# '92 sidekick twin AC24LS



## tomofreno (Mar 3, 2009)

Like the volks pickup! There is a thread on the Azure 24LS motors here:
http://www.diyelectriccar.com/forums/showthread.php/azure-dynamics-ac24ls-motors-81166.html

Peak power in wye config is about 45kW, and about 35kW in delta, so 2 of them in wye would be about 120 H.P. and peak torque of about 132 ft-lb. Sounds like you are well equipped!


----------



## Farfle (Jan 16, 2011)

Thanks man, the bug truck is super fun. Haven't gotten a range test in on it yet, but it sure is a screamer. That AC50 kit in a 1300lb vehicle is some serious fun. 

Some questions for those more knowledgeable than I, what's the best method for linking two motors that don't have double ended shafts? I'm torn between an oil bathed chain, like double row #40 (no idea about this just theoretically would be quieter, 520 superbike chain could handle it easily, but anybody who has heard a ttxgp flyby knows how quiet they are ), or a 1/2 or 3/8 pitch blower belt drive (would require an additional bearing support plate).


----------



## frodus (Apr 12, 2008)

PM'd you about controllers.

Remotecontact apparently has the AC24LS working with a Curtis..... so it sounds like a good option. Just needs to be correctly tuned, which shouldn't be terribly hard.... but I'd recommend a programmer to do so. Renting one will get to be a pain in the butt.


----------



## Yabert (Feb 7, 2010)

Inspiration about linking two motors: http://rebirthauto.com/RebirthAutoTwinMotorAdapters.aspx

70 lbs-ft of torque isn't that hard to transfer.


----------



## Farfle (Jan 16, 2011)

Huh, that just looks like 8mm pitch 30mm width gates belt, that's not even close to blower belt drive stuff. Hmm, I'll definitely look at that, belt drive is very appealing due to it's quietness. I wonder if that's the 1.5" Harley belt drive.


----------



## frodus (Apr 12, 2008)

Something to check out as well:
http://www.evalbum.com/1396


----------



## Farfle (Jan 16, 2011)

Huh, v pitch toothed belts. Looking more and more positive towards belt drive. And after doing one astro drive I'm kinda addicted to the turbine noise they make. Will price out gates belts options vs the v toothed belts. Thanks for all the suggestions guys.


----------



## tylerwatts (Feb 9, 2012)

Wow Farfle you've almost hi-jacked my plans! Though I will be converting an swb Rav4, and using the AC24LS motors with their AT1200 transaxles directly onto each axle to the drive wheels. Hope to get a simplistic traction control by running 2 Curtis controllers in parallel through this set-up also, though I can't get my blasted Rav to break traction with its current drivetrain - 2.0 D4-D turbo diesel chipped with estimated 300Nm peak through it's lower gears. Only in the wet will first break traction, and that is with considerable gear reduction, but the the 225 R18 tyres are pretty sticky too!

Working from the motor specs though, these should provide a very good drive set-up.

I like your plans to link to the transfer box, gives you low/hi selection, or a 2 speed box! Only concern I have is being able to switch between the two, I've always known you need to slow down a 4wd to switch between low and high range, to say ~50km/h or ~30mph for the benefit of the transmission, though if your controllers will match the motor speed with the gear being selected (tricky, but not too much so with only 2 ratios) the the gears will engage beautifully. The problem being that the transfer box does not have synchros etc, making it stronger, but harder to change gears.

I look forward to reading your progress sir!


----------



## Farfle (Jan 16, 2011)

Looks like I'll be using a belt drive to link the two motors, I found that belt drives from Harley motorcycles come in 1-1/2" widths, and the large diameter (12"!) driven pulleys are pretty inexpensive.


----------



## Farfle (Jan 16, 2011)

Question for all of you, as far as Curtis controllers go, I have two options. There will be two motors, and two controllers:

Option 1: two 108v 300A controllers. 64.8 kw peak
Option 2: two 108v 550A controllers. 118.8 kw peak
Option 3: two 136V 650A controllers. 176.8 kw. Peak

The car weighs 2800 pounds and will probably stay under 3000 after conversion. How much do I need for 70 ish mph top speed and "perky" acceleration?


