Are Motorcycles equipped with alternators? An Engineer’s Simple Explanation

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It can sometimes be frustrating and confusing to try to understand the motorcycle’s electrical system. Motorcycles have to generate electricity somehow; without it, headlights, blinkers, and even starting it in the first place wouldn’t be possible.

You’ll hear terms such as “alternator,” “stator,” “rectifier,” “magneto,” But what does this all mean for motorcycles? The word “alternator” It is perhaps the most commonly used term. Many wonder if a motorcycle actually has one.

Do motorcycles have alternators? Most motorcycles have a type of alternator that is used to charge/power it’s electrical components while it is running. The alternator is also commonly used to power a motorcycle’s electrical components. “stator” It is usually accompanied by a regulator/rectifier. A simpler system is required because a motorcycle’s size makes it more difficult to use regular alternators.

It’s important to know how the charging and electrical systems work on a motorcycle if you are planning on owning one. I have dealt with many motorcycle electrical components and own over a dozen bikes, so I am able to explain what an alternator system for motorcycles is and how it works.

How a motorcycle alternator works

The term “alternator” is thrown around casually when discussing how a vehicles keeps up with powering it’s electrical components. The word “The Word” is a loosely defined term that refers to the power of an automobile’s electrical components. “alternator” It is more of a generic term, and it is used to describe the way a vehicle produces electricity by producing alternating current (or AC).

An alternator is a device that converts mechanical energy to electrical energy. Many vehicles, including motorcycles, will include some type of alternator. The alternator on a motorcycle is often referred to more commonly as the “stator.” A stator is a simpler version of an alternator than the ones found in larger vehicles like cars. The stator is located within the motorcycle engine and is considered part of it.

The rotor (also known by the flywheel), the stator and the field coil are the three essential components of a motorcycle stator. The basic functions of a stator are simple. AC (alternating current), is created when the flywheel revolves around the stator, while the motorcycle is running. Copper coils are placed around each spoke to organize them around the stator.

Magnetism creates the current. Two sets of magnets are found in the system of a stator. One is stationary and one is on the flywheel. When the magnets on the flywheel rotate around the magnets on the stator, it generates that current which is then delivered to the battery to sustain it’s voltage.

Batteries aren’t able to store AC current. The battery cannot store AC current. Before power is provided to it, it must pass through a regulator/rectifier. The rectifier converts AC to DC (or direct curent). In the meantime, the regulator ensures the right amount of voltage is delivered to the battery and doesn’t overbear it.

Regulator/rectifier is a part of the alternator system. It is often located in a different location than the stator on motorcycles. It’s commonly located somewhere in the air stream so it can be naturally cooled while it works it’s magic. The length, winding, and size of the copper wire that is coiled around the spokes all depends on the motorcycle and the amount of power it needs to keep it’s electrical components functioning.

A battery is not enough to power a motorcycle. If it did, it would quickly drain the battery and you would need to recharge your battery often. Otherwise, you’d likely end up stuck in the middle nowhere with a dead motorbike.

The battery’s functioning is maintained by the stator mechanism. The engine’s mechanisms, which are connected to the flywheel, will turn the motorcycle once it is on.

The kinetic energy (or the power of motion) from the motorcycle engine crankshaft gets the mechanism of the stator to start working, rotating, and generating the current to deliver back to the battery and restore it’s charge. Essentially, the motorcycle is able to recharge itself once it’s on.

These Types of Alternators Are Why Motorcycles Have Them

Although it is an easy mechanism, the alternator system plays a crucial role in keeping a vehicle running. The stator (alternator system) in a motorcycle is different to what other vehicles use. Many wonder why it’s different if it’s such a simple process.

If you’ve ever seen an alternator from a car, you’ll see that they’re bulky and take up a bit of room. Because motorcycles are simpler than cars, they require fewer complex parts. That’s why a motorcycle uses the system of a stator instead of a whole regular alternator. There simply isn’t the room to fit a large part like that on a motorcycle.

