Alternator powered drift trike

[jlake]

Hello all, just found this forum and looking at some of the projects on here makes ours look a bit basic.
My son wants to build a electric powered drift trike, in other words he wants me to do most of the work and then buy all the bits !
But seems like an interesting little project that we will both learn from as we go.

This is the very beginning.
So first thing is the alternator I have in the garage, and we want to determine the (ball park) power consumption / power output once its converted to a motor

Its a 115A unit, so assumption is that at, 12V 1380w, 24V 2760w, 48V 5520w, does this sound right, anyone know of a link where I can get a bit more info ?

Once I know the motor power I can work out what batteries and controller we will need.

Thanks


Jack.

 

[amberwolf]

LIkely you won't be able to determine the actual power capability until you actually convert it into an altermotor, and have it operating in the system, and begin pushing it's limits till it heats up more than you want it to. It also depends on the RPM youll use it at vs the torque you're getting out of it (power = torque x rpm), so if you're spinning it slowly you can't get as much power as if you spin it fast. They're meant for ridiculously high RPMs on the engine belt system, in the original application--that's how small motors make big power (and by moving lots of air past them all the time). How fast are you going to spin it, and how are you going to cool it?

If you haven't already looked around at any of this, there is quite a bit of information at various pages in this list:
https://www.google.com/search?q=altermotor
but it is a lot of reading, and I do not know if it has the info you are after in an easy-to-find-or-use way. :/

 

[jlake]

Thank you for reply,

Had a quick look at the link you put up, may need to read that a few times to soak it up.
At this point I know nothing about motors, I know so little I don't know what I don't know yet, but I have gathered that alternator motors need to spin fast to make power.
How fast am I going to spin it ? Don't know but at 5000 rpm on 10" 797mm radius kart wheels with 1:5 gearing makes 48 KpH which is fast enough.
Cooling can be via the fan attached to the front of the unit. Maybe!
We have some RC lipo batteries and controller which can be put on to this motor just to see what happens first.

Any more info or suggestions are welcome

Jack.

 

[enrengineering]

I used a 140 amp car alternator to electrify my go-kart for a university project, it worked well until I pushed it. I achieved a top speed of 41km/h with a 3:1 gear ratio. The list of problems: overheating, almost melting the wires, toasted motor controller...
I'm planning to upgrade it but if you want to check it out here are some videos that I have on youtube:
https://www.youtube.com/watch?v=97JHF4jC-10&t=210s
https://www.youtube.com/watch?v=jFOmyNR1rWc&t=35s
https://www.youtube.com/watch?v=QXtdjzxoCJQ&t=66s

Here is a pic of the carnage of the wires:

 

[jlake]

Great videos, thanks.

Did you get to the bottom of why it melted the wiring and controller ? motor pulling to much current for controller/wiring ?

As you have already converted an alternator, what current / voltage did you put into the field coil rotor and how did you control it.

 

[jlake]

We got the alternator stripped this afternoon and it was a 4 wire star connected type, cut the neutral off and run it up on a RC battery and controller, and its working so have a potential motor for our little project.

Before we go off and start buying controls and batteries we want to calculate the likely power draw of the motor.

May need help from someone more brainy than I am but,

Am I right in thinking, its a 115A alternator which rectifies the ac to DC @ 12v 115A

We put my insulation tester across each phase winding pairs and got 0.1 ohm, (close as I could read the needle on my old tester) and from my college days its V over IR so 12v/0,1ohm = 120A close enough for 115A alternator.

Its 3 phase so divide amps by sq root of 3(1.73) 115A/1.73 = 66.47 A x this by what ever voltage i'm using and that's my watts.

Can someone tell me if I have my maths right here, got a feeling I may be missing something.

 

[enrengineering]

I connected the field winding to a 12v car battery, I have a monitoring display that shows a current draw of almost 6 amps.
Right now I'm testing the field winding with a PWM, more voltage to the field winding means more torque but less speed, and lower voltage means less torque but more speed. With your setup I think you need more torque than speed to spin the wheels of the drift trike.
Yes, when starting from a stop the "cheap" controller was screwed, and I was applying full throttle and causing the controller to send all the power to the motor. I used "bullet" style terminals to connect the motor to the controller, the plastic of the terminals is completely deformed due to the heat.
I recommend you to avoid any "cheap" controller (they work at short term) and invest onto something reliable like a Kelly controller or other brand.
You can also a VESC, it's like a drone ESC, but it's programmable and has almost 5 times the peak current of my cheap controller (50A). The VESC tend to get hot, so keep it cool. Here's an example of how cooling improves the performance: at minute 16:45 https://www.youtube.com/watch?v=nzdVQPxQ_0k&t=305s
Good luck with your build and keep us updated!
Cheers!

 

[amberwolf]

Am I right in thinking, its a 115A alternator which rectifies the ac to DC @ 12v 115A

it's really more like 14V or more, as high as 15v when a car is revving up, vs idling where it would be closer to 14v (above or below by a bit, depending on the load placed on it). (The lead-acid battery in the car is typically 13.6V-ish when full, so charging it requires a bit higher voltage to ensure current flow into it.)

We put my insulation tester across each phase winding pairs and got 0.1 ohm, (close as I could read the needle on my old tester) and from my college days its V over IR so 12v/0,1ohm = 120A close enough for 115A alternator.

it's pretty hard to test resistance of motor coils--they are just wire, usually thick, and/or multiple parallel strands, whcih is very low resistance, so most of the time the resistance is lower than your meter leads. Typical range is in the milliohms for higher power motors (or generators).

I just got an LCR meter capable of this low a measurement, and have an old OEM alternator out of a 1985 Ford LTD around here somewhere, so when I run across it, if i have time to open it up and measure the windings I'll post that up here for reference for you.


