What is a Generator? What is an Alternator?

[@tadonplane8265]

Any device that generates an electrical current is a generator. "Generator" is a generic term. A photovoltaic solar panel is a generator and it produces DC. All practical electromechanical rotating machines generate AC. The "generator" in a 1951 six volt De Soto is actually a dynamo, that's not an out of date old fashioned term. It generates AC power that is rectified by the commutator and brushes that are internally timed like the valves in an engine. Each time the magnetic field reverses, the commutator reverses the electrical connection for that pole piece. So the dynamo doesn't generate DC, it rectifies the AC it's generating. No modern portable generator has a dynamo in it. Regardless of size they all have alternators. The generators in utility grid power plants are three phase alternators. The alternator in your motorcycle, outboard motor and electric start lawn mower are permanent magnet alternators. The magnets (rotor) are the field. Automotive alternators have no magnets. They use battery excited electromagnetic fields (rotor), fed through small brushes riding on slip rings, which are fed by the voltage regulation circuit. This article missed the most important point of all, silicon semiconductor diode rectifiers. This technology is the reason we don't use dynamos in motor vehicles, small engines or portable generators anymore. Diodes rectify the AC to DC to charge batteries. Automotive alternators are three phase, needing six diodes in a three phase bridge to fully rectify the three phase current they generate. Typically small engine permanent magnetic alternators are single phase requiring four diodes in a full wave bridge rectifier, although there are three phase PM alternators requiring six. The reason dynamos didn't produce enough power at low RPM was because of the brushes and commutator. The brushes are a pair of big carbon resistors in series with the load. Diode rectifiers are much more efficient and never wear out.

[@Timmy-il1hb]

You explained more than the video.

[@tadonplane8265]

@@Timmy-il1hb thanks

[@carbonunit6573]

@@Timmy-il1hboh yeah. 👍

[@gacherumburu9958]

Thanks..👍👍

[@joevignolor4u949]

I think reliability was a big factor. I had an early 1960's vintage car that had a generator in it. I got tired of having the generator rebuilt or replaced all the time so I converted it to an alternator. I never had any more problems with it after that.

[@heronimousbrapson863]

Alternators generally DO require brushes to feed DC excitation current into the rotor windings. The difference is that the brushes make contact with slip rings instead of with a commutator.

[@oz2pe]

Yes !

[@tadonplane8265]

Yes, and the three phase bridge rectifier containing six diodes in a car alternator have nothing to do with voltage regulation. The field is fed by the voltage regulator via pulse width modulation regardless of whether the field windings are the rotor or the stator. In a 1951 6 volt De Soto the PWM was via a stand alone electro mechanical voltage regulator, today it's electronic and may or may not be a stand alone part.

[@danr1920]

My car's alternator has brushes. Also what do lawn mowers use? Showed a picture of one. Magnito? Lawn mowers don't have a battery.

[@tadonplane8265]

@@danr1920 good question. An ignition magneto is different than a permanent magnet alternator, which is also a type of magneto because they're both powered by magnets in the flywheel. In fact the first magnetos invented around 1840 were called magnetos back then but would be called a permanent magnet alternator today. The "magneto" in a Model T Ford is by today's terminology a permanent magnet alternator.

[@oz2pe]

@@danr1920 Many lawnmovers today have electric startmotors

[@philliprobinson7724]

Hi. I owned several British motorcycles from the '50's which had Joe Lucas's 60 watt DC commutated generators. These were married to a cut-out and voltage control box (in an on-again off-again relationship) that gave feedback to the generator's field coils. Voltage control was by vibrating points, energized by electromagnets fighting a spring, the tension of which was adjustable so the voltage output of the armature could be adjusted to the 7.3 or 14.7 volts needed to charge the battery. The unreliability of the system was directly proportional to the number of times you read this paragraph. There was an amp meter on the headlight nacelle. When kicking the bike to life, a huge surge of relief accompanied the amp meter's first twitch that showed the electrics were working today. We motorcyclists traveled in groups, not because we wanted to scare the living daylights out of the locals, but because it was the only way that a few of us would have lights to drive at night. Joseph Lucas was affectionately known as "The Prince of Darkness". Ah, those were the days, but the nights weren't so good. Cheers, P.R.

