# converting a starter motor



## onegreenev (May 18, 2012)

I'd go with an older Generator instead of the starter. They are designed to run all the time unlike the starter which is designed to run for seconds at a time.


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## dougingraham (Jul 26, 2011)

johnsiddle said:


> Just a hypothetical question,
> 
> If a starter motor could be fitted with high speed ball bearings could it be used as an ev motor?????
> Or what is the factors stopping one of these motors from being used apart from ventilation.???
> john


They are too small to power a car with. You could probably motivate a bicycle with one. They are not very efficient motors. They don't have to be for their intended application. You run them for a few seconds at most a few times per day.


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## dragonsgate (May 19, 2012)

Out of necessity I pulled a pulled a 70 Toyota Land Cruiser hooked to a 16ft camp trailer up a slight incline for a little over an eighth of a mile on the starter once. The total weight was over 5,000 pounds. It was a heavy-duty four post GM starter. A few years ago I got to thinking about that and machined end plates to hold bearings for a small fiat starter. I never applied it to anything but it worked pretty good on the bench. If you have time on your hands and like experimenting go for it. You might consider Onegreenev’s suggestion of an old automotive generator if you can find one much less one that works or is rebuildable.


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## Woodsmith (Jun 5, 2008)

I'm wondering what John's project is....

Maybe there is a better alternative small motor available, somewhere.



However, an old dynamo/DC generator would already have the bearings in place and be designed to run continuously.


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## johnsiddle (Jun 22, 2011)

Two or three reasons for asking.

1, they are designed for high current (although not hi speed).

2, they are cheap and there is a lot of them about.

3, I like tinkering.

4, I have an old 250cc Kawasaki 3 cylinder motorcycle in storage (been there for about 15yrs) which might just lend its self to electrifying...

I haven't seen too many dynamo's around for years and I do keep thinking about alternators but not sure what they could produce...


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## johnsiddle (Jun 22, 2011)

dragonsgate said:


> Out of necessity I pulled a pulled a 70 Toyota Land Cruiser hooked to a 16ft camp trailer up a slight incline for a little over an eighth of a mile on the starter once. The total weight was over 5,000 pounds. It was a heavy-duty four post GM starter. A few years ago I got to thinking about that and machined end plates to hold bearings for a small fiat starter. I never applied it to anything but it worked pretty good on the bench. If you have time on your hands and like experimenting go for it. You might consider Onegreenev’s suggestion of an old automotive generator if you can find one much less one that works or is rebuildable.


I think this proves my point that they might be useful, I know the gearing is low but still I bet the current was massive.


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## johnsiddle (Jun 22, 2011)

onegreenev said:


> I'd go with an older Generator instead of the starter. They are designed to run all the time unlike the starter which is designed to run for seconds at a time.


I also considered these a good idea but not sure of the power they could produce, I assume you are talking about AC alternators rather than DC Dynamo's.

John


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## johnsiddle (Jun 22, 2011)

dougingraham said:


> They are too small to power a car with. You could probably motivate a bicycle with one. They are not very efficient motors. They don't have to be for their intended application. You run them for a few seconds at most a few times per day.


They could pull 500amps at 12v which would give 6kw about 8hp, I know the batteries wouldn't last very long, but maybe at 48v or a bit higher things might be better. Their brushes and comms can certainly handle current.

Construction wise they are not too dis-similar to modern drive motors, bearings, armature binding and cooling seem to be the main ones.

Its still a hypothetical question at the moment..


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## major (Apr 4, 2008)

johnsiddle said:


> They could pull 500amps at 12v which would give 6kw about 8hp, I know the batteries wouldn't last very long, but maybe at 48v or a bit higher things might be better. Their brushes and comms can certainly handle current.
> 
> Construction wise they are not too dis-similar to modern drive motors, bearings, armature binding and cooling seem to be the main ones.
> 
> Its still a hypothetical question at the moment..


Realistic maximum power from a cranking motor running from a 12V car battery is more likely less than 3 hp. 500A * 8V * 50%. The motor is built for torque, not efficiency. It is also built for short infrequent duty and will not run continuously for more than a few minutes without overheat. The brushes are loaded with metal for low voltage drop and therefore would not tolerate higher voltage. They will also wear out quickly when in prolonged use. The motor is grounded.

Although at a glance the cranking motor may look like a mini-Warp9, it is quite different.

major


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## dragonsgate (May 19, 2012)

I was not suggesting putting a starter motor in a full sized car. My project was to use one for a wench motor on my car carrier. There are some web sites about using starters on go karts.


