Editing Starter motors

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'''PREAMBLE'''

The starter motor itself is a high torque direct current ( DC ) electric motor. Inside are a rotating armature, four brushes and a pair of field coils or permanent magnets (on new models). The starter uses the opposing magnetic forces of the armature and field coils or permanent magnets to convert electrical energy into mechanical energy.
When the ignition switch is turned to the start (crank) position, voltage is routed through a solenoid or relay to the starter motor. As the starter motor begins to spin, the drive gear extends and engages the teeth on the flywheel ring gear to crank the engine. When the engine starts and the key is released, the drive gear retracts and the starter stops spinning. An overrunning clutch in the starter drive prevents the starter from being over-revved and being damaged when the engine starts.

Though most starters are "direct drive," some have an extra set of reduction gears to increase cranking torque. Reduction gears also allow a smaller, higher speed motor to be used. Reduction gear starters are often found on Chrysler and import applications.

Cranking an engine is hard work and pulls a lot of amps out of the battery. The cranking load is even greater during cold weather because low temperatures thicken the viscosity of the oil in the crankcase and increase drag. At the same time, the battery has less amps available because cold temperature slows down the chemical processes inside the battery that release stored electrical power. So if the starter has worn internal components, a poor ground or positive cable connection with the battery, or the battery's level of charge is low, the engine may not crank fast enough to start or it may not crank at all.

Starter problems can be caused by worn brushes (carbon pads inside the motor that supply current to the rotating armature), by shorts or opens in the armature or field coils or by worn bushings that increase drag or allow the armature shaft to rub against the pole shoes.

Excessive cranking on a starter is very hard on it because of the excessive heat that it creates when cranking a poor starting engine. For each minute of cranking allow the starter to cool for five minutes. Some reasons why starters crank to much are: weak battery, loose connections, and mechanical problems located within the engine.

'''PARTS OF A STARTER'''

[[Image:Starter_expl_view.gif‎]]Parts contained in a starter motor

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