[@iamterfer]

I can't count how many mates that ride old British bikes have, at one time or another, used the more reliable lights of a Harley to get home at night, many have had to follow a Harley's taillight several times & several have had to do, so many times. Lucas -The Prince of Darkness.

[@philliprobinson7724]

@@iamterfer Hi iamterfer. I'll take your word for it that the Harleys and Indians had more reliable electrics, but let's be self-effacingly honest about this. It wasn't until the Japs, (bless their solid state rectifiers) put alternators on m'cycles, that electrics became so reliable they no longer needed a red "charge warning light" to let you know you had just ten minutes to get home. I always wondered why they used Lucas dynamos? Your average British plonker used a B.T.H. magneto for the spark, British Thomson Houston being an American company. Never had the same trouble with the magneto. I worked in a small M'cycle shop for a time, decarbonizing BSA Bantam two strokes (all my chickens coming home to roost), and learning the magic electrical incantations that kept the AJ's, Beeza's, Matchy's, and Norton's running sweetly, like well boiled icicles. Cheers, P.R.

[@StevenKeipert]

Why do Brits drink their beer warm? They own Lucas refrigerators.

[@philliprobinson7724]

@@StevenKeipert Hi User. I'd love to agree, I really would, but the truth is they weren't so bad at making refrigerators. The first shipment of frozen meat left Dunedin (NZ) in 1882, kept cool by a British steam powered 'fridge unit on a sailing ship (I kid you not.). This "warm beer" thing's got me beat. Any ideas? Cheers, P.R.

[@anvilhead0]

All vehicles used the same system surely. I only read it once, and I don’t remember to many problems with it.

[@bloqk16]

I'm impressed of the disclaimer printed at the bottom of the screen @:12 into the video. That was very thoughtful of the creator(s)/producer(s) of this video. That gives this YT credibility with being forthcoming.

[@jensschroder8214]

Generator is the umbrella term. This includes alternators and DC power generators, like those found in the old VW Beetle. 5:37 The rectifier doesn't regulate anything. The rectifier converts AC to DC. The voltage is regulated via the built-in regulator and the field windings. 6:27 In power plants, the voltage is also regulated via the field windings. It's not just the frequency, i.e. speed, that has to be constant. Also the voltage.

[@ralfbaechle]

In slightly older power plants the frequency is mechanically controlled via the turbine. Once the generator is synchronized and subsequently connected to the grid one could argue that the power grid is controlling the frequency of the generator as the influence of a national grid hooked up to the generator via a high voltage line is stronger than the puny influence of the turbine regulator. At that point opening up the regulator of one generator will only marginally (mHz if that much) influence the frequency of the generator and grid but mostly influence the current being "pumped" into the grid.

[@davidquirk8097]

This video is full of errors.

[@budisutanto5987]

Question 1. Why not use Alternator (DC) then convert it to AC, Instead of: Generator AC + stabilizer, since the result would be 'good' frequency AC ? (for home / factory use) Question 2. If the answer of q1 is higher price, because Alternator require less maintenance, is it worth it ?

[@pauljanssen7594]

Let me put it this way to you about generators and alternators, generators were the first design of 6-volt systems that had to produce more amperage for 12-volt systems which causes extreme load on the armatures. Add idol not efficient to produce enough power, the alternator is a device that can produce high power at all speeds. Since the invention of efficient electrical diode that can turn AC into DC thus we have the efficient alternator.

[@JBK647]

Add idol-

[@WXUZT]

Great way of Explaining ! Thank you for your effort and time !

[@jodymorris1072]

Very good video of the different types of electric generator capabilities.. My Great Grandfather's occupation was being an Electrical Engineer at the turn of the century in the late 1,800s.. He built a Hydro Electric Dynamo for the town of Silverton Colorado.. Then him and his crew built the power system for the town..

[@danburch9989]

I'm from the old school. Generators produce DC power through the commutator; alternators produce AC power through slip rings. The video shows a good explantion of the difference. During the video, the narrator uses the term "generator" to refer to both types of power generation. That push mower uses neither so it shouldn't be in the video. One advantage of a DC generator is that it can be used as a starter motor in small engines until the engine is running. Then it can produce DC power for the needs of motor. Gas golf carts use this method for one.