----------



## rwaudio (May 22, 2008)

Farfle said:


> Question for all of you, as far as Curtis controllers go, I have two options. There will be two motors, and two controllers:
> 
> Option 1: two 108v 300A controllers. 64.8 kw peak
> Option 2: two 108v 550A controllers. 118.8 kw peak
> ...


My 944 was definitely "perky" at 120kw and 2700lbs and could easily do 70. 
Option 2 or 3 would be the choice, but assuming you are referring to the 1238's aren't they both rated for the same voltage?


----------



## frodus (Apr 12, 2008)

1238-7xxx are 130V controllers, the 1238-6xxx are 108V controllers.


----------



## kerrymann (Feb 17, 2011)

Definitely going to follow your thread. I have always wanted to do a AWD dual motor conversion with one driving each axle. I was originally thinking of a higher power DC driving the rear and the AC up front. I also have 2 of the AC24LS sitting on my bench so needless to say I look forward to your build. 

If you do decide to keep the motors separate the Curtis motors can be linked in a dual drive mode that provides rudimentary e-diff. From what I remember reading it's aimed at saving the tires in tight turns on mining equipment where the motors are split L/R but might still work for F/R distribution. Just something to consider.

Best of luck,


----------



## Salty9 (Jul 13, 2009)

Off topic but after you get the lipstick on the VW pickup it would be a good candidate for a magazine cover. Workmanship appears immaculate.


----------



## tylerwatts (Feb 9, 2012)

2 things Farfle

Driving a 4wd drive train requires more power, you'd be surprised how much extra juice is consumed by the extra driven axle and gears. Make sure the diffs and pinion gears are all adjusted well and in good health as they'll run smoother and restrict less like this.

Secondly, the 2 motors will be mechanically linked (flex in a drive belt is minimal and wouldn't matter I don't believe), so you can run them in series (higher voltage) or parallel (higher current) from a single controller. I am not saying a Curtis is sufficient though. My thoughts are the cost of 2 Curtis and the cost of 1 Scott Drive would mean the Scott drive is probably better value given it has a higher power output potential, and if you connect your batteries for reasonable voltage the motors will carry their torque through a nice wide range for the 2 spead (Hi/Low) setup better that way. It would mean only needing high range on faster roads, guessing over 50mph. 

This is what I'd go with personally, so just adding my 2c.


----------



## rwaudio (May 22, 2008)

tylerwatts said:


> 2 things Farfle
> 
> Driving a 4wd drive train requires more power, you'd be surprised how much extra juice is consumed by the extra driven axle and gears. Make sure the diffs and pinion gears are all adjusted well and in good health as they'll run smoother and restrict less like this.
> 
> ...


These are 3 phase motors, and can not simply be put in series or parallel like DC motors. One controller per motor is the only option.


----------



## tylerwatts (Feb 9, 2012)

rwaudio

I agree with where you are coming from, but you can, as long as they are mechanically linked together so rotors don't go out of synch.

If you look in Tessract's thread about these motors at the junction box, as I understand it, as long as you connect the output from the controller in series/parallel to the matching junctions on both motors, they will share the work, apart from any internal resistance where one will see more voltagte than the other, but then just run them in parallel (for each connection from the controller) at a higher current. Trouble is having a controller that can feed the amps then, but a Scott Drive can be spec'd with whichever, high A or high V, and even with a High current spec, the Scott still runs over 300V so would overspeed these motors well, making very good use of the 2 speed transmission.

I'm not saying this is a simple solution, but for the cost, seems a stronger option to go with.


----------



## rwaudio (May 22, 2008)

tylerwatts said:


> rwaudio
> 
> I agree with where you are coming from, but you can, as long as they are mechanically linked together so rotors don't go out of synch.
> 
> ...


