The components of a hub motor typically include a stator, rotor, bearings, motor controller and others. The stator contains the coils, while the rotor holds the permanent magnets. The bearings enable smooth rotation, and the housing provides protection and support for the motor.
The stator is the stationary core component of the hub motor. It consists of wound copper wire coils wrapped around an iron core structure in a precise arrangement. When electrical current flows through the coils, it generates an electromagnetic field due to the properties of electricity and magnetism.
The electromagnetic field is generated through the coils in a specific pattern or phases determined by the controller's input. There are typically three phases that produce rotating magnetic vectors when powered sequentially. The stator's electromagnetic field provides the pulling and rotational force on the rotor component.
Attached directly to the wheel hub, the rotor component rotates along with wheel motion. It features a set of powerful rare-earth magnets arranged in a circular manner around its outer rim. When placed inside the stator's electromagnetic field, the rotor magnets are pulled and pushed accordingly, causing the rotor to spin.
As the rotor magnets pass each coil winding during rotation, the poles are alternately attracted and repelled, driving continuous 360-degree motion. The rotor transfers this rotational torque directly through bearing contact points to spin the wheel forward for propulsion. Without the stator's electromagnetism acting upon it, the rotor would remain stationary.
High-quality ball or sleeve bearings contained within the motor housing allow the rotor to freely rotate with minimal friction or resistance. Proper bearing lubrication and sealing is vital to preventing wear down. Even microscopic bearing damage could cause increased drag and heat along with eccentric or wobbly rotation over time.
Manufacturers often use durable metal or ceramic hybrid bearings for long-lasting, smooth operation in hub motors operating at high speeds. Bearing maintenance and inspection is important for avoiding eventual failure that would require motor replacement.
The motor controller is the electronic "brain" that regulates motor function. It converts battery voltage to three-phase AC waveforms supplied to the individual stator coil windings. By varying frequency, voltage amplitude, and winding sequence, the controller modulates rotational torque and speed output.
Sensors provide controller feedback on motor status. On e-bikes, twisting the throttle sends a voltage signal instructing the controller to increase assistance as needed for inclines or higher speeds. Controllers also enable dynamic and regenerative braking for safety and energy recapture. Sophisticated programming optimizes motor efficiency.
timizes motor efficiency.
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