The central laminated core is made of up several thin layers of sheet metal, with the copper wires wound around and in between the iron sheet layers in a predetermined manner. This entire component, with the shaft, sheet metal and copper wires are then laminated and cured in a furnace. The lamination ensure that there are not electrical shortages between the three components.
The lamination and the copper wire are separated by thin pieces of paper, which are then kept intact by the lamination process, and appropriate string.
When a current is applied to this copper winding, a magnetic field develops. The Loops of wire used is called an armature.
This entire laminated armature shaft is then placed in to the starter motor housing. Onto the housing of the starter motor is fixed more sets of copper wire loops, called a stator. The armature spins inside of the stator via bushings and bearings. The clearance between the two can be as little as a millimeter.
As per starter motor wiring diagrams, current is passed through the stator and the armature at the same time. The tractor starter produces a fixed magnetic field that can be likened to the force of a strong permanent magnet.
The armature, being mounted onto bearings and bushings, will have its own magnetic field induced in it from the current. This magnetic field will react to the magnetic field of the stator, producing a motion in one direction as per Fleming s Left Hand Rule.
There are many other parts that are used in a start motor construction namely screws, springs, end plates, solenoids, commutator brushes, and drive gears. These additional parts will complement the two sections of the starter, i.e., the armature and the tractor starter.