Skip to content
motorbeast logo
  • Autos
  • Audio
  • Bikes
  • Batteries
  • Detailing
  • Oils
  • Parts
  • Questions
  • Roof Boxes
  • Scanners

Does an Alternator Need Power to Work?

Written BySteve Riley Updated on29/07/2022

Does an Alternator Need Power to Work?It’s not immediately obvious why the alternator shouldn’t power up…

does-an-alternator-need-power-to-work

Does an Alternator Need Power to Work?

It’s not immediately obvious why the alternator shouldn’t power up without having to ignite your vehicle, but on closer inspection of the internal workings of the automotive mechanical system, it’s quite clear that, given enough time, it can’t work without it.

Table of Contents
  • Does an Alternator Need Power to Work?
  • How it works
  • So, does it?
    • Parting
does-an-alternator-need-power-to-work

There is a reason we are advised to keep jumper cables on us at all times when we are on the road. More than it is about preparing for the worst, the concern is supported by the underlying physics of vehicles.

If you have a vehicle, you may think that the battery powers the electrics in your car, but that’s not the case. The battery provides electricity needed for the starter motor to start the car.

When the car is running, the alternator generates energy to feed the electrical system and charge the battery. The alternator used to be called a generator, and it works in a similar way.

In this case, a car’s internal combustion engine spins pulleys under the bonnet, which turns the pulley on the alternator and creates energy.

How it works

An alternator works together with the battery to supply power for the electrical components of the vehicle. The output of an alternator is direct current (DC).

When the alternator pulley is rotated, alternating current (AC) passes through a magnetic field and an electrical current is generated. This is then converted to DC via the rectifier.

Advancements in technology have meant that alternators have changed vastly in the last 50 years. Originally, alternators were only used to generate current which was controlled by an external regulator.

The introduction of a built in regulator, in the 1990s, used the warning light to excite the alternator and start the charging process.

Many modern vehicles adopted a load request type charging system with the introduction of smart charge systems and CANBUS systems which are now widely being used. These systems are controlled by the vehicle Engine Control Unit (ECU).

As the vehicle demands more load the ECU sends a signal to the alternator requesting it to start charging. The alternator has to cope with varying electrical loads and adjust its charge rate accordingly.

This alternator rotor is driven by constant speed drive and this drive gets mechanical power from gas turbine engine, the

refore it only follow that said alternator does require a power but mechanical. Regarding speed control, if alternator is designed for constant frequency power out put obviously it has to be driven at constant speed.

Old version AC generator that has built in DC motor/AC generator motor part being common, part of it is an armature with commutator segments for motor function and the other part is rotating field for alternator function, the DC supply is given through slip rings to produce rotating field and AC output is derived from stator winding of that alternator section.

It is understood that in order to derive out put from a machine power is essential for the rotor to rotate either mechanical or electrical .

So, does it?

Yes—and no. But really, yes. The alternator (most, anyway) does not have permanent magnets as part of its field magnets (stator). The field magnets are electromagnets, so need some “juice” to produce a magnetic field, through which the armature can move to produce electricity.

If you had an alternator attached to a totally dead battery, and spun the alternator, it would not charge the battery. If the battery has a slight charge, or you jump start the car, it will energize the stator enough to get things going.

An alternator cannot ‘sustainably’ generate power without a battery as it uses the back load to generate the electromagnetic field needed in place of the magnets in a generator.

Parting

So the next time you consider testing out whether you can drive without your battery, think again.

Post Views: 22
Post Tags: #Auto Repairs

Related Posts

  • Can you replace a CVT transmission with a regular transmission?
  • Repair Light Car Paint Scratches Using HOME REMEDIES
  • Is Rebuilding a Transmission Worth It?
  • How to fix the CVT Transmission
  • Symptoms of a Bad Torque Converter
electric-car-batteries-how-and-what-next
Yes, Electric Car Batteries are bad for the environment because electric car batteries contain toxic materials, such as lithium and lead, they should not be disposed of like other recyclable materials.
dewalt-vs-craftsman-tools-review-choosing-the-best-toolset
Dewalt Tools Are Worth There WeightThis DWMT72165 vs. DWMT81534 review is...

