This guy is awesome. This is something I have thought about doing for a long time, but never sat down and did it. He did. In college I wanted to make one into a hub-centric bicycle drive wheel.
In the video he turns a Ford truck alternator into a go-cart motor powerful enough to go about 35kph. Probably could go faster with a bigger controller/battery.
So, what would you make with an essentially free 2-5hp electric motor?
Btw, thanks to autocorrect for the apostrophe catastrophe in the title.
Ha! I just watched this today as well and I immediately thought "I have lots of alternators and an old pedal "car" around." Then I started thinking about java's e-bike and started thinking what it would take to mount one to my bike. This lead me down the "build your own battery" rabbit hole. Was just about to doing some measuring...
I saw this video and initially thought "cool, mostly free electric motors!" then realized after all the other components required it would still be cheaper to use a HF 6.5hp motor and go even faster. Cool idea though if you have the other components laying around.
Robbie said:This guy is awesome. This is something I have thought about doing for a long time, but never sat down and did it. He did. In college I wanted to make one into a hub-centric bicycle drive wheel.
In the video he turns a Ford truck alternator into a go-cart motor powerful enough to go about 35kph. Probably could go faster with a bigger controller/battery.
So, what would you make with an essentially free 2-5hp electric motor?
challenge-priced electrically driven intake-charge compressor
barefootskater said:I saw this video and initially thought "cool, mostly free electric motors!" then realized after all the other components required it would still be cheaper to use a HF 6.5hp motor and go even faster. Cool idea though if you have the other components laying around.
Well the guy is using a fancy motor controller and pedal, but you don't need that all that. You can make on/off very cheaply or make some stepped voltage inputs (like 0-25-50-75-100%).
Autocorrect "correction" corrected. Cool video.
In reply to Robbie :
That's more like it! Sometimes my lack of knowledge/general fear of anything involving electricity is slightly embarrassing. I saw two different electric lawn mowers on CL today for less than $30 each. Makes me wonder what could be done with those. Honestly the whole electric motor thing is pretty cool just because it doesn't matter if the motor is sideways, vertical or any other orientation. Many possibilities.
Ok, this must have been a sponsored video because I watched too. This is after discussing building a power wheels racer (totally awesome, look it up) a couple weeks ago at my local maker space. Time to find a couple junk 20 or 26 in bike frames to use for rims and such.
Interesting...But a quick search yielded these comments about the reasons they aren't used as such more frequently:
Sounds like a great idea, and yet hardly anyone repurposes alternators as motors, so the question to ask first is why? The main reason is because the typical alternator is a "claw pole, wound-field synchronous" design that is exceptionally cheap to manufacturer, but only 55-65% efficient.
Another reason is you will need to do major surgery on it to use it as a motor, removing the field regulator and rectifier assembly, then bringing the leads for the field and stator out to terminal studs somehow. If you want decent torque down to 0 rpm you will also need to install either Hall effect sensors at the right locations or an absolute encoder on the shaft (and since there is just one shaft that makes mating the alternator/motor to a drivetrain more difficult).
Finally, you will need to supply the field with either a constant current, which will make the alternator/motor act like a PM type BLDC motor, or, better, with a current that is proportional to desired torque, which will let you extend the so-called "constant power speed range" greatly (via "field weakening").
As for "regenerative braking", once the diode assembly is removed from the alternator it is up to the inverter to control that. And as for the alternator being rated for 117A, that is almost certainly for a specific duty cycle and time frame, and not a continuous rating. It will likely be able to take much more current than that for brief periods (ie - seconds) but the continuous rating is likely to be much lower, particularly because of the inefficient claw pole design.
In short, the typical automotive alternator just isn't worth the time/effort it would take to use as a motor, especially given the low power levels involved.
car alternators are built cheaply and are rather inefficient, so they are not the best choice for any serious power, as a generator or motor. You can get a 2 HP 3 phase AC motor for less than $100 and it will be much easier to use and more efficient. If the alternator used as a motor on YouTube draws 9 amps at 48 volts, that is about 450 watts just for no load, whereas a similar size AC motor would draw only 100-200 watts.
From this thread: http://www.diyelectriccar.com/forums/showthread.php/car-alternator-e-bike-motor-89145.html
So it seems kind of like building a gas turbine out of a turbocharger...It's awesome in the fact that it can be done at all in the first place, but it's not particularly good once it is.
In reply to Driven5 :
yeah, that's why I limited myself to challenge... it's one of the few environments a "free" alternator is better than a $100 ac motor, or $200 4hp hobby bldc
Ah, interesting. Well I have a couple 3 phase motors laying about if someone wants to try this. I will dig them out to see what I got.
I looked at my motors. I have two 1 hp motors, one with a gear reduction and one 2 hp motor. The 2 hp motor might turn into a cart motor.
Interesting. I like the idea of the alternator as a motor, because they are already setup to belt drive and hang off a motor.
So for example you could run an electric water pump, ps pump, etc, or even on lower output engines it would help the engine a little bit too. (Double benefit because the engine gains the 1-2 hp it was losing to alternator drive, and then gains another 1-2 from the alternator driving it!)
This also goes well with sleepyhead's idea, you could run a small boost power adder from the alternator belt.
Also would be an excellent choice for reverse in a bike engined car, run a pulley on the diff input or something.
In reply to Robbie :
Driven5 said:In reply to Robbie :
whelp. Off to search for wrecked cars with eAssist in the junkyards...
An electro-compound-charged Saab ute would be awesome
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