How the motor of the MotoE is made and how it works

How the motor of the MotoE is made and how it works
The motor of the MotoE by Energica Motor Company (photo: Jesus Robledo)

The engine is the distinctive element of a motorcycle; in the case of MotoE the electric motor determines its character, riding style and sound. The bikes currently used are the Ego Corsa by Energica Motor Company while from 2023 the sole supplier will be Ducati.

The engine is the distinctive element of a motorcycle and determines its character and image: two-cylinder, single-cylinder, in-line 4 cylinders, V, L. In the case of electric motorcycles, the engine is replaced by the electric motor. Its function is to convert the electrical energy supplied by the battery into mechanical energy to move the bike.
The components used to rotate the shaft of the electric motor are the stator and the rotor; the first is fixed while the second is integral with the shaft and rotates with it. There are also other applications where the roles are the opposite but this is not the case with MotoE. The rotor is set in motion by the magnetic field generated by the flow of alternating current passing through the stator windings. The rotor motion is transmitted to the rear wheel through a traditional chain transmission.

A typical permanent magnet electric motor (PMAC)

The permanent magnet motor is the currently most used type in the automotive and motorcycle applications due to its high efficiency and reliability. Its most advanced version is called Permanent Magnet AC Motor (PMAC).
Another type of electric motor is the synchronous reluctance type (SynRM) which is characterized not only by its high energy efficiency but also by its reliability and low maintenance requirements. MotoE current features a 120kW (about 160HP) and 10300rpm permanent magnet motor. Cooling is mixed: the motor casing is air-cooled also thanks to special fins, while the rotor is oil-cooled.
The element that supplies power to the motor is the battery, but this delivers direct current while the motor needs alternating current to generate the magnetic field in the stator. The conversion function from direct current to alternating current is carried out by the inverter while the modulation of the current to vary the motor rpm is performed by the converter.

The "power electronics" group of MotoE which includes inverters and converters. On the left the connection cables with the battery, on the right those for the power supply of the electric motor.

Here we do not want to go into the details of the operating principle of an electric motor in motorcycle applications, but we prefer to describe how this component characterizes the motorbike and its riding style.
An internal combustion engine is characterized by power and torque which increase with the rpm to a maximum and decrease after that. An electric motor has a power curve that increases with the rotational speed for most of the range until it stabilizes at high revs. The torque curve, on the other hand, has its maximum from zero speed and remains constant for a large part from the range, until it halves at the maximum number of revolutions.

Example of power curve of an electric motor for motorbike applications (photo: Lightfighter)

The torque curves of the electric motor and the internal combustion engine have opposite trends with important effects on the behavior of the motorbike. Referring to the comments of the MotoE riders, at the exit of a slow corner, when the engine is at low rpm, the torque of the MotoE bike is impressive even at the slightest rotation of the throttle. In fast corners, on the other hand, the electric motor works in the area where the torque value is reduced and the rider can twist the throttle completely; that is impossible, for example, with a Moto2 that in the same corner has the engine at maximum torque.

Maria Herrera with the MotoE of the Aspar team

One more important effect of the motor on the riding style of an electric motorcycle is the handling. An endothermic engine is characterized by considerable moving masses, whose gyroscopic effect acts to reduce the handling of the bike. This can be reduced by varying the engine configuration but cannot be fully eliminated. In an electric motor, the only rotating mass is that of the rotor and is extremely little. As a consequence, its gyroscopic effect of very little too. For this reason, an electric motorcycle is much easier to handle than a motorcycle with an endothermic engine of similar weight.
Other elements whose characterize the electric motors installed on the bikes are the simplicity of construction, the reduced maintenance, the high reliability and the low heat generated.
In addtion, we mention the regenerative capacity: during braking, the wheel that is connected to the engine through the transmission slows it down, reversing its operating principle. The result is a flow of current from the motor to the battery which is thus recharged by the motor brake.

In these sections you can find further information and details on MotoE and its main components.

The MotoE Bike
Tyres

The MotoE Bike
Braking system

The MotoE Bike
Suspensions

The MotoE Bike
Motor brake

The MotoE Bike
Data acquisition

The MotoE Bike
Charging system

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