XC90 L5-2.5L Turbo VIN 59 B5254T2 (2004)
When the starter motor rotates, the sun wheel rotates clockwise. The planetary gears, which are constantly engaged with the sun wheel and ring wheel,
rotate counter-clockwise. As the ring wheel is secured, the planetary gears are forced to circle around the sun wheel clockwise. The planetary gears rotate
more slowly than the sun wheel. It is the clockwise rotation of the planetary gears which drives the pinion. The speed reduction that occurs between the
sun gear and the planetary gear, results in greater torque. This means that a smaller and lighter starter motor can be used.
Starting the engine
When the moving steel cores for the solenoids reach their limit position the moving switches break the circuit with the fixes switches and the pull-in
winding is disconnected. The hold-in winding keeps the switches closed. The current now passes through the positive carbon brushes and the armature
winding. Grounding is carried out through the negative carbon brushes. This current creates a magnetic field in the rotor, which starts the rotor rotating.
When the rotor rotates, the magnetic field is generated continuously depending on how the commutator and the windings are organized on the rotor. This
allows the rotor to continue rotating.
Note! The starter motor of the V8 engine is equipped with field windings instead of permanent magnets. The field windings are electrically
connected in series with the carbon brushes.
When the ignition key is released the starter motor relay is deactivated and the circuit for the hold in winding is broken. Then the return spring for the
solenoid pulls the pinion back, at the same time as the fixed and moving switches separate and the current to the starter motor is broken.