Regarding wattage, if it's 12v 115A for it's rating, then V x A is 12 * 115 = 1380. Since it's really more like 14v, then realistically it's 14 * 115 = 1610. So you could just split the difference and call it a 1500w device.

That is with the original fan on it spinning at the original RPM it would have when it was on the engine belt system. You'd need to find out what that RPM is for that alternator, but from the little I recall it is something around a couple thousand RPM minimum, several thousand to get the "max power" out of it (as an alternator), and a few times that is the max RPM beyond which it may mechanically fail ("grenade", where parts go flying out thru the casing).

Without the fan cooling it, I dont' know what it's max power would be--you'd have to test that by monitoring internal temperatures, and if it begins seriously heating up (130-150F and up), that's probably the max safe uncooled power. Or sniffing for the smoke while you increase the load on it. When it's failed, that's beyond the max power level. :/

 

[ShadowNightmares]

Hello, jlake, and welcome to Endless-Sphere.
I'm a fan of the projects with alternators working as motors, and i've searching about them for some time, so if i can't help you directly, i will help to find some resource that actually can help.
And now let's go to the answers:

I connected the field winding to a 12v car battery, I have a monitoring display that shows a current draw of almost 6 amps.
Right now I'm testing the field winding with a PWM, more voltage to the field winding means more torque but less speed, and lower voltage means less torque but more speed. With your setup I think you need more torque than speed to spin the wheels of the drift trike.

I already saw videos and forum threads of people that are testing/using the PWM controller for field weakening (enrengineering, Fixitmoditbreakit, Huntsteven6, and others), and it's promising, but because your idea is to have a drift trike (that will have less traction because of the plastic pipes over the rear wheels), it probably won't help you (normally the field weakening in this specific case helps more when you're already next to max rpm and use it to "stretch" the rpm range to more top speed).

Yes, when starting from a stop the "cheap" controller was screwed, and I was applying full throttle and causing the controller to send all the power to the motor. I used "bullet" style terminals to connect the motor to the controller, the plastic of the terminals is completely deformed due to the heat.
I recommend you to avoid any "cheap" controller (they work at short term) and invest onto something reliable like a Kelly controller or other brand.

The cheap controller, when working in sensorless mode, send lots of power to the motor to try and start spinning it. Recently some people have began to install hall sensors on their alternators, and even in bench tests already shows an increase of control over the motor, so i would recommend you to see these videos and think about it (from enrengineering himself: https://www.youtube.com/watch?v=7k-nG_keh1A, and from ELECTROJUANYU: https://www.youtube.com/watch?v=OoyPjsodoTQ )

You can also a VESC, it's like a drone ESC, but it's programmable and has almost 5 times the peak current of my cheap controller (50A). The VESC tend to get hot, so keep it cool. Here's an example of how cooling improves the performance: https://www.youtube.com/watch?v=nzdVQPxQ_0k&t=970s

Yes, for a VESC, cooling is important, and there's another video that show the difference between using and not using active cooling/active airflow: https://www.youtube.com/watch?v=UwVQQ_LY5bc (from hexa kopter).

 

[enrengineering]

I've been trying for a while the alternator and sensors. At the first "lap" I did around the street it seemed that it was working great, no strange noises or "jumping", but at the second lap the disaster came in. Luckily enough that I lost power when I was at the top of the street. I think I pushed too much going uphill and ended up killing the controller (I think it went under thermal protection), then I went back to the garage and put an industrial exhaust fan to cool the alternator because it was really hot, the controller also was warm.
I noticed that the terminals on the wiring that goes from the controller to the motor were completely melted (the same cause about melting the 3D printed connection terminals that I made). I decided that I am going to re-wire the alternator with 2 wires per phase of 6mm^2 silicone insulated wire (12mm^2 per phase in total) and get rid of the cheap bullet terminals.
Here is the video: https://www.youtube.com/watch?v=K_Say_pxk-A&t=2s
Use this as a reference to avoid the mistakes that I've made.
Also I'm currently searching for a new controller to try to make more power, I'm between the BAC-0501 from goldemotor and the Nucular Controller 12F from Nucular electronics, both are programmable, and I'm currently waiting for a bigger sprocket (from z36 to z48) to put on because I thing the gearing is also wrong.
Cheers.

 

[markz]

goldemotor

I've heard the goldenmotor.com isnt that great to deal with and that you should, if possible buy from goldenmotor.ca which renamed its URL. Because when you click on any product it goes to a different style website https://goldenmotor.bike

 

[enrengineering]

I live in Europe, I was thinking to purchase it from this site: https://www.miromax.lt/en/m-6/c-39/c-44-bldc_motor_controllers/product-41-controller_bldc_50100a_-_bac-0501_#to_products
they also have their own computer program for this controller.

 

[markz]

I live in Europe, I was thinking to purchase it from this site: https://www.miromax.lt/en/m-6/c-39/c-44-bldc_motor_controllers/product-41-controller_bldc_50100a_-_bac-0501_#to_products
they also have their own computer program for this controller.

BAC-0501
Why not a ASI BAC 800 from Luna?

 

[momus3]

Unless you have the specs for that particular alternator, it will be difficult to know how much DC voltage it puts out (unless you want to power it up and test it on a bench) as the voltage regulator determines that on the original vehicle, not necessarily the alternator. Could be a separate regulator, could be built in. As amberwolf said, it will be considerably more than 12 volts for sure. Just how much "considerably" will actually be is anyone's guess.

I admire the DIY aspect of these projects, but sorta prefer the easy route of buying a motor/battery/controller and making your life a little easier. Sometimes it comes out cheaper that way, and a whole lot less hassle.