When it comes to powering your car’s radio, headlights, and other electronic components, you may think it’s the battery that’s putting in all the work. In reality, it’s your alternator that keeps things up and running. But what exactly does an alternator do, and how does it work? Read on to find out what makes your alternator so important and how to recognize car alternator problems before they become a major issue.

What Is A Car Alternator?

Under the hood, an alternator looks like a small cylindrical generator. You will typically find it bolted to the engine. A car alternator, along with the battery and voltage regulator, is one of three main parts of a vehicle’s electric charging system. What an alternator does is supply electricity to be stored in a vehicle’s battery. It is the alternator’s function to take in mechanical power from a drive belt or serpentine belt connected to the engine’s crankshaft pulley and then convert this mechanical energy into electricity.

Alternator Components

Pulley

Along the exterior of the alternator is a pulley driven by a drive or serpentine belt. The engine’s crankshaft pulley powers the belt, which spins the alternator pulley. The movement from the alternator pulley allows the vehicle’s alternator to function by providing mechanical energy it can convert into electrical energy.

Rotor

The rotor is a cylindrical part attached to a metal shaft that is spun by the alternator’s drive belt. The rotor has a triangle pattern (called triangle finger poles) all around the outer circumference. These triangles are magnetic and have alternating north and south orientations around the rotor.

As the alternator rotor is energized, it becomes an electromagnet at its core.

Stator

The stator encases the spinning alternator rotor.

Attached to the interior of the stator is a series of 3 copper wire windings. As the magnetized rotor spins, alternating current is induced in the stator windings.

Voltage Regulator

While you may think you can’t have too much of a good thing, too much voltage can actually damage your car’s battery and other electronics. This is where the voltage regulator comes into play. The voltage regulator is the part of an alternator used to control the electrical output. The voltage regulator moderates the electricity creating the electromagnet in the rotor into the desired alternator output.

Rectifier

An alternator’s stator creates an Alternating Charge (AC) charge, but car batteries are powered by a Direct Current (DC) charge. The role of a rectifier is to convert the alternating electric charge into direct power that’s compatible with the vehicle’s battery.

Rectifiers use a series of diodes, a semiconductor device, to take in the AC charge and redirect the current into one direction of flow. By restricting the flow of power to one direction, the rectifier converts the AC charge into a DC charge the car battery can accept.

How Does An Alternator Work?

While the battery is essential for starting your car when it’s off, the alternator keeps your car alive when the engine is running. The alternator powers most of the car’s electronic components while you’re driving around or idling, including your headlights, electric steering, power windows, windshield wipers, heated seats, dashboard instruments, and radio. The alternator supplies all of them with direct current (DC) energy. Your alternator is also responsible for charging your car battery while driving.

The alternator works by turning mechanical energy into electrical energy. When your engine is on, it powers a drive belt that rests on a pulley attached to the alternator. The pulley turns the alternator’s rotor shaft, which spins a set of magnets inside a coil. These spinning magnets generate alternating current (AC) in the stator, which is then channelled to the alternator’s rectifier. The rectifier converts that AC energy into DC energy, which activates your car’s electrical systems.

Alternators can typically last the lifetime of your vehicle, but that doesn’t always happen. General wear and tear, heat damage, overuse, exposure to water, faulty parts, or frayed wires can put your alternator out of commission before your car heads to the scrap yard.

Warning Signs Of A Bad Alternator

Without a working alternator, your car won’t start in the near future or stay on for more than a few minutes. Yet the typical signs of a bad alternator are often mistaken for problems with the battery or other car parts that display similar symptoms. In other words, if you’re experiencing only one of the issues below, it may be a sign of a bad alternator:

• Dim or overly bright lights
• Your battery is dead
• Slow or malfunctioning accessories
• Trouble starting or frequent stalling
• Growling or whining noises
• Smelling burning rubber or wires
• Lit up battery warning light on dash

A starter motor is an electric motor that turns the engine on when you turn the ignition key. It is a device that rotates (cranks) an internal combustion engine so that the engine can operate under its power. You might be surprised to learn how much more work it takes to get it to crank.

When the engine turns over, it creates suction, which is necessary to get air into the engine. When your engine fails to turn over, it indicates a lack of air intake. Without air, fuel combustion is impossible.

In this reading, we’ll explore what a starter motor is, its function, diagram, parts, types, and how it works.

Let’s get started!

What Is A Starter?

A starter or starter motor is an electrical device that is used to rotate (crank) internal combustion engines so as to initiate the engine’s operation under its own power. As soon as the engine begins to run, it gets disconnected from the engine, which now relies on the combustion process.

The component is mounted on the engine’s gearbox housing, and the starter motor gear meets the flywheel’s teeth. Being an electrical component, a starter consists of a powerful DC (direct current) electric motor and a solenoid. The solenoid receives positive power directly from the battery and heart current from the engine body.

