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Friday, 15 August 2008

Motorcycle Stators - What Are They?

After struggling with my Honda CX500 stator, I'm bit curious about this electrical thing. Then found this article from Electrosport.





In simple terms, a stator can be defined as the stationary part of an alternator. In order to understand what the stator does, it is helpful to know how a basic electrical system works.


The electrical system on most vehicles includes a way to generate, store, and use electricity. An alternator generates power by producing AC (alternating current). Alternating current is often used exclusively to power halogen bulbs, tail lights, and some ignition systems on mopeds, dirt bikes, and ATVs. Any motorcycle that has a starter motor must also have a battery for powering it. Batteries cannot store AC current; therefore current must be converted into a storable form known as DC (direct current). A component known as the regulator/rectifier performs this conversion. The rectifier actually converts the current from AC to DC, while the regulator keeps the power level (voltage) from going above the 13.8 -14.5 volts needed to power a standard 12 volt battery. It is important that the stator provides more power than needed by the motorcycle so that the battery will stay charged. If the motorcycle uses more power than the stator can provide, the battery will start to drain. This will typically happen if the voltage drops below 13 volts.

A traditional alternator uses a coil that uses DC power from the battery to produce a magnetic field. This coil is wound on a spool and is sandwiched between two metal flywheels with fingers of metal that alternate from one side to the other. When this coil is powered, it makes each finger have a magnetic field. These alternate with each finger between north and south pole. As this assembly spins, the alternating poles of magnetism energize the outer windings of the alternator to produce AC power. The benefit to this type of system is that it can produce more power at lower engine speeds which is why most cars and trucks use this system. The down-side to this system is that it requires a charged battery to work. Motorcycles often require a lighter weight system that can produce power with no battery installed or with a small battery. This requires a slightly different way of making power.

The alternator on a motorcycle or ATV converts kinetic energy (power of motion) into electrical energy to charge the battery. An alternator is made up of two parts; the stator and the magnet rotor, also known as the flywheel. The rotor or flywheel contains permanent magnets and spins around the stator to produce energy. Energy use varies from motorcycle to motorcycle and as a result, individual stators may differ. Some stators produce AC power for the ignition system only while others produce AC which is then converted to DC for powering lighting, ignition computers, fuel injection, etc.

Stator designs vary widely but all work on the same principles. When a magnet is moved past a coil of wire, it causes the coil to produce a burst of electricity. A stator has between four to eighteen spokes or poles arranged in a circle similar to the spokes on a wagon wheel. These spokes have an iron core made of a number of thin plates stacked on top of one another. Each spoke has copper magnet wire wound around it. Some stators use a single coil spread across a few poles while others use a few coils with different windings and wire sizes on a single stator.

Still others are split into three evenly divided sections called three-phase, used for high powered output to be converted to DC. Three-phase stators are easily recognizable by three yellow or white output wires. The winding, length, and diameter of the copper wire is customized to suit the power requirements of each motorcycle, as well as optimize the ignition system's power output and starting capability.

Some stators include a pulser or pickup coil. This small coil is mounted separately to the motor or to a mounting plate, allowing it to sense the crank angle via one or more small bumps on the outside of the flywheel. The coil must be placed between 0.02 and 0.50 mm away from the highest part of this bump or "trigger". The input from this coil is sent to the ignition computer (CDI), where the spark timing is calculated. Some CDIs are powered with AC power from a specific coil, called a source coil, which is wound with fine wire. Other CDIs may be powered by DC current produced by a stator, regulator/rectifier, and battery combination. The current from the CDI is sent to the ignition coil and magnified to over 10,000 volts. It is then sent to the spark plug.

Most of our stators include a full wiring harness allowing for easy installation. It is important to note that we often include upgraded features on our performance stators, and as a result, these stators may look slightly different than the OEM units. In addition, some of the testing procedures used for OEM stators may not apply to our parts due to optimized windings.

SAVING GAS TIPS

This issue "popular" again,

ENGINE WARM-UP

1. Avoid prolonged warming up of engine, 30 to 45 seconds is enough (even in winter time), for old car (more than 6-7 years old) probably needs a bit more time (1-2 minutes)

2. Check/listen to the rpm idle, be sure the automatic choke is disengaged after engine warm up.

3. Don't start and stop engine needlessly. Idling your engine for one minute consumes the gas amount equivalent to when you start the engine.