That's fair, just trying to save the new guy who reads this and thinks he can bolt in a pair of AC24LS's a single Curtis controller and be off to the races as simply as wiring a pair of Warp9's in parallel.

To continue the subject though, how close do the rotors need to be "aligned" for something like this to work smoothly and reliably? 

(I have an AC24LS and will have a DMOC645 soon) The 645 is overkill for a single motor, however it might power a pair nicely.


----------



## Farfle (Jan 16, 2011)

I am familiar with doing multiple motors in parallel, I'm assuming they dont have current sharing issues like agnis do. And locking the rotors in sync is definitely doable. But what is a a scott drive? Never heard of it


----------



## Tesseract (Sep 27, 2008)

tylerwatts said:


> ...
> If you look in Tessract's thread about these motors at the junction box, as I understand it, as long as you connect the output from the controller in series/parallel to the matching junctions on both motors, they will share the work....


Whoa there, speed demon. You *cannot* parallel (or series) two ACIMs and drive them from one inverter using Field Oriented Control because the rotors (ie - the fields) of the motors are not electrically identical, even if the shafts are locked together.

You can only parallel (or series) multiple ACIMs if you drive them with an inverter running an open-loop V/Hz control method, but then they will have pathetic starting torque (just barely over running torque).


----------



## tylerwatts (Feb 9, 2012)

Sorry Tess

I might be leaving details out of my assumptions. I'm assuming rotor position is marked by a pick-up on the shaft (in the rear bearing on these lovely motors) so the timing is not calculated by the load on the controller. Also, in parallel the voltage should share evenly and the current pretty close to it, and flex in belt tension leading to slight momenta mismatch of the rotor timing will cause a slight loss of torque to the faster/advanced motor and bring it back in line.

My understanding is that with the rotor timed by the pick-up sensor the controller only advances the timing and current proportionate to the throttle position (ie torque demand) and should be none the wiser about whether there is one or two sets of stators connected at the other end of the output cables.

I stand to correction by others with more knowledge though! My understanding comes from another thread about a DIY AC motor and connecting 2 motors in this very manner but with both rotors on a shared shaft. Same effect for the controller though.

Farfle

the Scottdrive is a New Zealand product, AC controller, very well priced but as yet with little proven track record on this forum though the evidence seen suggests great things in my opinion. Look in the motors section for the Scottdrive thread by Ruckus!


----------



## major (Apr 4, 2008)

tylerwatts said:


> I'm assuming rotor position is marked by a pick-up on the shaft (in the rear bearing on these lovely motors)....


You do realize this is an induction motor so rotor position is irrelevant. The sensor bearing does not have a Z marker. You only get an A and B pulse train.


----------



## Tesseract (Sep 27, 2008)

tylerwatts said:


> ...I'm assuming rotor position is marked by a pick-up on the shaft ... so the timing is not calculated by the load on the controller...


To explain it very simply (and undoubtedly in a fashion that our esteemed motor guru, major, will find fault with...) the rotor is the field in an induction motor. Field-Oriented Control, then, seeks to optimize the strength and position of the magnetic field induced into the rotor in relation to the magnetic field produced by the stator (ie - armature). The electrical parameters of the rotor (ie - inductance and resistance) vary with temperature, rotor position relative to the stator poles, manufacturing variations, etc., and so it is not possible for a single inverter to find an optimal current vector solution for two rotors at the same time.

Position feedback in FOC of an induction motor is more to tell the inverter whether what it is doing is working or not...


----------



## mizlplix (May 1, 2011)

That is why this has always puzzled me: Quote from a Curtis Data sheet for the 1238 controller.


• Dual-Drive functionality is standard, allowing correct control of vehicles such as 3-wheel counterbalance trucks or other applications featuring twin traction motors. This function ensures smooth and safe operation, minimal tire wear and correct load sharing between the traction motors at all times.



I understand it is for a "differential effect" on the two motors, but why would it not work for two inlines too?

