainly the design and optimization of the fan structure and blades. We mainly explain what role the EC motor can play in the noise control of the fan.
1. Mechanical noise
Motor rotor rotation imbalance, bearing, casing, end cover concentricity, installation progress error;
When the motor rotates, the bearing also rotates, and the rolling bearing of the motor is one of the main noise sources of the machine. The manufacturing error, installation error and bearing wear of the motor make the motor resonate and produce noise. Installation progress or bearing wear makes the rotor eccentric, which causes unilateral magnetic pull force, increases bearing radial pressure, and causes stator-rotor friction to generate new mechanical noise.
2. Electromagnetic noise
Stator coil excitation electromagnetic noise, current harmonics and other factors;
Permanent magnet synchronous motors need stator coil excitation for operation, and manufacturers choose different air gap coordination according to experience and technical realization capability. The radial force wave of air gap magnetic field and the radial deformation of rotor produce periodic oscillation, causing electromagnetic noise. At present, most permanent magnet motors are DC brushless motors, and the current waveform output by DC brushless controllers is trapezoidal current waveform instead of sine wave. There are a large number of current harmonics, which will amplify the electromagnetic noise of permanent magnet motors (harmonic current or harmonic voltage is not considered to generate additional losses in stator windings and iron cores, thus reducing the efficiency of power usage. )
To sum up, fan EC motor noise control is not only related to fan noise interference to fan user environment, but also related to fan EC motor performance and stability. Fan manufacturers should comprehensively consider the professional level of suppliers in the field of permanent magnet synchronous motor and controller technology when selecting fan EC motor/fan permanent magnet synchronous motor, so as to avoid detours of enterprise high-performance fans due to wrong selection.