4. Avoid "reving" the engine, especially just before you switch the engine off; this wastes fuel needlessly and washes oil down from the inside cylinder walls, owing to loss of oil pressure, this process also can damaged your turbo system if equipped

5. Eliminate "racing type" starts. Accelerate slowly when starting from stop, at least for the first 200-300m.

BUYING GASOLINE

1. Don't let your fuel tank close to empty, empty fuel tank store more fuel vapour and increase pressure in gas tank

2. Buy gasoline during coolest time of day - early morning or late evening is best. During these times gasoline is densest. Keep in mind - gas pumps measure volumes of gasoline, not densities of fuel concentration. You are charged according to "volume of measurement".

3. Choose type and brand of gasoline carefully. Certain brands provide you with greater economy because of better quality. Use the brands which "seem" most beneficial.

4. Avoid filling gas tank to top. Overfilling results in sloshing over and out of tank. Never fill gas tank past the first "click" of fuel nozzle, if nozzle is automatic.

DRIVE ECONOMICALLY

1. Never exceed legal speed limit. Primarily they are set for your traveling safety, however better gas efficiency also occurs. Traveling at 55 mph give you up to 21% better mileage when compared to former legal speed limits of 65 mph and 70 mph.

2. Traveling at fast rates in low gears can consume up to 45% more fuel than is needed.

3. Manual shift driven cars allow you to change to highest gear as soon as possible, thereby letting you save gas if you "nurse it along". However, if you cause the engine to "bog down", premature wearing of engine parts occurs.

4. Keep windows closed when traveling at highway speeds. Open windows cause air drag, reducing your mileage by 10%.

5. Drive steadily. Slowing down or speeding up wastes fuel. Also avoid tailgating - the driver in front of you is unpredictable. Not only is it unsafe, but if affects your economy, if he slows down unexpectedly.

6.Think ahead when approaching hills. If you accelerate, do it before you reach the hill, not while you're on it.

GENERAL ADVICE

1. Do not rest left foot on floor board pedals while driving. The slightest pressure puts "mechanical drag" on components, wearing them down prematurely. This "dragging" also demands additional fuel usage.

2. Avoid rough roads whenever possible, because dirt or gravel rob you of up to 30% of your gas mileage.

3. Use alternate roads when safer, shorter, straighter. Compare traveling distance differences - remember that corners, curves and lane jumping requires extra gas. The shortest distance between two points is always straight.

4. Stoplights are usually timed for your motoring advantage. By traveling steadily at the legal speed limit you boost your chances of having the "green light" all the way.

5. Automatic transmissions should be allowed to cool down when your car is idling at a standstill, e.g. railroad crossings, long traffic lights, etc. Place gear into neutral position. This reduces transmission strain and allows transmission to cool.

6. Park car so that you can later begin to travel in forward gear; avoid reverse gear maneuvers to save gas.

7. Regular tune-ups ensure best economy; check owner's manual for recommended maintenance intervals. Special attention should be given to maintaining clean air filters... diminished air flow increases gas waste.

8. Inspect suspension and chassis parts for occasional misalignment. Bent wheels, axles, bad shocks, broken springs, etc. create engine drag and are unsafe at high traveling speeds.

9. Remove snow tires during good weather seasons; traveling on deep tire tread really robs fuel!

10. Inflate all tires to maximum limit. Each tire should be periodically spun, balanced and checked for out-of-round. When shopping for new tires, get large diameter tires for rear wheels. Radial designs are the recognized fuel-savers; check manufacturer's specifications for maximum tire pressures.

11. Remove vinyl tops - they cause air drag. Rough surfaces disturb otherwise smooth air flow around a car's body. Bear in mind when buying new cars that a fancy sun roof helps disturb smooth air flow (and mileage).

12. Auto air conditioners can reduce fuel economy by 10% to 20%. Heater fan, power windows and seats increase engine load; the more load on your engine, the less miles per gallon.

13. Remove excess weight from trunk or inside of car - extra tires, back seats, unnecessary heavy parts. Extra weight reduces mileage, especially when driving up inclines.

14. Car pools reduce travel monotony and gas expense - all riders chip in to help you buy. Conversation helps to keep the driver alert. Pooling also reduces traffic congestion, gives the driver easier maneuverability and greater "steady speed" economy. For best results, distribute passenger weight evenly throughout car.

15. During cold weather watch for icicles frozen to car frame. Up to 100 lbs. can be quickly accumulated! Unremoved snow and ice cause tremendous wind resistance. Warm water thrown on (or hosed on) will eliminate it fast.

EXTRA TIPS

Use public transport ........

originally written by Ernest Miles, modified by Explorer