Car Alternator to Cheap Motor

Hi,

This is my first instructables.

Because of my English i put more pictures and less words.

In this instructable i will try to explain how to convert car alternator to motor.

Step 1: Material Required

You will need:

- old car alternator

- servo tester

- Brushless ESC speed contorler

- 12V Battery

- 5V Power supply (old PC supply or some DC step-down)

Step 2: Disassembling

This is Bosch alternator from German cars in 1980.

First disassembl regler (two screws).

Then unscrew 4 screws from front (pulley) side.

After separating Stator and Rotor remove stator and diodes from housing (3 screws).

Cut off diodes from stator.

Step 3: Modifications

Isolate brushes.
I made this with angel grinder.
And solder some wires on both brush.

Step 4: Wiring and Assembling

I use PC power supply 5V for rotor, and car battery 12V for ESC (stator).

You can also use 12V on rotor, but motor will bi slow and spent 3 amps on rotor.

After wiring assemble everything back except diodes.
Some better ESC have switch for changing direction, but you can do manually switching two phase.

And that is all.

And one more think.

Please be careful, this is a powerful
motor and it can hurt you.

Comments

[ChadH14]

Detailed instruction on the wiring would be nice. Have all the parts, but not sure what to do with them. Thanks.

[ChadH14]

I'm clearly missing out on something. Where do the 2 (new) wires from the isolated brushes end up going? What are they wire into? Thanks.

[efiyulianti1777]

Tq my bro, I try again sun after see your Vidio, becouse I Haven try 3 or 4 but not succes until now...of I try working or not I try to give you know 9kay tq

[degohn]

Hi, is there any way to run this motor without esc or servo tester because I can't get them? will this require to adjust winding type of the stator? thank you for reply.

[MthokozisiN1]

Hello, thank you so much. I managed to make the conversion but I was wondering if i can increase the power/torque by increasing the field voltage or current or increase the stator voltage to say 15 - 18 vdc as I'm using a 2-6s 30A esc.

[Angelo Inferno]

Increasing stator voltage would be ideal, increasing the rotor voltage too high will reach saturation in which case you start increasing heat without any measurable increase in performance. Ideally, if you don't want to find a way to adjust back emf by modulating rotor voltage, it's good to just use about 5 volts into the rotor for general purpose, then adjust with a bench power supply while testing in various scenarios/uses until you find what works best for you applications.

[HarryH49]

Hello, have you considered to replace the rotor coil with permanent neodymium magnets ?

[ivosusak]

Hi Harry,
Well, on rotor coil i adjust torque and speed.
Permanent neodymium magnets are excellent idea if we use alternator like alternator.
In that case we do not need power supply to start generate current.

[Angelo Inferno]

A permanent magnet would give two benefits, one would be to reduce wear as the slip rings are no longer needed, and the other being to increase efficiency as no field voltage is needed. The downsides are that the project is more expensive now, and as ivosusak stated the rotor field can be adjusted based on rpm and torque by modulating back emf.

[1uglyman]

I'm trying your experiment. My alternator has 4 wires,1 ground / neutral ( I believe).
What would I do with the 4th wire?
Thanks

[Angelo Inferno]

Basically just stick some shrink wrap or other insulation on it and ignore it

[PS118]

Think of an alternator as three different phases. (3 coils)


They can either be wired in delta or y (what the author calls "star") configuration. In the y configuration, you can have a fourth wire, which is the common center point. In an ideal world this should be 0 volts and is a no-connect.

You'll need to use a multimeter to find out which one that is. The common point node should both:

1) Have the least resistance to any other wire.
2) Have the same resistance to all other wires.

From there, the controller is smart enough to tell the difference.

More info:

http://modelaviation.com/inside-esc

[DIY Hacks and How Tos]

Interesting idea. I wonder you much power you can get out of it.

[Angelo Inferno]

Your average alternator runs well at 36v and can typically drive at least 2100 watts at the output shaft (2.8 horsepower, this is assuming a small 85 amp alternator and 70% efficiency). Many if not most alternators are rated at 100+ amps so can typically get even larger power ratings. If you can program a controller and wire it up with a strong understanding of your alternators design, you can modulate the voltage/amperage to the rotor field windings and get potentially much much more power out of it, back emf directly relates to rpm at a given stator voltage, so adjusting that voltage based on rpm to give more torque at lower rpm and less amps at higher rpm would allow you to use a broader range of voltage and amps on the input leading to higher overall power, but that's a story for another day.

[hobbyman]

I've read about people getting 1000W or more power from alternators modded like this. This is really a good idea for obtaining cheap motors for electric motorbike conversions.

[ivosusak]

In idle speed consume 1,6 amps.

When i put some load, speed little decrease and it can consume up 10 amps.

Probably more, but my ampere meter can measure max 10 amps.

[Al AmineB]

Hello I don't know how to isoleate the brushes and remove links , can someone please explain in detail , or show image please

[Angelo Inferno]

The method largely depends on the alternator in question. Many alternators have different methods of connecting the internal brushes and so that question can't be answered without seeing what's inside your alternator. If you can post a pic of the alternator you have disassembled then maybe someone could help more.

[ShararrA]

Hey, hows the max speed . does it have enough torque to run a bicycle . can i run it on more voltage

[Angelo Inferno]

Speed depends on volts and gear ratio, torque depends on amps and gear ratio. Mechanically speaking an alternator should be capable of at least 6,000 rpm. The amps (so long as your power supply is capable enough) is determined by your controller (they are each rated for a certain amount of amps before heat becomes an issue). There are two different voltages that affect your speed, first is field voltage applied to the rotor and the second is the voltage applied to the stator (voltage coming from the esc). The higher
your stator voltage the higher your rpm, the lower your stator voltage the lower your rpm. The higher your rotor voltage the higher your back emf is, the lower the rotor voltage the lower your back emf.