# Creating motor(s) from Honda IMA



## Sonikaccord (Dec 17, 2012)

I have been thinking recently about how I could implement the Honda IMA drive system into a single motor.



It uses a segmented stator which makes for an easy rewind using flat wound magnet wire

May be possible to pump coolant through the stator provided you could keep it sealed and prevent it from leaking onto the rotor.

I was thinking mainly about how to optimize packing and power density. With water cooling, I don't see why you couldn't pump 300+ amps per module. According the ornl chart on the 05 accord hybrid, that would equate to about 150-200 ft-lbs. A stack of 5 of them would be close to 800 ft-lbs that weighs in at close to 200 lbs and that is about 13 in long. Not bad. Let's try to improve on that.

Physically. we could chop off about 50 lbs from the extra aluminum from the case and shrink it to 9-10 inches long. If we remove all of the individual stator bobbins and machine down the lip on the rotor and fit them together, we could have a 'continuous' motor. Here is where I have a couple of questions.

What is the best way to make a continuous stator segment and the drawbacks of doing so?

On the rotor side, would the individual magnets in the rotor interfere with the magnetic field of the rotor as a whole? Connected together of course.

Is there any benefit to making a continuous motor, vs just connecting the individual segments, besides the physical benefits?

EDIT: Also the rotor laminations are taller than the stator laminations, so I don't think it would be feasible to make a continuous motor. There would have to be at least a 1-1.5mm space in between the modules. So would stacking them together with that bit of space between modules make a big difference?


----------



## dougingraham (Jul 26, 2011)

Are these IMA assemblies really inexpensive and readily available? The rule of thumb in motors is that the best efficiency occurs in a so called square motor. This is where the diameter is equal to the length. You can increase torque by making the motor larger in diameter, making it longer, or increasing the number of turns of wire. All have have downsides. If you increase the diameter the RPM must generally be limited due to physical limitation on the materials used staying in place. If anything shifts then the rotating bits are out of balance and it shakes itself apart. If you make the motor longer then you have problems with balance and bending of the rotating parts. You also end up with increased winding resistance due to the length of the wire. Increasing the number of turns of wire has the disadvantage of increasing the length and decreasing the diameter of the wire (increased resistance) but you sometimes get better copper fill of the slots.

It looks to me like these are purpose designed as starter motors that can also be used as generators to recover some energy during braking and provide some boost during acceleration. They are really too small to be used as drive motors for very long which explains your reasoning for ganging them together. My feeling is that there are too many issues to overcome if you gang a bunch of these together. Controller (inverter) complexity is one of the biggest. You either have to get one big device and wire all the pieces together so it looks like one motor or you get a controller per motor piece and make them work together. The motor is the easy part, the controller is a larger problem.

Best Wishes!


----------



## Sonikaccord (Dec 17, 2012)

Very inexpensive. With some shopping around and some persuasion, I could probably get them for about $200 a piece.

Diameter will stay constant. The stock redline of the Accord ICE is 6500 rpm, The IMA will probably be stable up to 7000 rpm. I would love to do a destructive test of one just to see how high it can physically go and other physical and electrical limits of the system. Only the other two methods are viable. If I keep it square, it would be appx. 13 inches long. A 6 rotor system.

I was also thinking about the balance as well as the torques applied onto the mating shaft and the material that the shaft would have to be. Carbon fiber would be cool but expensive. So aluminum may be the best choice for weight and strength.

Windings: This one is tricky. I could do the continuous stator and have one long coil per pole or I could do them individually which would be akin to having multiple motors with phases in parallel. I would have to digest the pro and cons of both.

They are designed for intermittent duty, which is why I mentioned the water cooling to increase the reliability of the system.

I agree. The motor is relatively easy. If I decide to follow through, I do have a few ideas I'd like to throw around for the controller. I could treat them as one big motor, which would be the easiest. I use that term lightly. Or, I could do them individually and that opens up a whole other can of possibilities/worms.

Thanks!


----------



## marcexec (Feb 11, 2009)

Did you make any progress on this? Was considering 2 in a small FWD direct drive application.


----------



## samwichse (Jan 28, 2012)

Much more work was done on this idea at insightcentral.net 

Still no final product though:
http://www.insightcentral.net/forums/showthread.php?t=17822

The Insight motor itself can take about 20kw max (stock wired) before the permanent magnets cry uncle. The Accord unit is a bit stouter. There are no bearings/end plates. Just a stator hanging off the end of the engine crank and positioned under the flywheel and an aluminum spacer between the engine and transmission with the coils in it.


----------



## marcexec (Feb 11, 2009)

Thanks, interesting read.


----------



## Sonikaccord (Dec 17, 2012)

Bump.

So I actually bought one of the Accord Hybrid IMA's a few weeks ago just to get a feel for the physical dimensions and assembly of the unit. 

I have details and pics that I will upload later. The stator and rotor are really easy to stack on the Accord IMA. The hardest part will be the bearings and shaft fabrication. By hardest, I mean the most time consuming. Other than that, it looks like a potentially cheap, powerful synchronous motor.

Also, I think it bolts to the TL-S manual transmission. It would be better to design an endplate to make a universally adaptable motor.

Edit: Wow! This thread has almost 2k views. I didn't know there was that much interest. I may move this a bit faster then


----------



## Tomdb (Jan 28, 2013)

what version do you have? Im working with gen 2 hardware.
see my thread and progress.
http://www.diyelectriccar.com/forums/showthread.php/honda-ima-163650.html


----------



## Sonikaccord (Dec 17, 2012)

I just took a quick glance at your thread. It looks like you have the Civic IMA.

I have the 1st Accord hybrid IMA. I'll look at it some more when I get home.


----------



## bigmotherwhale (Apr 15, 2011)

Have you considered oil cooling the stator? 
making sure none collected between the stator and magnets and made more heat than it took away would be my biggest concern but i think it could be done.


----------



## Sonikaccord (Dec 17, 2012)

bigmotherwhale said:


> Have you considered oil cooling the stator?
> making sure none collected between the stator and magnets and made more heat than it took away would be my biggest concern but i think it could be done.


I have thought about a directly cooling the winding with either a water/glycol mix or transformer oil/ATF. That's further down the road as it won't be an easy application.


----------



## Sonikaccord (Dec 17, 2012)

This motor is a little rusty, but it's fine as it is only for measurements and mock-ups.


----------



## Sonikaccord (Dec 17, 2012)

Everyone likes pictures!!


----------



## Matej (Dec 4, 2015)

Can you please tell me if the IMA motor (or should I see the inner rotor) spins freely when it is separated from the gasoline motor and transmission? What keeps the rotor in place once it is unbolted from the gasoline engine?

I am curious because I thought one of these could be easily used as a transmission adapter between a main electric motor and transmission, since it already has provisions for a flywheel to bolt to it.
Not to mention it could be potentially purposed as a standalone regenerative braking system.


----------



## Sonikaccord (Dec 17, 2012)

No, it doesn't. The crankshaft and the transmission's main shaft act as the bearings for the IMA motor. Once the IMA is removed, the rotor will just be attracted to the stator and the strength of that attraction holds the rotor in place. It has no support, and is not centered in this state. You have to fabricate endplates and bearings before it becomes useful for anything besides a paperweight (although it does a very nice job of being a paperweight  ).


----------



## Spaceweasel (Mar 30, 2013)

Any progress on this front? I stumbled across the IMAs on eBay and came to the same thought about joining them together.


----------