[@mortsnerd]

AC is NOT produced thru the slip rings, the AC is produced in the stator and the stator is connected to the rectifiers to produce the DC for the vehicle. Slip rings feed a DC voltage to produce the field or excitation, field current from the regulator controls the output via a sense line. Newer ones use PWM and ECM control.

[@Freq412]

FWIW, generators are also used in helicopters to start the turbine engine and then to produce power for the avionics, lights and FADECs. I believe this is also the case for turboprop, turbojet and turbofan jet engines used in airplanes.

[@danburch9989]

@@mortsnerd I stand corrected. I should have worded it differently.

[@eugenekochnieff7055]

WRT automotive generators. Both devices are generators, one is a dynamo, the other is an alternator. They both produce AC current, the difference is how they rectify the AC into DC. The alternator uses semiconductor diodes, and a Dynamo rectifies the AC mechanically using the commutator.

[@timothyhall861]

a Dynamo is desighned to function efficiently as both a generator and a DC motor....The Dynamo on Huey Helicopters functions as it's Back-up Generator AND it's starter motor

[@Dr_Larken]

Man, the comment section! Full of “ why doesn’t it talk about this?” “Um correction, technically…” & “not every.. has..” like, did not one person read the title? It’s a video that is trying to simplify a complex topic, people that aren’t electrical engineers, into cars, a basic or in depth understanding physics!

[@DanielleWhite]

Motorcycles are interesting as the stator and rotor are frequently within the engine case. The exception of ones I have owned was a BMW R1100R where there was an alternator driven by a belt from the crankshaft.

[@asificam1]

AC generators like those at power plants do not have a commutator, they may have slip rings like an automotive alternator has, but those would be for excitation current like in an automotive alternator. Only DC dynamos have a commutator and that is because all electromagnetic based generators (everything other than a solar cell, battery, etc.) generate AC power, the commutator switches the polarity of the AC so that it becomes a pulsed DC current, doing the same job as the diode pack on a car alternator but with a mechanical device instead. Gas generators probably use an alternator-type design so they can omit strong magnets and use an excitation current instead which also allows for cheaper power regulation without as much need for complex and expensive solid state parts like a LARGE buck boost DC-DC converter or a more complex design for the inverter... and a simple design can be achieved with an AC generator designed like a car alternator by hooking it directly to the plugs and holding the motor at a constant RPM so that the waveform is roughly a 60Hz sine wave. This video is slightly misinformed. Most generators today are alternators, just a LOT bigger and often more efficient than a car alternator.

[@richardhemingway6084]

Why is there no mention of a 'Dynamo'? In use in cars, dynamos generate DC (interrupted) to charge batteries directly. They were replaced with Alternators on cars, only when solid state rectifiers became available (to turn the three phase AC immediately to DC). Alternators then became the default generators of car electrical system, because they can output more power and turn at a faster speed. The commutator of a dynamo, limited it's turning speed and so, at low revs could not produce much power. I found this video uneccessarily, misleading and contradictory. Alternators produce A/C. Dynamos produce D/C and the term geerator encompasses anything that produces electricty by mechanical means. Simple.

[@Secession1900]

Thank you for that explanation. I knew that cars were switched to 12V from 6V at about the same time that alternators came in but never knew why.

[@lCountMike]

Generators that use permanent magnet are generally called "Dynamo". If magnet is in the rotor they produce AC. When magnet is stationary the can produce either AC or DC using commutator. Example are generators for bicycles.

[@BitSmythe]

2:45 *Here is the answer.*

[@sarj743]

Car alternators do indeed have brushes that wear out.

[@josefmazzeo6628]

Some do, some don't - it depends if the rotor is a permanent magnet or a coil wound electromagnet, which in the latter case requires slip rings which wear out.

[@gailsmith9835]

Alternators with a permanent magnet do not require a slip ring to control the field . However use a zener diode to for control.

[@ve2zzz]

Virtually ALL gas/diesel powered generators, along with all large/giant power plants use inner rotary field and outer stationary armature windings to produce AC power.

[@pecilijevelicanstveni4973]

Read answer from @majed9r! Alternators have brushes and slip rings to maintain the magnetic field in the rotor. As the speed of a motor is changing and the power needed for the equipment (headlights, stereo etc.) is constantly changing, one current regulator is needed to maintain the constant voltage between 13.7 to 14.5 volts to fill the battery. This regulator regulates the current through the slip rings. The output is 3 phase AC those who are rectified to DC. And to be precise: every machine that generates (converts) one type of energy to the other is generator. The usually term generator is used for the conversion to electrical energy, usually mechanical energy. (Solar generators? Convert Sun energy to electrical).

