# Will This 75KW Axial Flux Motor Change Jobs?



## Morf (May 29, 2009)

Hi Inductive Axial Flux Motor Fans,
The Town of Lappeenranta, Finland has a Technical University that became focused, in part, on Axial motors about 10 years ago. From that effort came an advanced Axial Flux series of motors that were designed to be mated to rotary screw air compressors, by using the compressor`s drive shaft as the motors own internal drive shaft. 

The motor types were numbered according to their KW ratings. Type 37 and type 45, weigh 122 kg. All in the series share the same case and are air cooled but with a liquid cooling option. 

Although not in the literature for the public, they also make a 75KW using the same motor case. In my last two letters from the company, I have some specs on this motor: Phase induction motor (frequency converter use). 
370V main to main~~3700 rpm~~160 A~~IP54~~F-class insulation~~air cooled with separate fan. Further, rated torque is 200Nm~~Stall torque is approx. 300NM~~Field weakening starts at 3700 rpm, the torque decreases at a ratio of rotation speed T=200Nm*3700 rpm/speed.

They have offered to do the engineering and testing to make this 75 a stand alone motor, with it`s own shaft and bearings and they have given me a prototype cost, which I want to double check before I show it. Time of development and testing would be done in 8 to 10 months. The weight of the 75 KW now is 160kg. With no transmission needed? and a simplified rear drive, I think this is what I am looking for. Please talk to me about what I may not be seeing in this build. I hope Axco gets encouragement to put this beauty on the market. Questions go to Asko Parviainen at Axco Motors. It feels like waiting for Christmas. Best Wishes everyone.


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## samborambo (Aug 27, 2008)

Morf said:


> Hi Inductive Axial Flux Motor Fans,
> The Town of Lappeenranta, Finland has a Technical University that became focused, in part, on Axial motors about 10 years ago. From that effort came an advanced Axial Flux series of motors that were designed to be mated to rotary screw air compressors, by using the compressor`s drive shaft as the motors own internal drive shaft.
> 
> The motor types were numbered according to their KW ratings. Type 37 and type 45, weigh 122 kg. All in the series share the same case and are air cooled but with a liquid cooling option.
> ...


I hate to burst your bubble but a 300Nm 160kg induction motor is not that impressive. Have a look at the AC Motor Selection wiki page:

http://www.diyelectriccar.com/forums/showthread.php?p=61212#post61212

The motor you mention has a lower torque to weight ratio than any standard industrial radial induction motor.

Yes, you will need a gearbox or reduction drive of around 4:1. 300Nm won't give you very good acceleration at the same ratio as the driveshaft. The synchronous speed of the motor would be at around 220mph with 1:1.

Sam.


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## Morf (May 29, 2009)

Hi Samborambo,
Computeritus here. Aol disconects at will this month, and I get a chance to do my letters over again. Trying to finish this letter for the third time, I left out a couple things. One was a very simplified (and light weight) drive system on the rear wheels, with a reduction. I checked a BMW locker, and a Torsen Audi, and I think it is worth the weight reduction effort to experiment with industrial drives. They treated me well on heavy equipment in the past. Tranny, clutch, differential, d.shaft, missing, I Like the 94% efficiency for the axial in it`s working range. Two of the other axial models are happy running at well over 6000rpm. I love torque, and am no expert at how much radials have at stall. But I don`t see it as a competition, prize to the best number. My hunch!! was this would serve my needs well. Thanks for your reply. Please check on my posts. I like your direct and thoughtful responses. Best Wishes,


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## samborambo (Aug 27, 2008)

Morf said:


> Hi Samborambo,
> Computeritus here. Aol disconects at will this month, and I get a chance to do my letters over again. Trying to finish this letter for the third time, I left out a couple things. One was a very simplified (and light weight) drive system on the rear wheels, with a reduction. I checked a BMW locker, and a Torsen Audi, and I think it is worth the weight reduction effort to experiment with industrial drives. They treated me well on heavy equipment in the past. Tranny, clutch, differential, d.shaft, missing, I Like the 94% efficiency for the axial in it`s working range. Two of the other axial models are happy running at well over 6000rpm. I love torque, and am no expert at how much radials have at stall. But I don`t see it as a competition, prize to the best number. My hunch!! was this would serve my needs well. Thanks for your reply. Please check on my posts. I like your direct and thoughtful responses. Best Wishes,


Morf,

Selecting parts for an EV, or any engineering project for that matter, should not be an emotive issue. Search for the parts that meet your technical criteria, (eg: torque, speed, voltage, torque to weight ratio, compatibility, compexity, etc) and fit budget requirements. Yes, it is a competition. You shouldn't be playing favourites.

Check the ABB catalogue and I think you'll find the stall torque is slightly higher than the max torque by around 10%.

An off-the-shelf toothed belt reduction drive for this power is around 5kg. Unless you're using two motors to drive the wheels independently, you'll be using a differential instead. It is common for a differential to have around a 4:1 ratio. There are examples in the DIYEV garage of AC induction motors coupled directly to the differential or transfer case.


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## Morf (May 29, 2009)

Hi Samborambo,
It was to be unanswered love, my first view of a Modec. The single copy in US sat at a winery in California, then vanished. Is it any wonder that my ev build should remind me of her. So my dream machine turns out to be a shrunken, lightened, aluminum frame railed UPS truck. Like the Modec it should travel 100 miles on a charge, be capable of hauling 2 tonnes, and charm people to think electric mobility.

Next year the Modec will come to carefully chosen areas of US, so a spokesman said. In the meantime, they are said to keep their battery lease program which makes me twitch, and the price of the Modec is near the `get a second morgage` level, so it is said. 

Back to the Axial Flux motor. The two smaller siblings of the 75 Kw come in the identical castings as the 75. However the 75 is heavier. I am guessing that it is double rotored. The 75 is also slower. I have heard that the double rotor axials of this design are turbine like in being able to lug out from stall. From years ago, I remember a fellow talking about electric motor lug out involving something that sounded like the word `chukking`. If the axial would avoid that, and I am not sure that it would, I would be most pleased with that part of it`s performance. Is this perhaps similar in sensation to the hiccuping of an i c e when left in high gear on a long incline? 
Best Wishes,


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## AlaskaStar (Feb 25, 2010)

What about the design of Axial Flux Motor that I designed and built.

I am nearing completion, and ready for testing here very soon.

http://hunteraxialfluxmotor.blogspot.com

AlaskaStar


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## dimitri (May 16, 2008)

AlaskaStar said:


> What about the design of Axial Flux Motor that I designed and built.
> 
> I am nearing completion, and ready for testing here very soon.
> 
> ...


Dude, this is the coolest thing I've seen in a while, I wish you best of luck with your motor. I am following your blog now. Please make some YouTube videos when you get that motor to spin.


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