Starter Home Page
What is a Starter?
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What does a starter do?
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The simple definition:
A starter is a device that converts electrical energy to mechanical energy.
Sounds simple enough, right? So how does it really work?
First, the cars battery provides electrical energy to the starter through the main battery cable. When you turn the key all the way forward to the start position the solenoid moves the starter gear into contact with the flywheel gear and then, and only then, the starter motor begins to spin. Since the starter gear and flywheel gear have meshed together this spinning motion is transferred to the flywheel which is attached to the crank shaft. The starter spins the engine until it begins to run on its own. Then when you let go of the key the solenoid then moves the starter gear away from the flywheel gear. The video below shows this process in detail. Check it out.
Sounds simple enough, right? So how does it really work?
First, the cars battery provides electrical energy to the starter through the main battery cable. When you turn the key all the way forward to the start position the solenoid moves the starter gear into contact with the flywheel gear and then, and only then, the starter motor begins to spin. Since the starter gear and flywheel gear have meshed together this spinning motion is transferred to the flywheel which is attached to the crank shaft. The starter spins the engine until it begins to run on its own. Then when you let go of the key the solenoid then moves the starter gear away from the flywheel gear. The video below shows this process in detail. Check it out.
Now for what goes on inside the starter.
(Non technical readers digest version....really)
Direct Drive Starter
The starter pinion gear is connected to the armature. The armature contains windings, within a core made of metal laminations, that produce a magnetic field when a voltage is applied via the field brushes to the commutator segments. The armature spins within a set of pole pieces surrounded by the field coils. When a voltage is applied to the field coils the pole pieces become powerful magnets with alternating north and south poles. The interaction between the magnetic forces in the armature and that of the pole pieces produces a spinning motion in the armature. A spinning motion so powerful that it is capable of spinning the engines crankshaft until the engine begins to run on its own. **Keep in mind this is just a thumbnail sketch of the internal workings of a starter. Some things have been simplified and others omitted in order to make it short and to the point. For a much more detailed description of starter design and theory as well as many other interesting things click on the following words..... TECHNICAL STUFF PAGE.
What is the purpose of a starter?
A starter is designed to spin the engine until the engine begins to run on its own. Once the starter pinion gear disengages from the flywheel the startes job is done.
So what are the limitations of the starter?
Starters can be run for only a few seconds at a time before they begin to overheat.
During cranking the starter is converting energy from the battery to into a huge amount of mechanical motion. This process produces very high temperatures inside the starter very quickly. Unlike alternators starters have no means of cooling so cranking for more than a few seconds can damage starter components. Many new vehicles have a timer built into the starting system that will not allow the starter to be engaged for more than about 10 seconds at a time. Again to see much more detail about this and many other interesting things click on the following words..
TECHNICAL STUFF PAGE
During cranking the starter is converting energy from the battery to into a huge amount of mechanical motion. This process produces very high temperatures inside the starter very quickly. Unlike alternators starters have no means of cooling so cranking for more than a few seconds can damage starter components. Many new vehicles have a timer built into the starting system that will not allow the starter to be engaged for more than about 10 seconds at a time. Again to see much more detail about this and many other interesting things click on the following words..
TECHNICAL STUFF PAGE
Improvements in starter design over the years.
Offset Gear Reduction Starter
While it is correct to say that the basic principles of the starter motor are the same today as they were when the first starter was designed, many specifics of starter design have changed considerably. For instance the pole pieces, which become powerful magnets when electricity flows through the field coils that are wrapped around them, have been replaced in most modern starters with permanent magnets. Since the energy required to magnetize the pole pieces is not needed the starter uses less power from the battery, making it more efficient. Also, the direct drive design used in the examples above has been replaced in most modern starters with gear reduction drive designs. The starter pictured here is an off-set gear reduction design. The advantage of this design is that it allows for a smaller, lighter starter to produce the same amount of torque as the earlier direct drive starters while using less energy from the battery. Notice the pinion gear is no longer connected to the armature shaft. In this type of design the armature spins about 4 times faster than the pinion gear whereas in a direct drive type the pinion gear turned at the same speed as the armature. For more on gear reduction systems and as well as many other interesting things click on the following words....TECHNICAL STUFF PAGE
ALTERNATORS
LAMPS BRUSHES ARMATURES BRUSH HOLDERS |
WINDOW REGULATORS
DIODES BEARINGS CLUTCH PULLEYS BATTERY ISOLATORS |
STARTERS
FUSES RELAYS SWITCHES SOLENOIDS |
WINDOW MOTORS
DRIVES BUSHINGS BATTERY CABLES VOLTAGE REGULATORS |
GENERATORS
BULBS ROTORS FIELD COILS WIRE SUPPLIES |