anyone done dual motors on fixed axle

[dcastillo]

So this is my final plan, curious if anyone has done it before?

I have a fixed axle and want to use two 1000W motors in parallel connected to same controller, each driving a separate wheel/sprocket.

In my head this would give the benefit of a live axle offroad, but give the slippage required for onroad (to some extent)

do you see any issues with this setup, in my mind it seem slike it would be pretty sweet...

thanx for any insight
Danny

 

[shawnstock]

Interesting idea and I may not know what I am talking about...

BUT... any resistance variance between motors would give a different output causing them to turn at different speeds...

Even two identical 1000w motors will give variance in their outputs...

Again this is just what jumps through my mine and I could be wrong...

 

[dcastillo]

you are correct...
ie, on a left hand turn the inside/left tire will see more resistance and thus draw more current...
this means two things,
- the inside tire will be receiving more current and thus more torque (which may make turning more difficult)
- but this also means that the outside turn is free to turn faster then its being driven (by the controller) which would actually make it not draw any current and in-turn the system would look like a single drive setup, which is easy to turn on pavement

(Im leaning towards the second scenario as most likely)

the huge benefit, when offroading and one tire is seeing more resistance, the motor for that tire will automatically draw more current giving it more power...

-Danny

 

[itsid]

I wouldn't be too sure that this works.

All you said is indeed logical and a possibility,
but if you assume anything with motors like this,
it's pretty likely that Murphy will kick your behind.

I'd say in worst case it'll be option three:
both motors will push the kart on a straight line right into the parked car on the other side of the street.

Please, if you want to try this, set the controller to provide not more than let's say 250W per motor at first and slowly work yourself up.
Be careful.

'sid

 

[dcastillo]

That is the absolute best Murphys law proposal I have ever heard
I will definitely take it in to consideration...

 

[heatmizr]

I think the cons stated above are most likely overstated. Put it this way: having both wheels independently driven is FAR better than just one wheel drive, and likely better than a live/solid axle driving both wheels the same.
Even if it is No better than a solid axle 2wd, it can't be too much worse.
Please try it and let us know! But yes, use caution at first, as stated above, to stay on top of any weird handling effects.

 

[dcastillo]

I plan to try it... as soon as funding and time permit...

talking with a coworker.... a possible negative affect is, when turning the outside tire will lose all power (since its spinning faster) meaning (theoretically) i wont be able to accelerate through the turn since the power of my cart will be cut in half???? I think....

 

[itsid]

There's load changes on the rear end when turning, so the outer wheel is the one that has more traction than the inner wheel.
so it might be just the inner wheel spinning freely loosing traction completely on a tight turn at a high enough speed.

So both cases (inner or outer wheel) are potentially in danger of not drawing "enough" power from the controller.
That means, that the other wheel get's almost all the power the controller provides

There should be a sweet spot somewhere.
So if the kart is still intended for your kids to ride, make sure to test thoroughly, not only if it's possible at all to take a turn;
providing double the amount of power all of a sudden especially in a tight turn can be quite thrilling

just saying

I now I repeat myself, but please be careful... good luck!

'sid

 

[heatmizr]

I'm thinking that unless this is a racing kart, the speeds and loads will be low enough to not contribute much to any negatives. With all 4 tires gripping the ground with good traction, I don't see any/much slipping. Not sure how it will pan out if driving in slippery mud, but then any slippage there is par for the course anyway.
My gut feelings anyway.....
Dying to hear how it really works!

 

[exenos]

Personally I think it will function just like a solid axle as far as steering goes, might even be a little better. Think about the electric cars with hub motors, this is exactly like that.

 

[ML-TOYS]

The electric cars probably have a nice computerized system that controls the output to each wheel controlling traction and turning.

Just get a controller from a mobility scooter that has a joystick, it controls eacr wheel for turning, just like independent rear drive or a tank drive.

 

[dcastillo]

Lots of good thoughts thanx guys....

I will be sure to update this thread when I do, just dont hold your breath

(BTW, yes the cart is for my kids, but it will be awhile before they drive it without an adult, my daughter already drove into a concrete reinforced steel post luckily the cart only does 12mph.... though I blame my wife who was riding passenger )

-Danny

 

[heatmizr]

Lady drivers