Alternator Buyer’s Guide
- The alternator is a compact generator primarily consisted of a magnetic coil and a metal rod.
- It is typically found in front of your car’s engine, with a pulley attached to the crankshaft via an alternator belt.
- The alternator features an aluminum housing for a few reasons: it is lightweight and does not magnetize.
- Terminals, finger poles, slip rings, diode rectifier, voltage regulator, among others make up the alternator.
- The alternator is connected to the engine via an alternator belt, which links it to the crankshaft. This connection converts the piston’s linear movement into rotational movements.
- If you shop at CarParts.com, you can purchase an alternator replacement with discounted price for as low as $6 to $2,000.
- Maintaining a properly-working alternator has a lot of benefits contributing to cabin comfort, driving performance, ride quality, and saving money.
In able for the lights, air conditioning unit, and other power features in your car to function without draining the battery, car manufacturers integrate a charging system. This charging system does not only power the electric components in your car, it also recharges your battery as the car moves. You’ve heard it before and a lot could go wrong if it fails completely. Ladies and gentlemen, we present to you the automotive alternator.
What is an alternator?
The alternator is a compact generator primarily consisted of a magnetic coil and a metal rod. It’s function is to convert mechanical energy into electrical energy to bypass the battery in powering the electrical components when the car is moving. It is typically found in front of your car’s engine, with a pulley attached to the crankshaft via an alternator belt. It’s almost as big as a football and features various components inside.
The alternator features an aluminum housing for a few reasons: it is lightweight and does not magnetize. Aluminum is known for dissipating intense heat levels unlike steel. Since it can’t magnetize, it remains neutral despite the magnetic field produced by the rotor assembly.
What does an alternator do and how does it work?
A vehicle’s charging system consists of the battery, alternator, and voltage regulator. The alternator takes the battery’s task as soon as mechanical energy is converted to electrical energy. This energy is used to power the electrical components of the car, as well as in recharging the battery. So, how does it do it?
The alternator is connected to the engine via an alternator belt, which links it to the crankshaft. This connection converts the piston’s linear movement into rotational movements. When the crankshaft begins to spin, the alternator belt transfers the movement to the alternator’s rotor shaft. The motion creates electromagnetism through the stator and rotor, which it uses to produce AC power. The charging standards need to be between 13.5 V to 14.2 V, which, by the way, can vary depending on whether two or more electrical features are active at the same time.
Parts of an alternator
The alternator may look simple on the outside, but you’ll have to wait until you get to see what’s inside. Beyond the housing are components needed for the conversion of energy, such as the rotor field windings, diode rectifier, voltage regulator, among others. Alternator parts include:
Most alternators have four terminals that are labelled with letters. The terminal “B” is the alternator’s main output and connects to the car’s battery. Like terminal B, terminal “S” also connects to the battery but for measuring its voltage The terminal “IG”, on the other hand, is connected to the ignition switch , while the “L” links to the warning light. Some alternators have another terminal that serves as the full-field bypass for the voltage regulator.
Internal cooling fan
Most modern alternators are integrated with internal cooling fan to boost the efficiency. You’ll be able to easily distinguish older alternators because they have their cooling fans installed outside the aluminum housing. The fans spin as the rotor shaft gets spun by the crankshaft, meaning it runs on mechanical power.
Also known as the bridge rectifier, this assembly converts the alternating current from the alternator to direct current. Direct current is the charge used by the battery and all other electrical components. Bridge rectifiers use semiconductor diodes to convert AC to DC. These diodes are one-way gates, meaning they allow current to flow from only one direction, thus allowing the conversion of AC to DC.
A voltage regulator is responsible for controlling the voltage being generated by the alternator when recharging the battery. It does this by forcing the alternator to keep a steady voltage between 13.5 V and 14.5 V. These are most ideal for charging the battery without damaging electrical circuits, such as your vehicle’s wiring system.
Slip rings are electrically conductive bands that are mounted on the shaft and are connected to the rotor assembly through windings. The slip ring’s outer surface is in constant contact with the brushes. This is essential in providing direct current excitation to the alternator’s rotor.
Carbon brushes are electrical contacts that conducts electrical current between the slip rings. These brushes are made durable enough to last for several years. They come with wear markings so you’d know when to replace them before they even begin to fail. Experts suggest that you replace them when they’re halfway worn out.
Rotor field winding
The field winding is an insulated current-carrying coil on a field magnet. It produces the right necessary magnetic field intensity to produce an electrical excitation in the alternator.
These are the large triangular pillars surrounding the rotor field winding. These poles are placed with alternating north and south charges that help in creating a magnetic field around the core when the rotor spins.
The stator consists of multiple coils wound through an iron ring and is fixed to the alternator housing. It is a stationary part of the alternator, in which the rotor turns. When the rotor turns within the stator, a magnetic field is produced and travels through the stator windings. This process is what produces the electrical current in the windings. Each stator winding is spaced 120 degrees apart from one another, which then results in three separate sets or phases.
Importance of replacing a worn alternator
Before we talk about the benefits of replacing a failing alternator, you should first be able to pinpoint if the alternator’s the one really causing the problem. The signs of a bad car alternator can be similar to a drained battery. To test this, jump-start your vehicle with a jumper cable. Once your engine is running, disconnect the jumper cable from the terminals. A failing battery won’t kill the engine as soon as you remove the jumper cables. A dead engine shortly after disconnecting the jumper cables is one of the many bad alternator symptoms.