In order to turn the engine, a 12-volt battery must be used to run the starter. This means the battery has to be sufficient to power the device. In most situations where the starter motor clicks but won’t start, the issue is either from the battery or the starter itself.

Function Of A Starter Motor

The primary function of a starter motor in an automobile engine is to start the engine so it can work on its power. This is achieved due to the high torque rotation from the starter motor, which is used to turn the engine at fast speeds. The starter motor gives the engine the first or second rotation it needs to start working on its own.

Parts Of The Starter Motor

There are several components that make up the starter motor. Here are its main parts:

Armature

An armature is an electromagnet component that is mounted on the driveshaft or bearings for a guide. It is made of a laminated soft iron core that is wrapped with numerous conductor loops or windings.

Field Coils

The field coils are held in a housing with screws, as it consists of two or more coils connected in series. These coils receive power from the battery that converts them into an electromagnet that turns the armature. This creates a magnetic field around the armature.

Commutator

A commutator is a section of the shaft at the rear of the housing on which brushes run to conduct electricity. It is made of two plates mounted to the axle of the armature; the plates provide connections for the coil of the electromagnet.

Brushes

Brushes are parts that run on a section of the commutator at the rear of the housing. It rubs the commutator and conducts electricity.

Solenoid

The solenoid features two coils of wire that are wrapped around the core. This solenoid serves as a switch that connects and closes the electrical connection between the starter motor and the vehicle’s battery.

Plunger

The function of a plunger in a starter motor is to push forward so the pinion can be engaged.

Lever Fork

The lever fork is connected to the plunger, which makes them push forward together to engage the pinion.

Pinion

A pinion is a small mechanism containing gear and springs. It engages immediately after the engine starts by extending the gear to the flywheel teeth. The flywheel is the source of engine rotation.

Types of Starter Motor

There are various types of starter motors in a car, each with its own design and function. Here are its main types:

Direct Drive Starter Motor DD

Direct drive is the most common and older type of starter motor available out there. it comes with different applications and construction designs but it’s a solenoid-operated unit. Well, its working remains plain like other types.

When the ignition switch or key is depressed, the car battery energizes the solenoid. This presses the plunger to shift the lever that directs the pinion gear. The pinion gear then meshes with the engine flywheel. So, as the starter motor spin, the flywheel spins along, which then causes the engine’s combustion to run on its own.

Planetary Gear (PLGR)

The existence of these types of starter motors has vastly replaced direct-drive types. It is a permanent magnet that transmits power between the pinion shaft and the armature. The armature spins with more speed and torque. The essence of planetary gear is to reduce gear, which further reduces the requirement of high current.

There is a sun gear located at the end of the armature and three plenary carrier gears inside the ring gear, held stationary. In addition, planetary gears are able to attain a great amount of gear reduction as the ring gear is held and the sun gear is input while outputting the carrier.

Permanent Magnet Gear Reduction (PMGR)

The permanent magnet gear reduction is designed to offer less weight, easy construction, and less heat generation. It features four to six magnet field assemblies rather than field coil starters. It has three terminals on the 12V solenoid and is also heavy-duty, making it require less current. Because there are no field coils, the commutator and brushes transfer current directly to the armature.

Permanent Magnet Direct Drive PMDD

The PMDD types of starter motors are similar to direct drive in several ways. Their difference is that the field coil is replaced with permanent magnets in the permanent magnet direct drive type.

Off-Set Gear Reduction OSGR

These starter motor types work at high speeds at low currents. They are lighter and more compact, which makes them easy to assemble. Off-set gear reduction starters are common among four-wheel-drive vehicles as they increase cranking torque.

Inertial Starter

Inertial starters are the electric types that achieve the features of all types of starter motors. It works perfectly fine during cranking and even ensures the motor part’s safety. It starts the engine strong and very fast, making it the best option for cracking speed. Furthermore, the amount of weight associated with the torque capacity of the starter is extremely minimal.

How A Starter Motor Works

When the ignition key is turned or the button is pressed, the transmission should be in the park or neutral state. The battery voltage goes through the starter control circuit to activate the solenoid. The solenoid powers the starter motor, which aids in pushing the starter gear forward to mesh with the engine flywheel.

This flywheel is mounted on the engine crankshaft, so as the starter motor spins, it turns the flywheel as well as the crankshaft. As soon as the engine starts, the system disengages from the flywheel. Starter motors in an automatic transmission can only be operated when the vehicle is in park or neutral. But in manual transmission, you have to press the clutch pedal.

Inside the starter motor, four field windings are connected to the housing from the inside. The armature (rotating parts) is connected through the carbon brushes in series with the field coils.  However, in some starters, field coils are replaced with magnet fields. There is a small gear at the front of the armature attached with an overrunning clutch.