​Alternators 101 - When, Why and How to Replace an Alternator

Villa Ford has affordable prices on genuine OEM Ford parts, which is the easiest and best solution when you are replacing an alternator. If you reside in Orange, Santa Ana, Los Angeles or local towns in Southern California, you can enjoy the beautiful weather as you work on your Ford or drop it off to have the work completed. Enjoy beautiful Orange Plaza when you visit Ford Villa, which is a well-known destination for antique shopping and offers trendy clothing boutiques and casual or upscale dining. 

What is an Alternator?

The alternator is the critical component in the automobile's charging system that recycles battery power while the vehicle is operating. The alternator replenishes energy to the battery that was used to manage the auto's climate, engine, entertainment and other systems within the vehicle. The vehicle's condition, the electronics used, the vehicle's mileage each play a role in the life of an alternator.

Signs of a Bad Alternator

1. Dim dashboard and headlights

2. Problems starting the vehicle

3. Repeatedly needing to be jumped even when the battery is completely charged 

4. Alternator warning light or a dash light warning

5. An odd odor from the engine caused by the belt

6. Pulsating headlights, which brighten and dim

7. Burning smell from battery or alternator

8. Radio or electrical components stop working intermittently

9. Squealing noise may be heard in the engine

The Alternator and Charging System

The alternator is a part of the automobile's charging system, which is comprised of three major parts: 

• Battery 

• Voltage regulator 

• Alternator

The alternator's purpose is to work with the battery to the generate power to the electrical components in the vehicle, such as the interior and exterior lights and instrument panel. Alternator refers to an alternating current (AC).

Where is the Alternator Located?

The alternator is usually located closer to the front of the engine and is driven by the crankshaft, which changes the pistons prior up-and-down movement to a circular movement. Older vehicles used a drive belt between the crankshaft pulley and the alternator pulley, but modern cars use a serpentine belt or a single belt that drives all of the engine components that are powered by the crankshaft. Alternators are usually mounted with bolted brackets on the engine. One bracket is fixed and the other is adjustable to tighten the drive belt.

How Do Alternators Work?

Alternators are usually small and are enclosed in an aluminum housing, which is naturally lightweight and non-magnetic. Aluminum is used on the housing to dissipate the heat produced by the electrical power and because the rotor within the alternator is magnetic. 

The alternator has vents on the front and back to aid in heat dispersion, and a drive pulley is attached to a rotor shaft on the front. When the vehicle's engine is operating, the crankshaft turns the drive belt, which then spins the pulley that is on the rotor shaft. The alternator is used to transfer energy from the engine into electrical power for the vehicle's accessories.

There are five terminals located on the exterior back of the alternator. 

• S terminal, which senses battery voltage

• IG terminal, which is the ignition switch for the voltage regulator

• L terminal, which closes the warning lamp circuit

• B terminal, which is connected to the battery

• F terminal, which is a full-field bypass

Older units have external fans on the rotor shaft behind the pulley, while the newer units have cooling fans inside the housing. Outer and internal fans operate using power from the spinning rotor shaft.

Alternator Parts

• Diode rectifier (or rectifier bridge) 

Converts power

• Voltage regulator 

Distributes power produced by the alternator and outputs to the battery

• Slip rings

Help conduct current to wire field

• Brushes

Help conduct current to wire field

Inside of the alternator is the rotor, which is a large cylinder with triangular finger poles around its circumference. The alternator generates power through magnetism. The triangular finger poles are staggered, so that the north and south finger poles alternate and surround the wire rotor field windings, which creates a magnetic field and induces the voltage into the stator. The stator then harnesses the power generated by the spinning rotor.

Diagnose the Problem - Is it the Alternator?

Alternators employ moving parts that are subject to soil and stress from intense heat and cold. This causes the alternator's internal components to wear out gradually. The most common problem is caused by bearing failure. The needle bearings help the rotor to spin inside the stator freely and can break from dirt and heat. Without the bearings, the rotor can not spin efficiently and will eventually seize. Needle bearing failure creates a loud grinding noise, and the alternator will soon stop working. 

There are several easy steps to diagnose when the alternator is failing

The alternator can operate with just one of stator windings operational, but will only be one-third productive. To test if there is an issue with one of the stator windings, use a voltmeter and check the voltage. This is a called a load test. The battery produces DC power, so set the voltmeter to DC and connect the leads to the battery. Connect red to the positive and the black wire to the negative terminal. Turn all vehicle accessories off, and start the car. Raise the RPM to around 1,000, and the voltage will register to around 14-volts. If it registers less than 12-volts, this indicates a problem. 

Turn on the accessories, including the headlights, air conditioning, radio and anything that uses electrical power. Now rev the engine and read the voltmeter. It should register around 14-volts. If the alternator is failing, it will read significantly lower than 14-volts, and it's probably time to replace your alternator.

Before you decide to replace the alternator, check your serpentine belt. If it is worn or loose, it could be the cause for the alternator's malfunctioning. The belt is easily replaced and inexpensive. Replace this belt and then complete steps one and two again. If the voltage is still low, the alternator needs to be replaced.

Your Battery Life and a Bad Alternator

A bad alternator can ruin your battery if you don't address the issue quickly. Batteries will lose their ability to hold a charge if they are often recharged. For the most part, your battery should survive being drained and charged while you determine the problem. But an older battery may need to be replaced as well. Batteries that are drained of power and charged repeatedly will have a significantly shorter life. The average life of a car battery is approximately 48-months.

Who We Are

Villa Ford, a proud member of Wilson Automotive, is located in Orange, CA, and offers Ford parts and accessories at wholesale prices to Southern California residents in Southern California, Los Angeles, Orange and online buyers in the US. 

Villa Ford's team of part specialists will happily answer any questions about fitment or installation. Please don't hesitate to call 714-282-5287 or to visit us online at VillaFord.com. To place an online order, enter your vehicle's VIN or the make, year and model, and enter alternator in the search bar. 

We have years of experience with Ford parts and accessories, and we know our stuff. We look forward to working with you!