# Alternator Replacement



## Driwer (Jun 12, 2011)

Hi, 

I have a question. I have been wondering about that for a while.

Is it possible to take a small electric motor that can work like a generator, I think its a permanent magnet, and use it instead of the alternator in a car. It wouldn't be fitted to the accessory belt, but instead on a chain linked to the drive pullet with a gear.

The car's battery would discharged over time, so there would be a switch in the car changing the engine from generating power to using it by, let's say, unplugging the battery pack or something like that. 

I would just like to know if somebody can tell me if its possible. I am thinking about things like the drive pulley not being strong enough, the motor not generating enough power, or the advantages being null ; Things like that.

Thanks


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## PStechPaul (May 1, 2012)

This has been done before. Here are some links that may help. 
http://www.sigmaautomotive.com/electrocharger/electrocharger.php
http://www.tirereview.com/Article/86808/power_assist_servicing_saturn_vue_hybrids.aspx
http://alternatorconversions.com/
http://en.wikipedia.org/wiki/Integrated_Motor_Assist
http://ls1tech.com/forums/generatio...-doesnt-make-alternator-motor-conversion.html

My idea was to add electric motors to the rear wheels of a FWD car to achieve a sort-of hybrid with 4WD and an emergency backup propuldsion system in case of ICE failure:
http://www.pstech-inc.com/SHAMPAC.htm


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## Driwer (Jun 12, 2011)

I am still wondering though, is it feasible at all? 

Welding a gear to the drive pulley could unbalance it and break it, the electric engine could not generate enough power or use too much, the transmission could not support power being given that way... 

There's a lot of variable


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## PStechPaul (May 1, 2012)

As needed for any new design idea, we must determine exactly what we are seeking, and then work out the best of numerous possible methods to accomplish it. Welding a gear on the pulley might not be the best approach. V-belt drives are simpler and fairly efficient for several horsepower. You may even be able to add a motor/generator using the same pulley and a longer belt, but it seems you would rather replace the existing alternator, so everything could stay the same, mechanically.

Depending on the space you have available, the largest motor you could add would probably be about 5HP. This is probably enough to move a car in a low gear on a mild incline, but it would not contribute very much to the overall performance with a 100HP ICE. If you could attach a pulley to the driveshaft of a rear wheel drive vehicle, you could disengage the ICE and use just the electric motor, or it would contribute directly to the output torque and power with minimal losses. But synchronizing it with the ICE may be a problem.

I don't know exactly what you are trying to do, so please provide more specific details.


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## TigerNut (Dec 18, 2009)

Driwer said:


> I am still wondering though, is it feasible at all?
> 
> Welding a gear to the drive pulley could unbalance it and break it, the electric engine could not generate enough power or use too much, the transmission could not support power being given that way...
> 
> There's a lot of variable


Search on Google, or through some EV equipment dealers (www.go-ev.com), for the EMIS system. They put an electric motor in series with the driveshaft to the rear axle (typically, on a truck application). If a shunt DC, brushless DC, or PMAC motor was used here, you could generate or motor as required.

As far as using an alternator or a PM alternator replacement: A V-belt can transfer something on the order of 2-3 horsepower per sheave, depending on the belt tension. Many older cars used double sheave pulleys on the air conditioner compressor, to transfer enough power to run the compressor without slipping the belt or requiring a lot of tension. The newer multi-groove belts can transfer more power on a single pulley.
For higher power you need to go to a Gilmer (toothed) belt, and these are commonly available and used for ICE timing belt or (in racing) dry-sump oil pump drive applications. You can get high quality pulleys in a variety of diameters, usually in 1" width. A belt like this can transfer 10 horsepower or more, but they're less tolerant of road crap getting between the belt and pulleys.
The extreme would be the 2" and 3" wide Rootes supercharger belts used in high horsepower applications. It typically takes 10% of the engine's output power to run the supercharger (depends on boost); so a 1000 horsepower engine will drive the supercharger through the belt, transferring about 100 horsepower.