[@jensschroder8214]

Lawn mowers have neither a generator nor an alternator that feeds a battery. Lawn mowers and small engines have a magneto ignition that only produces the spark.

[@thedarkknight4243]

True

[@stevenkroot31]

Some lawn mowers do have “generators”, some electric start lawn mowers proved a small changing voltage to maintain the charge on the battery (some don’t provide a charging voltage, the owner has to periodically connect a charger which is kind of dumb in my opinion.) The charging circuit for the lawn mower battery is very basic, just a separate coil that picks up the magnetic field primarily intended for the ignition magneto, a single diode provides half-wave rectification (only allows the positive part of the alternating current to pass) and blocks the battery voltage from discharging through the coil. It is very inefficient (cheap) and completely unregulated, typically the batteries don’t last more than one or 2 seasons because the a constantly being overcharged.

[@brianperkins6121]

If the lawn mower has a battery operated starting system it is an option to include a charging coil or more correctly a stator , as the flywheel with its integrated magnets spin past the coils of wire within the stator, an Alternating Ac current is produced in proportion to the speed of the engine , because the intension is to charge a Battery this must be put through a rectifier turining the output in DC current this device also contains a regulator to prevent overvoltage at high rpm as well as regulate the charging process, in this case the regulator ususly shrunts the excess currrnt through a series of resistors to control the charging currrent and voltage supplyed to the battery. some newer regulators use transistors to regulate the volatge coming from the stator as the AC sine wave goes through them they cut of the top of the sinewave to hold the voltage below a given level this has the avantage of not producing so much heat. I have seen a few very cheap few systems that simply have such a small stator that is put through a half wave retifier that produce such low charging currents (under a half an amp) that they exclude the regulator kzbin.info/www/bejne/fpXMappsq5qnaLM

[@jeffgriffith7003]

Pretty much all riding mowers and commercial mowers with electric start have an alternator built-in underneath the flywheel. Smaller push mowers generally do not.

[@timothyhall861]

Motorcycles and some lawnmowers have an extra winding on the magneto to charge their small batteries

[@rscgln]

The correct title of this video should be "Dynamo vs Alternator". "Generator vs Alternator" is like "Vehicle vs Car" or "Animal vs Cat"!

[@lokesh303101]

Generator gives the Direct Voltage. Alternator gives the Alternating Current by Amplifications.

[@grahamcrooks3581]

You forgot to mention one really important difference between ac alternators, [which need and exiter current to start them] and the old fashioned generators, which did not. But the other difference in practise is that the alternator can produce power at idle.

[@PhysicsbyAtif]

One more thing is that, the generator does not fall into simple thing category.

[@carbonunit6573]

Is there going to be a test after this?

[@AlainHubert]

Very interesting. Thanks for sharing. One question: who is the narrator for this video, he did a superb job, and his voice seems familiar to me for some reason? He sounds a bit like Jerry Sanders (founder of AMD), but it can't be him, can it?

[@cancel1913]

I did enjoy this narrator's voice and cadence speaking.

[@cameronl62]

I'm pretty sure it's computer generated.

[@AlainHubert]

@@cameronl62 If it is, it has come a long way from the early attempts. I used to be able to easily tell when it wasn't a human, but nowadays it's sometimes surprisingly good. I guess this AI-generated narration was modeled after Jerry Sanders's voice maybe? 😆

[@ojofelixnm3608]

Fixed conductors and a rotating field. I remember an individual who didn't understand the alternator design and replaced it with a generator.

[@gailsmith9835]

Alternators use rectifiers to convert ac. To. Dc. Diode rectifiers have a forward voltage drop due to internal resistance.so they burn some current up as heat.brushes have very little loss. Possibly more efficient.

[@oml81mm]

A magneto also could be classed as a "generator", although a somewhat specialised one.

[@josephpacchetti5997]

Excellent Video. subscribed.👍

[@fritzeder1847]

Today, all commercial generators are synchron or asynchron brushless AC machines.

[@jameshoffman552]

6:44 “Every car on the road today… has an alternator” My Model Y doesn’t, and it’s the best selling car in the world.