Before the introduction of stators, a magneto was used more often on motorcycles. Although it served the same purpose as a stator, delivering the required power to the spark plugs and creating the combustion that the engine needed, the magneto was simpler. Manufacturers started to implement them on their motorcycles, as the technology for alternators and stators improved.

Since then, stators have been used on all motorcycles and are still in use today. They’re a perfect middle ground between a basic magneto and the more complicated and bulky alternator found in cars.

Motorcycle alternators vs. other vehicle alternators

An alternator system is required for all vehicles. It helps to maintain the electrical components and start it up again every time it turns on. Let’s compare the similarities and differences between a motorcycle stator and other alternators.

The basic function of a motorcycle stator or other vehicle alternators (e.g., an alternator from your car) is the same. A car alternator actually has a stator within it that is made up of copper wires wrapped around spokes.

They have the magnetized motion. One set is stationary, the other is spinning around. This generates the power needed to run the vehicle. Each has a regulator/rectifier which ensures that the battery receives the right voltage and amount.

Although a motorcycle stator and an alternator are almost identical, there are major differences. The biggest difference is that alternators found in other vehicles usually has everything put together in one single part whereas a motorcycle stator and it’s accompanying parts are somewhat dispersed throughout the bike.

The way the magnets rotate around each other is another big difference. In other vehicles, such as a car, an alternator receives it’s rotating mechanism indirectly from the engine. The alternator is connected to the engine by a series or belts. A stator is generated directly from the engine since it’s located inside the engine itself.

The Battery’s Function

A common question I’ll often get when explaining how a stator works on a motorcycle is about the function of the battery. If the stator is generating the current the motorcycle needs to function, then what’s the point of having a battery?

A motorcycle battery can’t function without a motorbike stator, and the stator cannot work without the battery. Though the function of the battery is brief, it’s also very important. The battery is what starts the motorcycle.

A stator doesn’t start working and generating power until the motorcycle is actually on. In order to get to that stage, the battery uses it’s current to get the motorcycle started which in turn gets the stator working.

There isn’t much functionality of the battery outside of getting the motorcycle started, but it’s obviously an important part. A battery is used to start a motorcycle. It supplies power to spark plugs to create a spark. This spark ignites the fuel mixture and air the carburetor/fuel injector are providing. The engine will start to work once the combustion has started. Once the engine has turned on, the stator will take over all electrical components.

It takes some power from the battery to get the motorcycle started in the first place so it’s left with a little less power than before the motorcycle started. The stator replaces the energy that was used by the battery to get the bike running.

What Happens When The Alternator/Stator Doesn’t Work

There are some tell-tale signs that the stator on your motorcycle is going out and it’s important for riders to be aware of the symptoms. If you own a motorcycle long enough, you’ll likely run into issues with your stator at one point or another.

The first and most obvious sign the alternator system on your motorcycle isn’t functioning properly is that your battery doesn’t really seem to be holding a charge. You may notice your motorcycle acting a little slow and the lights seem to dimmed more frequently over a short time. Your motorcycle may eventually stop functioning while on a ride.

The motorcycle’s only source of power is its battery. Because it has only so much power, a motorcycle can’t function for long without battery power.

Your motorcycle will likely struggle getting into or staying in high RPM’s. A revved engine requires more power and if the stator isn’t working, all of that power is coming from the battery which may not have enough current to give at high RPM’s. If you’ve noticed when you try to suddenly accelerate or rev your motorcycle engine and it dies, a bad stator may be the issue.

You may also experience the following symptoms: “whirring” Sound coming from one end of the engine It will sound like turning a crank to turn a flashlight. That means the magnetism in the stator isn’t working.

If you are unsure if a defective stator is the problem, you can inspect it manually. Check with your owner’s manual to know it’s exact location on your bike. This usually involves removing one side cover from the engine. Check the condition and appearance of the stator. Are there burn marks, frayed copper wiring, or melted parts?

It is also possible to check the stator by using a multimeter. This is done by finding the stator connector, and then running an AC test. Each terminal should have the same voltage readings. If you see one reading differently, it is likely that the stator is defective.

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