Starter Motor, How they Work (Parts 4) -The motor and gearbox
Behind the starter motor is the motor itself - sometimes directly connected to the drive but more frequently these days through a gearbox.
The aim of the gearbox is to reduce the size of the starter motor required. A smaller, higher revving motor can now be used with the added advantages of lower weight and current requirements. The downside is that the armature is now spinning very fast indeed and the gearboxes have been known to fail.
The gearboxes themselves are relatively simple to repair and on the whole can easily be tacked by any competent D.I.Y mechanic.