[@kamdala]

Model 3 Highland 🫣

[@SuperDeni13]

The alternators do has a brus which use to feed the rotor coils to create a magnetic fields, the alternator voltage regulations doesn't done with brige diode rectifier at the output stages, it regulated the voltage by regulated the rotor magnetic fields which differ according to the rotor rotation speend

[@samable9585]

why then big turbines don't use Alternators?

[@LarrySong712]

correct me if im wrong I often take that generator is the general name for mechanical>electrical conversation component alternator is specific to be called where alternating current is generated as its first form after energy conversion, or easily called AC generator. for direct current, we can call it DC generator or specifically Dynamo. maybe in the future DC gen will be call Direct-or? 😂

[@gailsmith9835]

Silicon diodes used in alternators i would not refer a simple thing. It is possible to make every part to a generator in a basic machine shop. Not so to make a replacement diode rectifier.

[@claybair4904]

I have worked on machines when very many of them had generators . I have worked on cars and tractors since the 60s to now and have not seen an alternator with out brushes . They use contact rings or slip rings instead of a commutator . Maybe they now have a brushless alternator , that is news to me .

[@thedarkknight4243]

Great information

[@davidfalconer8913]

In the UK , the ( older , 1960's automotive ) DC generator , that did the same job as a modern alternator is specifically called a DYNAMO ... these produce less power than modern alternators ! ! ..... DAVE™ 🛑

[@lemongavine]

Not every car on the road has an alternator…..electric vehicles don’t. They have a DC to DC converter to run the accessories off of the high voltage traction battery

[@calebflix6123]

I boycotted many physics classes back there in school but one thing I know Current is induced in conductor when it experiences change in magnetic flux and not magnetic field😂😂

[@stephenbrickwood1602]

ICE motor throttle can maintain constant speed for the generator.

[@SB-sp7zf]

Generators generally transmit power through the brushes

[@primonda56]

Does the generator's winding as shown in this video can overheat like alternator's when overloaded? I noticed alternator's winding are stationary thus lesser cooling compared to the generator?

[@dontosaw]

Correction, some hybrid vehicles don't have an alternator. The 12 volt accessory battery is charged via a DC to DC converter that steps down the high voltage from the traction battery to a voltage suitable for charging the 12 volt battery (about 14 volts).

[@andretorben9995]

A generator only creates low voltage (less than 24 volts), DC power. An alternator creates both AC and DC depending on how its connected. Thats why its called an "alternator", it has alternative power generation.

[@ferozenoordeen3711]

What about the external mechanical power, that needs 0to activate these devices....?

[@gailsmith9835]

You did not mention a true generator can generate dc without external excitation due to residual magnetism. Therefore a generaror can be push started and will provide power for ignition to start an engine.

[@palashchoudhury5565]

Use Alternator in Power Plant due 2 its Efficiency & Less Voltage Fluctuation whch ll increase Grid Stability Btw we nvr Generate DC Power

[@JanwarKali]

Number of turns

[@billmoran3219]

Gee I’ve probably rebuilt a thousand alternators, if I remember right they all had brushes?

[@colinz226]

All alternators are generators. An alternator is more efficient than a DC generator. Just get some diodes and capacitors and resistors and you can rectify the current!

[@hotstonemedia376]

Generator & Alternator vs Dinamo when it comes to having brushes or not.

[@heinritske8256]

Dynamo?

[@sneaky_krait7271]

Interesting, I thought car alternators were 12 volt DC motors. Why is an AC motor with rectifier used?

[@slebetman]

Should have included magnetos

[@agzabatmd]

Where do dynamos come in? I remember having one in my bicycle.

[@rscgln]

Curiously, the so called "Dynamo" in bicycles was a permanent magnet *alternator*! A Dynamo is a generator that produces DC output through collector and brushes that weren't present in bicycle "Dynamos"!

[@richardwallinger1683]

prince of darkness.. memories .

[@ivekuukkeli2156]

3. type is aggregator. How it differs?