Car Vacuum Cleaner

SaleBestseller No. 1 ThisWorx Car Vacuum Cleaner - Car Accessories - Small 12V High...
ThisWorx Car Vacuum Cleaner - Car Accessories - Small 12V High...
$29.99
Buy on Amazon Price incl. tax, excl. shipping
SaleBestseller No. 2 Hand Held Vacuuming Cordless Rechargeable-10K PA Strong Suction...
Hand Held Vacuuming Cordless Rechargeable-10K PA Strong Suction...
$39.99
Buy on Amazon Price incl. tax, excl. shipping
Bestseller No. 3 FRESMOL Car Vacuum, Portable Car Vacuum Cleaner High Power...
FRESMOL Car Vacuum, Portable Car Vacuum Cleaner High Power...
$29.99
Buy on Amazon Price incl. tax, excl. shipping

Last update on 2023-02-08 / Affiliate links / Images from Amazon Product Advertising API

the-reliability-of-kia-vehicles
The first time the Kia vehicles were released to the market,...
It can be shocking turning on the ignition only to see...

Affiliate Disclosure

We are an affiliate. We hope you like our recommendations! Just so you know, we may collect a share of sales or other compensation from the links on this website. Thank you for using our links, it helps to grow our website.

  • Privacy Policy
  • Affiliate Disclosure
  • Contact Us
  • About Us
  • Cookie Policy
  • Privacy Statement

© 2023 MotorBeast Motorbeast.Org

Manage your privacy

To provide the best experiences, we and our partners use technologies like cookies to store and/or access device information. Consenting to these technologies will allow us and our partners to process personal data such as browsing behavior or unique IDs on this site. Not consenting or withdrawing consent, may adversely affect certain features and functions.

Click below to consent to the above or make granular choices. Your choices will be applied to this site only. You can change your settings at any time, including withdrawing your consent, by using the toggles on the Cookie Policy, or by clicking on the manage consent button at the bottom of the screen.

Functional Always active
The technical storage or access is strictly necessary for the legitimate purpose of enabling the use of a specific service explicitly requested by the subscriber or user, or for the sole purpose of carrying out the transmission of a communication over an electronic communications network.
Preferences
The technical storage or access is necessary for the legitimate purpose of storing preferences that are not requested by the subscriber or user.
Statistics
The technical storage or access that is used exclusively for statistical purposes. The technical storage or access that is used exclusively for anonymous statistical purposes. Without a subpoena, voluntary compliance on the part of your Internet Service Provider, or additional records from a third party, information stored or retrieved for this purpose alone cannot usually be used to identify you.
Marketing
The technical storage or access is required to create user profiles to send advertising, or to track the user on a website or across several websites for similar marketing purposes.
Statistics

Marketing

Features
Always active

Always active
Manage options Manage services Manage vendors Read more about these purposes
Manage options
{title} {title} {title}
Manage your privacy
To provide the best experiences, we use technologies like cookies to store and/or access device information. Consenting to these technologies will allow us to process data such as browsing behavior or unique IDs on this site. Not consenting or withdrawing consent, may adversely affect certain features and functions.
Functional Always active
The technical storage or access is strictly necessary for the legitimate purpose of enabling the use of a specific service explicitly requested by the subscriber or user, or for the sole purpose of carrying out the transmission of a communication over an electronic communications network.
Preferences
The technical storage or access is necessary for the legitimate purpose of storing preferences that are not requested by the subscriber or user.
Statistics
The technical storage or access that is used exclusively for statistical purposes. The technical storage or access that is used exclusively for anonymous statistical purposes. Without a subpoena, voluntary compliance on the part of your Internet Service Provider, or additional records from a third party, information stored or retrieved for this purpose alone cannot usually be used to identify you.
Marketing
The technical storage or access is required to create user profiles to send advertising, or to track the user on a website or across several websites for similar marketing purposes.
Manage options Manage services Manage vendors Read more about these purposes
Manage options
{title} {title} {title}
Scroll to top
  • Autos
  • Audio
  • Bikes
  • Batteries
  • Detailing
  • Oils
  • Parts
  • Questions
  • Roof Boxes
  • Scanners
Search