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Brushed Vs Brushless Hub Motors

Modern e-bikes all prefer to use "brushless" hub motors, just because they are more durable than the “brushed” counterpart, besides the maintenance cost in them is also very little.

What is the difference between brushed and brushless hub motors?

Brushed Hub Motors

A brushed DC motor uses a configuration of wound wire coils- the armature- acting as a two-pole electromagnet. When the motor is working, the coil and the commutator (a mechanical rotary switch) rotate, the permanent magnets and the brushes do not rotate, and the current direction change of the coil is completed by the commutator and the brush. When the current direction of the coil change, the electromagnet’s poles are changed and push against the permanent magnets along the outside of the motor.

This contact of brushes and commutator wears the brushes that these brushes have to be replaced regularly. This replacement is not so expensive but to manage this work itself is not so easy.

Brushless Hub Motors

A brushless motor utilizes a permanent magnet as its external rotor or internal rotor. In addition, it uses three phases of driving coils and three hall sensors to track the rotor position. When the sensor tracks the rotor position, it sends out reference signals to the controller. Then the controller activates the coils in a structured way – one phase after the other.

The brushless motor adopts electronic commutation, the coil does not move, and the magnetic pole rotates. As there is no physical contact for many parts of the motor inside, therefore there is virtually no wear and tear possibilities, making the motor’s durability limitless. These motors require sophisticated controllers, and it makes it possible for using three different windings, and power is supplied by individual windings according to the position they are in the movement. When the motor passes one winding, the controller passes the power to another winding, making the movement to continue without stopping.





Brushed MotorBrushless MotorProLow cost.High efficiency Require a simple and inexpensive controller.Low maintenance, Long lifespan.no controller needed for fixed speeds.Lower electric noise generation.High-speed rangeConLess efficient, poor heat dissipation capacityHigh costElectric NoisyRequire a complex and expensive controllerRegular maintenance and replacement.

BrocLuno

The starting current underload on DC brushed motors tends to fry the brushes... Three phase brushless are more efficient as long as the controller does its job and does not waste a bunch of watts in heat ...

YuriyLogvin

BLDC (Brushless DC Motors) are probably the most popular type of motors and controllers among e-bikes now. These are the brushless motors with permanent magnets. They’re quite reliable, have a rather high efficiency and relatively simple design. Everything is quite simple with them, manufacturing, operation, service.

Brushed Motors have permanent magnets and a collector. Their design is much simpler, in fact, it’s just a set of keys that change the current that is supplied to the engine. Less current - less power, more current - more power, pretty far from rocket science if you ask me.

For a regular person that wants to have an electric bike, I'd say it’s usually BLDC.

ekline309

Are there any commercially available brushed DC hub-motors? I feel like I've seen a photo of one YEARS back but I would be surprised if anyone was making them now...

unterhausen

Me too, it's probably cheaper in China to make a brushless motor system, particularly considering the easy availability of controllers.

Frankenbike27

simply heat, at 35 c your motor warms up big time with a brushed motor, it's a magnet killer.