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What Is an Alternator in a Car? What Does It Do?

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Actually, what is an alternator? What does it do? Many think a car’s battery runs all of its electrical parts on its own. But for the surprise, the car’s electrical equipment gets most of its power from the alternator, not the battery. An alternator is an internal part of a car. Read to know about the role of an alternator in a car. 

alternator in a car

What is an alternator in a car? 

Alternators are usually near the front of the engine. They are powered by the crankshafts, which turn the up-and-down motion of the pistons into a circular motion. Old cars had separate drive belts from the crankshaft pulley to the alternator pulley. Today, most cars have a serpentine belt or a drive belt. All of the parts depend on the power of the crankshaft. 

The engine doesn’t make electricity because it only makes mechanical energy. So, we need a source of power that makes electricity to power all the electrical parts in your car. So, the alternator comes into play. The car battery, the voltage regulator, and the alternator are all parts of the charging system. Your alternator uses alternating current to turn mechanical energy into electrical energy.  

The alternating current is made by the alternator’s stator and rotor, which work like magnets and turn to make the current. Then, the alternating current (AC) is changed into a direct current (DC) that charges the battery. Both overcharging and undercharging can be bad for your battery. The voltage regulator takes power from the alternator and sends it to the battery. It controls the amount of power going to the battery to get a steady flow of power. 

What are the components of an alternator? 

Every part of an alternator works together to provide the car with the right kind and amount of power. An alternator in your car has many parts, but here are the important ones and what they do: 

Stator and rotor 

The parts of an alternator that produce electricity are the rotor and the stator. The rotor, a cylinder with magnets around it, spins inside the stator, with a set of copper wires that stay in place. In the end, electricity is formed when the magnets move over the wires. 

Voltage regulator 

The voltage regulator monitors how much power the alternator puts out. It keeps track of how much power is sent to the battery and gives power to the rest of the car. 

Diode rectifier 

The diode rectifier is in charge of changing the voltage received from the alternator into a form the battery can use to charge. 

Cooler fans 

Alternators produce a lot of heat and must be cooled to work well. They are made with vents and an aluminum case to help get rid of heat, and they also have rotating fans to help cool them down even more. Older models of alternators usually have fan blades on the outside, while newer ones have them inside. 

Working of an alternator 

We all know that your car gets most of its electricity from the alternator, which also helps charge the battery. But before the alternator can do any of that, it must first convert the energy from the engine into electricity. So, the working of an alternator needs to be explained in two parts. 

How the alternator creates power 

Most modern cars have a serpentine belt that goes from the engine’s crankshaft to the alternator. Older cars may have a separate pulley from the crankshaft to the alternator. The movement of the belt, which is the source of mechanical energy, makes the rotor of the alternator spin quickly inside the stator.  

As the rotor spins, electricity is produced. The magnets around the rotor are put there on purpose so that when they pass over the copper wires in the stator, they create a magnetic field. In turn, this magnetic field makes voltage caught by the stator. The power then goes to the voltage regulator, which sends power to the car and controls how much power the battery gets. 

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Source: Tenor

How the alternator charges the battery 

The power from the alternator needs to be changed into a form that the battery can use. Because electricity can move in different ways or currents. Batteries use direct current (DC), while alternators make electricity called alternating current (AC), which sometimes flows backward. So, the power necessary for the battery passes through a diode rectifier to turn it into DC before it goes to the voltage regulator. After the change, the power can be used to charge the battery. 

Signs that your car’s alternator is worn out 

Most of the time, alternators don’t need much attention unless worn out. Most of them last between 7 and 10 years in the best conditions. But there is more than one way to understand if your alternator is worn out. Following are some signs that mean your alternator is crying out for help.  

Your car battery needs charging 

If you have to keep giving your battery a boost, it could mean that your car needs an alternator replacement.  This happens when the alternator fails to charge the battery. 

Your car stops frequently 

Many things could cause your car to stop running, but a bad alternator is one of them. If your car can’t get power from its alternator, it can’t move, so it stops. 

Your car dashboard lights go dim 

Most of the time, a bad alternator is to blame when the lights on your dashboard are dim. But don’t immediately think that the problem is your alternator. Instead, take your car to a mechanic for inspection. 

The electronics malfunctions 

If your electrical gadgets malfunction, it could mean that your alternator is broken. You will need enough power for the accessories to work in the best condition at full. But if the alternator can’t provide that power, they will get less efficient. 

alternator in a car

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