MY20K10-02_1.0_10.11.2020
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Overview
3.1.4
Electric drive system
The S pedelec is driven by muscle power applied
to the chain drive. The force which is applied by
pedalling in the direction of travel drives the front
chain wheel. The chain transmits the force onto
the rear chain wheel and then onto the rear wheel.
Figure 7: Diagram of mechanical drive system
1
Direction of travel
2
Chain
3
Rear chain wheel
4
Front chain wheel
5
Pedal
The S pedelec also has an integrated electric
drive system.
The electric drive system is made up of
8 components:
Figure 8: Diagram of electric drive system
1
Control panel
2
Display
3
Integrated battery
4
Rear motor
5
Rear light
6
Torque support
7
Cable harness
8
A charger which is designed for the battery.
3.1.4.1 Motor
The S pedelec has a gearless wheel hub motor.
As soon as the required muscle power from the
rider pedalling passes a certain level, the motor is
activated gently and assists the rider's pedalling
motion. The motor force is determined by the set
level of assistance.
The S pedelec does not have a separate
emergency stop or emergency shut-off button.
The drive system can be stopped in case of
emergency by removing the
display
.
The motor switches off automatically as soon as
the rider no longer pedals, the temperature is
outside the permitted range, there is an overload
or the shut-off speed of 45 km/h has been
reached.
This provides protection against premature power
reduction during long climbs and with heavy
loads, longer assistance on inclines, greater
efficiency and, consequently, less battery
consumption as the motor is cooled to an optimum
extent.
Just like all drives, gearless wheel hub motors are
optimised to an operating point consisting of
speed, load and power. The S pedelec wheel hub
motor is designed to operate within a speed range
between 20 km/h and 45 km/h and a drive power
output of 500 W. The motor achieves its optimum
efficiency and range within this speed and output
range. This means that the electrical energy
supplied from the battery is optimally converted
into electrical drive energy. A motor's efficiency
decreases whenever it is not operated at its
optimum operating point. As a result, the electrical
energy is no longer converted to an optimum
degree since part of the supplied energy is
converted into heat instead. This reduces the
range and the heat needs to be dissipated.
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