Maintaining a properly-working alternator has a lot of benefits contributing to cabin comfort, driving performance, ride quality, and saving money. If you persist on driving with a busted alternator, even amid the inconvenience it’s causing you, you’ll drain out your battery and may soon go on the fritz for good. To ensure longer battery life, as well as unparalleled driving convenience, replace a worn alternator.
A helpful guide to buying a new alternator
Isn't it cool that cars are equipped with an alternator? This is responsible for converting the mechanical energy into electrical energy through alternating current. In layman's terms, it's used to keep your batteries charged at all times. If it gets damaged, explore the auto retailers to be able to get your hands on that quality alternator. But we can't just let you out on the field without any guidance, so here are some helpful tips on how to get the alternator that every car owner must have.
What kind of alternator should you get?
Before going out to scout for a new alternator, inspect your alternator carefully. Check on your old one because you'd always want to make sure that the new alternator you buy is just the same as the previous one. Otherwise, the new one may not fit properly at all. Next, test the alternator before you head to the cashier to pay for it. You might want to gently shake it; if it rattles, pick another one, if it doesn't, then you're good to go. Also, you'd want to pick an alternator with a good warranty, preferably one that's longer, just in case you need to return it or have it replaced.
Where should I buy the alternator?
You can always buy from recognized online automotive stores in the market selling high-quality alternators. What's good is that you get to shop for them with a few clicks and simply wait for the part to be delivered to your address. Moreover, you should avoid purchasing from local salvage yards because components sold there may have hidden defects. If you're on a budget, there are cheaper alternatives online. Purchase high-quality alternators from trusted brands.
These are just a few tips for you to bear in mind when shopping for a new alternator. Although, you have to be extra careful not to drop the new alternator because the interiors are very fragile and could easily be broken during impacts. So be able to explore because the decision is always in your hands. Good luck and enjoy shopping!
How much does an alternator cost?
An alternator replacement cost around $40 to $2,600 in the market. If you shop at CarParts.com, you can purchase an alternator replacement with a discounted price for as low as $6 to $2,000. Alternator prices vary depending on the brand, product’s amperage output, and whether it’s remanufactured or new. Alternators in the list also feature different pulley types with varying numbers of grooves. To get a narrowed-down list of products specific to your vehicle, you may indicate the year, make, and model of your car in the filter tab.
Repairing Your Old Alternator: DIY Tips
Alternators keep your batteries charged at all times. If this gets damaged, it wouldn't be able to suppy power to the vehicle's different components. Often times, the alternator just malfunctions and doesn't require to be replaced. Usually, repairing it will just do the trick and you're ready to run your vehicle. If you're an experienced DIYer, then this will be slightly easier for you. However, if this is your first time, you might want to be careful because this is not an easy job. But to make your repairing process a whole lot easier, here are steps to help you out to fix your busted alternator.
Difficulty level: Difficult
- Phillips screwdriver
- Slotted screwdriver
- Alternator rebuilding kit
- 1/4 inch drive socket set and wrenches
- 3/8 inch drive socket set and wrenches
- Carburetor cleaner
Step 1: Park your car and set the emergency brake; you certainly wouldn't want it to unexpectedly rolling while working on it. Lift the hood and remove the negative battery cable. With the correct socket, loosen up the alternator adjustment to be able to remove the alternator belt. Next, disconnect the wires that lead from the back of the alternator. Make sure you mark the path with a chalk so you won't get lost when you reassemble it. Loosen the bottom alternator bracket bolts and then you can pull out the alternator.
Step 2: Using the chalk, mark the case of the alternator where it separates at the seam so that you'd be able to reconnect it the same way. If you notice that there are four screws that hold the case, remove it to be able to pry it open. But be careful, the alternator is very fragile. Check the stator winding section; if they look black and have a burnt smell, the alternator cannot be fixed and must be replaced.
Step 3: Take out the screws to the voltage regulator and remember to keep the nylon insulator washers and grounding screwed together. Then, take out the rectifier and bolt stud from the back of the alternator.
Step 4: Get rid of the pulley nut and remove the spacer and fan as well, using the socket. Next, pull the rotor immediately. Apply grease to the shaft threads of the stator and clean the shaft with a rag.
Step 5: To remove the front bearing, take the bearing out of the case. You might want to carefully tap the rear bearing with a hammer and wipe the insides to clean it. Place the new kit inside the case and screw the front bearing back on.
Step 6: Using the small socket, install the new rectifier gently. Secure the new voltage regulator and screw in the new diode. Make sure that you use the insulator that you took off.
Step 7: Put the stator ring back in. To do it easier, you can bend the tabs. Then, reinsert the four long bolts and tighten them using a small socket. Install the pulley and screw in the nut.
Step 8: Mount the alternator back. Loop the alternator belt around the pulley and as you tighten it against the belt, you are also adjusting the nut. Tighten the bolts, reattach the wire terminals, connect the negative battery, and rev up your engine.
Repairing the alternator may not be that easy, but if it's your first time, it's a good idea to ask for some help. Good luck!