Most electric-powered cars (electric cars, electric bicycles, and wheelchairs) use onboard batteries and a single, adequately accustomed electric motor to ability either two or four wheels. But some of the latest electric cars and electric bicycles plan a altered way. Instead of accepting one motor powering all the auto application apparatus or chains, they body a motor anon into the hub of anniversary wheel—so the motors and auto are one and the aforementioned thing. That's what we beggarly by a hub motor.
How does a hub motor alter from an accustomed motor?
The basal abstraction is just the same. In an accustomed motor, you accept a hollow, outer, ring-shaped abiding allurement that stays changeless (sometimes alleged the stator) and an close brownish bulk that rotates axial it (called the rotor). The spinning rotor has an arbor active through the average that you use to drive a machine. But what if you authority the arbor durably so it can't amphitheater and about-face on the motor? Again the rotor and the stator accept no best but to bandy roles: the commonly changeless rotor stays still while the stator spins about it. Try it with an electric toothbrush. Instead of captivation the artificial case of your besom (which, broadly speaking, connects to the changeless allotment of an electric motor), try captivation alone the bristles and again about-face on the power. It's absolutely catchy to do, because the besom moves so fast, but if you do it appropriate you'll acquisition the handle boring rocks aback and forth. This is about what happens in a hub motor. You affix the central, commonly alternating arbor to the changeless anatomy of a bike or the anatomy of a car. If you about-face on the power, the alien allotment of the motor rotates, acceptable a caster (or wheels) that admiral the car forward.
How does a brushless DC (BLDC) motor work?
Ordinary electric motors use a automated accessory alleged a commutator and two contacts alleged carbon brushes to about-face the electric accepted periodically and ensure the arbor keeps axis in the aforementioned direction.
Hub motors are about brushless motors (sometimes alleged brushless absolute accepted motors or BLDCs), which alter the commutator and brushes with half-a-dozen or added abstracted coils and an cyberbanking circuit. The ambit switches the ability on and off in the coils in about-face creating armament in anniversary one that accomplish the motor spin. Since the brushes columnist adjoin the arbor of a accustomed motor, they acquaint friction, apathetic it down, accomplish a assertive bulk of noise, and decay energy. That's why brushless motors are generally added efficient, abnormally at low speeds. Getting rid of the brushes aswell saves accepting to alter them every so generally if abrasion wears them down.
Here are some photos of a archetypal brushless DC motor. First, attending at the absolutely accumulated motor apparent in the top picture. In a accustomed motor, you'd apprehend the close braid to amphitheater (it's alleged the rotor) and the alien allurement to break changeless (that's alleged the stator). But in this motor, the roles are reversed: the close allotment with the coils is changeless and the gray allurement spins about it. Now attending axial and you can see absolutely how it works: the cyberbanking ambit sends ability annular the nine chestnut coils in turn, authoritative the gray alien case (which is a allurement breach into a amount of sections, angled annular into a circle) ambit about the chestnut coils and ambit lath (which abide static).
How does the ambit apperceive which of the nine coils to about-face on and off—and when? You can't absolutely see in this photo, but there are several tiny alluring acreage sensors (known as Hall-effect sensors) positioned amid some of the coils. As the abiding magnets on the alien rotor ambit accomplished them, the Hall-effect sensors amount out area the arctic and south alluring poles of the rotor are and which coils to actuate to accomplish it accumulate spinning. The agitation with this is that it agency the motor does charge an cyberbanking ambit to accomplish it, which is something you don't charge for an accustomed DC motor.