Miz


----------



## major (Apr 4, 2008)

mizlplix said:


> That is why this has always puzzled me: Quote from a Curtis Data sheet for the 1238 controller.
> 
> 
> • Dual-Drive functionality is standard, allowing correct control of vehicles such as 3-wheel counterbalance trucks or other applications featuring twin traction motors. This function ensures smooth and safe operation, minimal tire wear and correct load sharing between the traction motors at all times.
> ...


Miz,

It uses two controllers, one for each motor. Perhaps the two drives share a common command input or otherwise communicate via the VCL. 

major


----------



## frodus (Apr 12, 2008)

The dual drive on the Curtis allows two controllers to use a single throttle input, and requires VCL programming to do so.

One controller; One motor. Two controllers; Two motors.


----------



## tylerwatts (Feb 9, 2012)

My question then Tess and Major, doesn't the controller see the sum/cumulation of the 2 motors and calculate the optimum performance from this? I realize this means if the motors are not optimally locked together you'll owe efficiency but otherwise why is the controller any the wiser please?


----------



## major (Apr 4, 2008)

tylerwatts said:


> My question then Tess and Major, doesn't the controller see the sum/cumulation of the 2 motors and calculate the optimum performance from this? I realize this means if the motors are not optimally locked together you'll owe efficiency but otherwise why is the controller any the wiser please?


I don't know why you press this  But if you're intent, go ahead and try it. Here is what I posted just the other day. 


major said:


> You should plan to use a separate controller for each motor if you intend to use induction motors for vehicle propulsion. Even if 2 motors are hard coupled (on the same shaft) I see no advantage to using a single controller and there are possible problems. I have never seen it done. Quite the opposite. Some bus drives actually used dual windings in the motor and 2 inverters.
> 
> I mentioned in the other thread that the induction rotor position is irrelevant. But the control is quite sensitive to velocity feedback. Hard coupled motors would seem to solve this. But the control is also sensitive to rotor parameters which vary with production tolerance and then vary in application with temperature.
> 
> I'm not saying it absolutely can't be done. Just that it will likely be much more trouble than it is worth and ultimately more costly with no apparent performance advantage.





tylerwatts said:


> doesn't the controller see the sum/cumulation of the 2 motors and calculate the optimum performance from this?


So it will be non optimum for each motor.


----------



## Tesseract (Sep 27, 2008)

tylerwatts said:


> My question then Tess and Major, doesn't the controller see the sum/cumulation of the 2 motors and calculate the optimum performance from this?


Yes, the reflected impedance of both rotors will be summed together, but how will the inverter know which rotor contributed "x" inductance and "y" resistance? It won't, so the current vectors will be all f'ed up. That's just the way it is with induction motors; no getting around it. Period.



tylerwatts said:


> I realize this means if the motors are not optimally locked together you'll owe efficiency but otherwise why is the controller any the wiser please?


It is *torque* you will lose, not efficiency (well, not so much, anyway). Just forget driving two AC induction motors with one inverter in anything besides scalar (V/Hz) mode.


----------



## tylerwatts (Feb 9, 2012)

Tess, Major

Not trying o push it, my apologies gents. Agreed then that the motors cannot be ideally matched and locked together to maintain equivalent optimum torque output, and therefore the losses outweighs the benefits.

Farfle
My apologies for the thread interruption sir! I look forward to an update on the belt drive setup! Have you decided on how to connect to the transmission or transfer case?


----------



## hal2000 (Nov 15, 2012)

Could you elaborate a little on your decision making process with regards to component choices for this and the Porsche conversions. I have a 2002 honda insight, and would like to start squirreling away components for a pure EV conversion in the next two years. 
1. first AC, vs, DC. 

2. Next why two motors? Was cost the only factor, at $300/motor vs an ac 50. The costs go up once you add in the linkage system you mention as a possible kit, $2,000. would this still have advantages over a single larger motor controller combo in price or performance?

3. You mentioned the calib cells as your preferred battery for this build. How would this compare in price per watt/hr, to another leaf pack like you are using in the Porsche build for your boss.

Hoping that some of your reasoning for your choices might apply to my future conversion plans! thanks.


----------

