How does a crank motor work ?

Whether you are a novice or an amateur, it is always interesting to understand how the hardware of your eBike works. This can make it easier to identify a fault or simply enrich your knowledge in a booming environment.

In this article, we are interested in the Bafang crankset motor. This electric motor is available from OZO in several versions which differ in their power (from 250W for the BBS01 in 36V to 1500W for the BBSHD in 48V) but which have the same operating principle, described in this article. This crankset motor has a controller (diagram below) directly molded into the housing. Accessories can then be added to this engine (accelerator, brake cut-off, etc.).

How does an electric motor work ?

The motor is supplied by the battery with current (Amperes) and voltage (Volts). Once in the motor, the current is divided (in the controller) into 3 alternating current phases, also called motor phases which will power the stator winding (diagram below). You should know that the winding, which represents all the copper part in the stator, is in fact divided into 3 coils (not visible on the diagram). Each phase therefore feeds a coil

In this article, we are interested in the Bafang crankset motor. This electric motor is available from OZO in several versions which differ in their power (from 250W for the BBS01 in 36V to 1500W for the BBSHD in 48V) but which have the same operating principle, described in this article. This crankset motor has a controller (diagram below) directly molded into the housing. Accessories can then be added to this engine (accelerator, brake cut-off, etc.). These variations of current in each coil will create a magnetic field and thus modify the polarity of the poles. These electromagnetic forces will subsequently cause the rotation of the rotor via its magnets (diagram)

In addition to having several variants of engine power, the other advantage of this crankset motor sold at OZO is that there is the possibility of adapting several accessories so that your bike corresponds exactly to your use.

Secondary components of the crankset motor kit

Accelerator

In addition to the pedaling assistance of the engine, you can also install an accelerator on your bike. There are several types: trigger (quad type), handle or pivoting half-handle (motorcycle type), with battery gauge, push button, etc.

Display

The display allows you to enter a lot of information about your journey (speed, range, assistance mode, etc.). Several models are available (black and white screen, color screen).

Brake cut-off

The brake cut-off is a safety accessory, it allows you to cut the engine when you apply a simple pressure on the brake. The brake cutoff sold at OZO is actually a sensor that fits into your braking system. There are 3 types: the brake cut-off for cable brakes, that for hydraulic brakes and the brake handle complete with integrated switch.

Derailleur cut-out

A derailleur cutout cuts off the engine when changing gear. This will prevent damage to your transmission, especially when mountain biking. It works on the same principle as the cable brake cut-off, with a sensor that fits around the derailleur cable. When changing gears, the derailleur sensor detects the movement of the cable and cuts the engine briefly.

Transmission

It is possible to install a 32, 34 or 36 tooth chainring to vary the behavior of your bike (torque, speed). An adapter is also available from OZO to integrate your chainring with 4 holes (4x104mm), or 5 holes ( 5x110mm, 5x130mm or 5x135mm). The Bafang crank motor also offers the possibility of installing a double chainring.