# Voltage for 100-kW axial flux motor?



## Magnax-Daan (Feb 28, 2018)

Hi Everybody, 

For the development of a new motor which delivers 100-kW peak for a weight of 8 kg (185mm diameter axial flux motor), we are considering different choices for voltage / rpm. 

As you know, voltage relates to rpm and this motor will deliver 100-kW peak (50-kW nominal) at 12.000 rpm. For the voltage we have choices (no of turns in the windings). What is the battery voltage you would expect at 6000 rpm and at 12000 rpm? 
I presume their is a difference for the DIY or professional market. 

Thanks in advance!
Daan


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## Hollie Maea (Dec 9, 2009)

Magnax-Daan said:


> Hi Everybody,
> 
> For the development of a new motor which delivers 100-kW peak for a weight of 8 kg (185mm diameter axial flux motor), we are considering different choices for voltage / rpm.
> 
> ...


Hi Daan,

For AC motors of this size, a 360VDC nominal (400VDC peak) system is pretty standard. This would match well with the PM100DX inverter from Rinehart Motion Systems, which is the inverter of choice for many people.


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## Magnax-Daan (Feb 28, 2018)

Hollie Maea said:


> Hi Daan,
> 
> For AC motors of this size, a 360VDC nominal (400VDC peak) system is pretty standard. This would match well with the PM100DX inverter from Rinehart Motion Systems, which is the inverter of choice for many people.


Thanks for the concrete answer!
I see that there is also a version (PM100DZ) which can go up to 800V.


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## Hollie Maea (Dec 9, 2009)

Magnax-Daan said:


> Thanks for the concrete answer!
> I see that there is also a version (PM100DZ) which can go up to 800V.


Correct, and for your AF275 you should definitely wind to 800V, as there is not a DX (400V) version of the PM250, which is one of the only publicly available inverters that will be able to match the performance of this motor.


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## kennybobby (Aug 10, 2012)

i'm a big fan of the axial flux motor concept, but i would think that voltage and winding will be the last design parameters and not the first.

For example, what is the estimated torque and over what rpm range is that expected? Also how much current will be required to reach this torque? What is the expected peak torque and current and duty cycle?

From these we could select a target vehicle weight and tire size, then calculate the necessary gear reduction to meet the speed and acceleration goals.

Then we could calculate the power and energy required for the duty cycle and desired range, and the capacity and voltage needed in the battery pack.

Now with the pack voltage, the winding parameters could be selected.

just my 2¢, press on regardless and endeavor to persevere...


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## Magnax-Daan (Feb 28, 2018)

kennybobby said:


> i'm a big fan of the axial flux motor concept, but i would think that voltage and winding will be the last design parameters and not the first.
> 
> For example, what is the estimated torque and over what rpm range is that expected? Also how much current will be required to reach this torque? What is the expected peak torque and current and duty cycle?
> 
> ...


True, but it makes no sense to develop motors if the ecosystem of batteries and inverters doesn't match.


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## Chargedpolymath (Jul 10, 2018)

I think a decent and cheaper than rinehart controller that tops out about 100kw peak around 400v should be enough.12000 rpm engine and imagining using 4 of these 7kg 100kw motors on 4 wheels then u will have torque vectoring but what really interests me is with 4 motors u will need 4 controllers but those 4 controllers will be able to control 4 wheels simultaneously and somehow equally right? Have anyone converted awd torque vectoring on one of these motors?


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## Hollie Maea (Dec 9, 2009)

Chargedpolymath said:


> I think a decent and cheaper than rinehart controller that tops out about 100kw peak around 400v should be enough.12000 rpm engine and imagining using 4 of these 7kg 100kw motors on 4 wheels then u will have torque vectoring but what really interests me is with 4 motors u will need 4 controllers but those 4 controllers will be able to control 4 wheels simultaneously and somehow equally right? Have anyone converted awd torque vectoring on one of these motors?


You have to have an intelligent VCU that will determine based on your torque vectoring algorithm how much torque to demand from each controller. The company I work for, EVDrive, implemented this for a UTV.


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## Chargedpolymath (Jul 10, 2018)

So the controller of your company will control 4 of these motors without problems? What about the cost both the motors and the controllers?


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## sjd.aliyan (Jan 17, 2018)

Magnax-Daan said:


> Hi Everybody,
> 
> For the development of a new motor which delivers 100-kW peak for a weight of 8 kg (185mm diameter axial flux motor), we are considering different choices for voltage / rpm.
> 
> ...


You are asking your question upside down!
First you have to have your designed motor's kv then calculate by what voltage you will get 12k rpm.
If its for a ev i suggest you to use voltages higher than 500v if you have no problem with development of your own bms and charger.800v is a trend


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## Hollie Maea (Dec 9, 2009)

sjd.aliyan said:


> You are asking your question upside down!
> First you have to have your designed motor's kv then calculate by what voltage you will get 12k rpm.
> If its for a ev i suggest you to use voltages higher than 500v if you have no problem with development of your own bms and charger.800v is a trend


He can set the kv to whatever by modifying the winding. So he asked what the market prefers.


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