[@dwightelvey645]

This was the most bull I've ever heard. Most small portable generators work just like the alternator in your car. The main difference is that in a true generator the power id feed through the brushes. In an alternator the field is powered through the brushes. The fact that the generator has the power going through the brushes and that if DC is desired, this is done through a segmented commutator. This was done because high current diodes were not yet invented. Both can be used to create AC or DC outputs but the rotating field winding makes more sense with solid state regulation. The old DC generator used in old cars use a regulator that controlled the output that wasn't solid state. It used a relay like device that measured the strength of the magnetic field and changed the field current by chopping the current to the field winding. The small portable generators use the rotating field windings. ( smaller that 10KW typical ) larger generation usually uses fixed field windings because the cost of the higher current in the external windings needs to be larger, as compared to the smaller amount of copper needed for the field. It is true that brushes that carry higher current through a commutator have more arcing and wear faster. Still, the brushes in alternators do wear. In my experience warn out brushes are the most common failure of car alternators that are no abused. Bushes are cheap compared to the complete alternator but shops have different warranty than a home mechanic ( 1/10th ). When someone tells me, that their alternator just died, the first question I ask, is did they jump start another car within the last month or so? If so, that was likely the cause. The older generators can take sudden high current loads required for starter motors and can take more abuse. The diodes in alternators can be damaged by such sudden high current loads. When I jump start, I ask for the other car's keys. I charge their battery for a while with my engine then shut my engine off and give them back their keys to try to start. I do use home made cables with 00 wire. I can even start a car without a battery with my cables. Never use your alternator to power a starter! Even if it seems to work for a few weeks, the high current through the diodes can rupture the hermetic seal. Moisture and other contamination will cause the diode to fail being a diode.

[@Daniel-79]

Today I learned that an alternator produces a consistent voltage across a wide range of engine RPM. Additionally, generators offer versatility producing both AC and DC power

[@michelgrenier1878]

A pure dc generator with a commutator likely produces power at a much lower cost as the flow of electricity does not alternate .

[@janami-dharmam]

why and how?

[@ooltimu]

​@@janami-dharmamthe commutator acts like a mechanical rectifier bridge

[@janami-dharmam]

@@ooltimu Not quite correct; read and you will learn. A rectifier bridge is a output only device but a commutator is mostly a input only device.

[@ooltimu]

@@janami-dharmam sorry, but that is garbage and makes no sense. A rectifier bridge has both an input and an output so that it can get AC in and rectify it so it will output DC. The commutator serves the same role, but it is mechanical. Search on google, wiki etc.

[@user-GALVATRON]

Generator has gener and alternator has altern this is the difference, I know until i saw this video

[@grahamearley1820]

I have been told Alternators only maintain a battery, and that they dont charge up a battery, true or false?

[@billmoran3219]

Check your battery voltage after the car has been running for a while, you may see almost 13 v on a 12 v battery, then turn in your lights for a minute then off and recheck battery voltage, it will probably read about 12.6 v, you just removed the surface charge.

[@grahamearley1820]

@@billmoran3219 thanks for the reply, but what i was get at was, a near flat battery will remain in that state, if charged by an Alternater only, meaning it will be maintained at that level and will never be fully charged up, and willl die quicker.

[@didierdel2319]

Pourquoi justement, on n'installe pas un alternateur pour recharger les voitures électriques ?

[@ibmibm691]

Electrical machines

[@Ray_of_Light62]

Dynamo and alternator are two different types of generators.

[@estamnar6092]

dc = generator ac = alternator ez

[@67daltonknox]

I well remember the days of dynamos, distributors and points... awful things. My knowledge did help me one time to bail out some fellow tourists in Mexico. Their VW Vanagon wouldn't start. Recently serviced, the lock screw on the points had not been tightened enough, so they had opened too far to make contact.

[@henrivanbemmel]

Faraday's deals with the changing magnetic Flux. This can achieved by varying the ambient B field and/or position of the detector. You claim only that its the changing B field tet in your Faraday's Law cartoon the B field of the inserted magnet is unchanging, but the local Flux experienced by the child changes with the position and thus motion of the magnet.

[@martindennehy3030]

Alternators are generators. Generators that produce AC. Generators that produce DC are called dynamos.

[@archmcdonald6170]

Generators produce DC, Alternators produce AC

[@grantmoon624]

The main winding was of the normal lotus- o-delta type placed in panendermic semiboloid solts in the stator…

[@TheBMURPH2012]

I’ve never seen a car that runs on AC power… You can tell they used AI to make this video.

[@chrystineleibel608]

Ever hear of a bridge rectifier.