How Does an Ebike Hub Motor Work?

The ebike hub motor works based on two inner parts. The outer shell and the inner core portion. The outer is like a rotating hub that surrounds the inner core portion. And the inner is usually a bunch of tightly and concaved wire which acts as a magnetic field.

The inner portion has again two portions, the stator and the rotor. And the basic operational matter of a hub motor is all about the rotation, and formation of a rotating magnetic field.

When the motor gets the electrical energy, the Hub Motors creates an Insider Magneto Electric Rotating Torque. This rotation happens with the help of the stator winding. And this magnetic field impacts the current force (of the electric conductor). Ultimately it causes to rotate the motor and finally to rotate the wheels.

What is Hub Motors? (Silly question! But need to know!):

Usually, an ebike hub motor is a rotating electric machine that converts electric energy to mechanical energy. This mechanical energy moves the wheels.

This motor consists of an Electromagnetic Winding plus an evenly distributed Stator Winding.  Both the Winding and the Stator cause to generate the working principle Magnetic field plus the rotating Armature(Rotor).

Hub motors are also one kind of E-Bike Motor, which needs to convert the electric power into motive power. This motor is prepared using a tightly coiled bunch of wires. And with the help of side magnet poles, this coil spin to make a force. This force generally turns the wheel and further drives the ebike.

What is Hub Motors

Electric bikes run using an onboard battery and a single but powerful electric motor. So why does the motor need on an electric bike? It needs to assist the pedaling, to speed faster, and to stop the manual pedaling. However, the electric motor uses on the ebike powers the two wheels and causes moves forward.

Unlike some other electric motor (powers all wheels through the chain or the gear), the e-bike hub motor is placed on the direct hub (of the wheel) and becomes the same as the wheel.

As the motor is placed directly on the hub of the motor, turning on your motor means turning on the wheel. So the wheels and the motor becomes the same. And that’s the meaning of a hub motor.

Types of Hub Motors:

For a better understanding of the ebike hub motor’s working mechanism, let me tell you about the types of Hub motors. Hub motors are of two types, Geared Hub Motor & Gearless Hub Motor.

The geared hub motor usually works using the Internal Planetary Gears (so that can reduce the Higher RPM motor’s speed). And the Gearless hub motors work by a direct connection of the lower RPM Motor Stator’s Axle to the electric bike.

How Does An Ebike Hub Motor Work?

Hub motors work the same as BLDC motors (Quadcopters, RC Electric Airplanes). This motor has two parts, an outer shell, and an inner portion. The outer of this motor is usually a rotating hub. And the inner portion of this motor is made using lots of concave magnets.

How Does An Ebike Hub Motor Work

This shell rotates at a fixed angle (with the help of bearings). The inner parts never spin, but it is placed on the axle. This portion has a tightly placed bunch of wire which faces the magnets. The 3 phases of this entire coil system intend to make a magnetic field (rotating).

So the permanent magnet field already placed in the system, try to align itself with the rotating magnetic field. Which in turn, moves the hub and forces the wheel to turn around.  So how do the 3 phases get the power?

The external power supply from the battery to the motor converts the electric power to the 3 phase AC motor power. And in turn, it works for further alignment. However, the 3 phase AC motor power works with variable frequency. To ensure synchronization of this variable frequency range (with the main motor’s speed) some hub motors may come with additional hall sensors. Finally, these motors can automatically work to feedback the update.

What Are The Advantages & Disadvantages Of The Ebike Hub Motor?

An electric bicycle is different from an electric car. If you add a hub motor to your electric bike-it will give you both the pros and cons. Hub motors with batteries become too heavy on the electric bike. Ultimately creates an unsprung weight on the bike wheel. Hub motors can snap the electric bike towards dropouts. This motor also forces you to feel sluggish for pedaling! Moreover, the tire change is also difficult in case the ebike has a hub motor.

The Advantage of Hub Motors is; it needs no (or little) maintenance. As the entire system in a hub motor is independent, controls the whole insider components by leaving no extra residue or mess within the total system.

As Wheel Hub Motor features perfect adaptability for compactness, also it features a high torque-therefore you can easily take it as a good alternative to any of the traditional electric motor for your dearest electric bike.

However, let’s come at the first cons of this motor, the extra heavyweight! The heavyweight sometimes could be an advantage for you. Suppose you are not feeling to manual pedaling, so this heavyweight can give you a pleasant and good riding experience by distributing the heavyweight more evenly on your ebike.

Hub Motor Vs. Mid-Drive; Which One Is More Preferable For You?

A hub motor offers a more natural feel to pedal with the help of its torque sensor. Though the average mid-drive bike has a few advantages over the hub-drive ebike, still it is so expensive, cannot afford by all bikers. The advantages of Hub Motors are fixed within two points-no internal energy loss plus cost shavings tendency.

Mid-drive motors are more efficient sometimes due to their high performance and good torque. These motors rotate the crank, instead of rotating the wheels. So in the existing bike’s gear, a mid-drive motor can multiply the power and produce a better advantage.

However, hub motors also have a few Inherent Efficiency Advantages. As inside of this motor, there is no mentionable intermediate phase (between the motor and the road; direct tire-road interface), therefore this total system faces almost no intermediary power losses.

Finally, the user can get an efficient motor running with almost no efficiency losses.

Get to Know Better: How Long Does an Electric Bike Motor Last?

So why a Hub Motor is different from an Ordinary Motor?

Though the basic idea is almost the same, the hub motor has some specialty. In an ordinary ebike motor, the stator (a hollow-like, ring-shaped, permanent magnet, static) is placed outer the rotor (inner metallic core).

This rotor works by spinning through the middle and driving the bike. The problem is that in this motor, the spinning rotor works through the axle in the middle direction to move the ebike.

But in the hub motor, the centrally rotating axle connects with the bicycle frame (static). Therefore, when you turn on the power, the outer parts of this hub motor rotate to power the ebike.

Final Verdict

Let’s pull the finishing today saying the future of the ebike hub motor. Ebike hub motor already makes a target project to reach the USD 12.5billion within 6 years (That is by 2028). (Adroit Market Research, 2020). Maybe now you can predict, why we are talking about an ebike hub motor or its working mechanism!

However, if you have a hub-ebike, or if you are intending to purchase a new one-understanding of the working principle of a hub motor is important for you. It will help you to bring you more closure with your ebike motor, ultimately to the heart of your ebike.

That’s all about –how does an ebike hub motor work.

Thanks.

Rudy Johnson

Rudy Johnson is the owner and main author of this site, BikeGlossary. Basically, he’s an engineer and researcher. He has Electrical and Electronics Engineering(EEE) degree in his bachelor's and master's. Besides, he also does product research on different electronics and electric products to share different findings with people. Rudy has a team consisting of 3 members who are also closely working with him.
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