Electrolux W4400H Service Manual page 161

Motor
161
The motor control is also able to deliver various instantaneous and output
values during constant speed, acceleration and retardation. These values
are used to calculate the weight of the loaded laundry and to detect any
load imbalances. A separate imbalance breaker can also be connected to
the motor control.
The safety system of the machine includes double detection of the door
lock. Both the programme unit and motor control use different switches to
detect proper door locking. The motor cannot start unless both switches
verify the door is locked.