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## major (Apr 4, 2008)

dragonsgate said:


> I was not suggesting putting a starter motor in a full sized car. My project was to use one for a wench motor on my car carrier. There are some web sites about using starters on go karts.


Actually winch and intermittent duty pump motors are adaptations of the basic cranking motor design. High torque, low efficiency, low cost, low duty cycle. 

I had one on a mini bike years ago. A single 12V battery and solenoid. It was terrible, but kinda fun. Motor would get real hot in a short while. Especially the rear bushing near the comm.


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## johnsiddle (Jun 22, 2011)

major said:


> Realistic maximum power from a cranking motor running from a 12V car battery is more likely less than 3 hp. 500A * 8V * 50%. The motor is built for torque, not efficiency. It is also built for short infrequent duty and will not run continuously for more than a few minutes without overheat. The brushes are loaded with metal for low voltage drop and therefore would not tolerate higher voltage. They will also wear out quickly when in prolonged use. The motor is grounded.
> 
> Although at a glance the cranking motor may look like a mini-Warp9, it is quite different.
> 
> major


Thanks for your reply.
I did say that cooling would be a problem, the brushes could be replaced with heavy duty carbon types.
I take your point about the output power, I was using just basic figures to show the initial potential of the motor and its bits.
Being grounded would be a problem unless the controller was designed with this in mind, not an insurmountable problem.

It just seems a pity to me that all that untapped power is lying around in scrapyards unloved.

I must add that I was thinking more of the old starters with their long shafts and bendix gears rather than the newer smaller ones with the built preselect gear.

I can see how the sleeve bearings would suffer fairly quickly hence the possible fitting of ball races.


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## shortbus (Sep 27, 2011)

Some Saturn cars had a dual duty alternator. In one mode it was the starter. After the ICE was running, it switched over to being the alternator. These units are expensive in a bone yard though.

http://en.wikipedia.org/wiki/BAS_Hybrid


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## johnsiddle (Jun 22, 2011)

shortbus said:


> Some Saturn cars had a dual duty alternator. In one mode it was the starter. After the ICE was running, it switched over to being the alternator. These units are expensive in a bone yard though.
> 
> http://en.wikipedia.org/wiki/BAS_Hybrid


Never seen these....


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## feloni (Nov 17, 2015)

Hello mr. JohnSiddle,

I knew the site: http://www.diyelectriccar.com as few now and become a member of it, for I have seen your topic on Google on a subject that is of interest to me.

As the topic stopped at 07-2013, I did not take many conclusions about the possibility of using a starter on a common e-bike, "made at home".

I saw some videos on Youtube bikes with starter, Animated me and I'll see if modify a Bosch starter of a car of my "trash" country, is simple model for a 4-cylinder engine of GM.
In Google also found on one page of a person who teaches you how to modify a starter almost the same as I bought, to use a PWM circuit.

Many people say that a starting motor can not be used in other vehicles and it was only designed to work for short periods, etc.

But I thought I'd change it (starter), removing the solenoid (automatic as it is known here) and Bendix and everywhere ratchet engagement engine/starter, "muzzle" is known here
I think of adapting two bearings to replace the bronze bushings to support the rotor (armadure)
Only these changes I think ja improve the project as it would leave "lighter", as well as make some holes on the cover of brushes for increased ventilation.

Due to good power of the starter, I would move easily a bike and would not be necessary to continually triggers it, just to give impulse to bike on the straights and mostly uphill, that is the most important.

I ask him if mr. he went ahead with his starter project to bike or not?
And if you (or forum friends) know of someone who uses a starter on a bike electric or website, etc dealing exclusively on this subject, I ask you please to communicate.

Very thanh you to all.
Best regards, 

OSWALDO FELLONI
(From Brazil)

Sorry for bad inglish, but is fault of Google translator.


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## Michael Picious Mukupa (Nov 6, 2020)

_*What of blowing into the starter motor(i.e. drilling inlet & outlet holes) air cold enough to cool down the starter... Can't this make it run continually?.. I guess so...*_


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## johnsiddle (Jun 22, 2011)

Michael Picious Mukupa said:


> _*What of blowing into the starter motor(i.e. drilling inlet & outlet holes) air cold enough to cool down the starter... Can't this make it run continually?.. I guess so...*_


Its what I am doing on forklift hydraulic motor. Its not back on the road yet so dont know how efficient it is.


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