MAC Motor Stator+Rotor ReDesign. Guru Help needed.

[Kiwi]

Hi.

I am designing a high powered geared hub motor for production.
The mechanical side of things we have sorted. But I have little experience in the design of the laminations, magnets and deciding the pole count, tooth depth ect, general electromagnetics.
The motor is based of the MAC/ BMC/ Ezee.

From my experience with the MAC, heat is an issue for us. Something is not right that the cables and motor get hot in our application.
Our ultimate goal is low speed torque.
We are aiming to 50v and 95 phase max, battery current around 30 amps.

Basically Im open to the voice of experience to help me design the stator and rotor.
We have a good heat flow from the base of the laminates and out the motor.

Like I said, the goal is torque at low speeds. The motor still has to spin up, but it needs to grind too. 5:1 reduction is maintained. I can get desired RPM once discussion starts.
If people throw some ideas around I will cad the core and post it back up for more feedback.

If you have links to good design guides let me know.
I know we can get much better heat handling than the mac for our application, and I cant help but feel its the high pole count causing some sort of issue, need to learn.

Help.
Kiwi.

 

[izeman]

if you say your motor will be BASED on the MAC: what parts are you gonna use? which are you planning to build?
are you just trying to keep dimensions and feed it with 40/90a? i do this, but i have the MAC modded "crossbreak" style and use it as a middrive. that way the motor can be kept "cool" with up to 2kW.
btw: do you have an old 0,35lam MAC to sell maybe? i'm looking for one ...

 

[liveforphysics]

It's extremely specialized work to make a system with BEMF that won't cause harmonics that make it an inefficient hassle to drive it.

You need Miles or Farfle or Biff to design review your lams.

 

[Kiwi]

Thanks Luke.
There is a Job going in New Zealand for and electrical engineer, CTO with our motorcycle company if you know someone. We had one guy from Zero interviewed, but wasn't really into startups.

I have started my education by attempting to model the MAC into Emetor. txt and Pdf, if someone wants to check it over and see if I have it correct.
We work with Mac motors, and they gave me the materials. Im not sure about my slot fill.

We are looking to do a 2kw rear with a goal of 100nm at the wheel. perhaps with 6:1 reduction in the hub which will allow a slightly larger diameter rotor.
The front motor cant put down more than 1kw so we would do a 1kw up front.
Currently the mac is 1700rpm so 340rpm at the wheel. We are using some phase weakening to get an extra bit of speed beyond that.
SO if we went 6:1 we would be looking for roughly 2000rpm.
We have potentially very good heat dissipation compared to regular hubs.
We are not trying to revoutionise the motor here, only design to high torque, low weight, low heat.
50v input.

Twice the torque of the Mac would be a outcome.


View attachment mac5.txt
View attachment mac5.pdf

 

[neptronix]

Twice the torque of the Mac would be a outcome.]

If it's under $600, i'll buy the first one. No joke.As long as you use the thinnest lams possible.
I like the mac... but the efficiency could use some help due to the downside of being geared.

 

[Samd]

I've been talking to Damus and Echo at Mac about some changes to their motor and they have something there you might be into. I'll pm you Kiwi when I get a chance.

You wouldn't go for a 29mm DD motor instead on a winding that is suited to 50V? I can get Mxus to do a few custom winds if needed.

 

[Kiwi]

Yes. Mac are working on more powerful motors.

 

[neptronix]

I know what mac are up to. I rode it. Its not working out for them. This work will help.

I heard that.

Been waiting for them to get a bigger motor going since 2012.. best of luck with your engineering quest, sir.

 

[spinningmagnets]

I'm certainly no motor guru, but...Does it need to fit in-between 135mm drop outs? Does it need a 7-speed freewheel (or would a single-speed freewheel be adequate?)

Doctor Bass said he gets unacceptable traction slippage at 2000W peaks on the front tire, so...since the MAC can already do that, I don't think you'd have to restrict yourself to something that uses the same motor, but still fits on a 100mm fork drop-out. So I assume this would only be a rear geared motor? If it's only for a rear hubmotor, does it absolutely need a disc brake option?