Electrically, it can be done. Any torque that the alternator/motor provides to the crankshaft, will show up at the other end; whether or not that is "enough" to justify the added complication depends on your expectations.
Mechanically, anything can be done well, so that it is reliable, or it can be done poorly, and then it will break... welding onto existing shafts or pulleys is one of those 'if you gotta ask, then you shouldn't consider it' things.


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## Driwer (Jun 12, 2011)

Thanks for the answer. It clarified a few points. 

The entire idea, project, is for a physics class. Even if I don't achieve a working vehicule, it's not a problem. I am mostly looking at the difficulty for several idea for the moment. This project is somewhat more interesting due to its link with the actuality, and its possible money saving capacity.

The initial plan was to modify a toyota Tercel by removing the alternator and placing a electric engine there. I was looking at this PM motor with a lot of attention : http://www.hydrogenappliances.com/manta.html . 10hp should be enough to drive through town, and from the plans I looked at, it doesnt seem to be impossible to add to the ICE. As far as the electric system goes, thats all taken care of. My biggest concern is the mechanical connections between the electric motor and ICE, as I posses little knowledge of car mechanics. For all the modification, I have a friend who will gladly help me. All I need is to tell him what to do, hence my questions.

I looked at the IMS, and it is interesting. The thing though is that I can only get a Tercel to thinker and modify. If it all works, I will try adding all that to my Saturn SL1, but thats another time.


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## PStechPaul (May 1, 2012)

I'm a little suspicious of the claims for the Manta motor. See the following:
http://keelynet.com/tilley/tillmanta.htm
http://www.youtube.com/watch?v=qt09AI0IqJA

One of the red flags is the stipulation that the motor temperature must never exceed 125F, or it will be damaged permanently. The motor is rated at 6 HP continuous, and at 90% efficiency that will be 450 watts. That's a lot of heat in a 22 lb package the size of a coffee can. And the temperature under the hood of a car can easily be 125F just sitting in the sun. So that is a "gotcha" that may make it impossible to extract the actual amount of power advertised for any useful period of time.

There is virtually no evidence of any unbiased testing and evaluation of this motor. I found some more realistic data on the Etek motor:
http://www.kellycontroller.com/mars-3001etek-comparable-pmsmbldc-motor-p-29.html
http://kellycontroller.com/mot/downloads/48VCW.pdf

Examining the graph, it appears that the stated efficiency of 90% is not even borne out by the graph, which peaks at 82%. Moreover, the output power over input volt-amps shows more like 73% at best, and 58% at maximum (180%). This motor is also 26 pounds.

OTOH, here is a three phase induction motor, rated 2HP at 400Hz, which is only 3.28"D x 4.25"L. 
http://www.slmti.com/inm/inm.asp?product=INM-33-8A3-00

Of course, a standard three phase motor would be much larger, but they can be overclocked to a point, and there are other motors that might have more believable specs.


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## Driwer (Jun 12, 2011)

After some research, I am down to the manta one, which I really dont like, and those here, which require controllers, which again, I dont like. What would you recommend on this matter?


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## ruckus (Apr 15, 2009)

Yes it is possible.

I am currently developing a system to convert any car to hybrid by replacing the alternator with a motor that also does regen. I have the system designed and am currently sourcing components. 

If you want more details please pm me.


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## PStechPaul (May 1, 2012)

You've probably seen this. It was supposed to be available in 2009 and the inventor is still "almost ready". It's a driveshaft mod:
http://www.sigmaautomotive.com/electrocharger/electrocharger.php

The Saturn Vue was a "mild hybrid" similar to this, but it was essentially a failure:
http://www.underhoodservice.com/Article/62180/power_assist_servicing_saturn_vue_hybrids.aspx

Some more discussion:
http://www.eetimes.com/design/autom...nic-starter-alternators-power-hybrid-vehicles

You might also check out this guy's electric Saturn project, apparently using the Manta motor, but he says he will need a larger one. He claims it will go 45 MPH and range of 100 miles on maybe 6 batteries. I think he is sadly mistaken and has made some erroneous assumptions:
http://youtu.be/RrIKsCWeP0g


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