# High Power Density Motors



## samborambo (Aug 27, 2008)

Flying_Jake said:


> Hi There,
> 
> I’m designing a project which requires a very high power density motor.
> 
> ...


Jake, you haven't mentioned what you want the motor for. Its hard to suggest a particular type of motor without knowing what its for.

Also, do some study on motor theory. A high power density is easily achievable if you can tolerate gearing down a very high speed motor. I feel like I say this at least once a week on this forum: motor size (weight) is more closely related to torque, not power.

Are you sure you need 60kW continuous? 15kW continuous is the most a small vehicle (car) needs for 100km/h. Can I assume from your name that you're looking to build/convert an electric aircraft?

Sam.


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## CroDriver (Jan 8, 2009)

Hi Jake.

There's a problem with that companies you mentioned... They will sell their products ONLY to OEM's. Believe me, I've tried it...


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## Flying_Jake (Jul 21, 2009)

> There's a problem with that companies you mentioned... They will sell their products ONLY to OEM's. Believe me, I've tried it...


edit: Well I tried, thought I had it then they pulled out since I was a home hobbiest. Too expensive anyway.

Thanks samborambo for your input. I am aware that motor size and weight is related to torque, as well as the cooling used (water / air), and the technology used (BLDC , reluctance, induction, etc) etc etc. I just wanted to know if anyone knows of other companies that sell high power density motors around the 60KW mark, irrelevant of speed.



Cheers


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## CroDriver (Jan 8, 2009)

Flying_Jake said:


> Y
> I just wanted to know if anyone knows of other companies that sell high power density motors around the 60KW mark, irrelevant of speed.
> 
> 
> ...


I think that this guys want to sell to anyone 

http://www.evo-electric.com/products/electric-motors-and-generators-hybrid/

I almost purchased their 290 kW system.

No matter if available or not, I'm pretty sure that it will be very expensive. Take a close look at DC systems, maybe you find what you need for a fraction of the AC system price


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## samborambo (Aug 27, 2008)

Flying_Jake said:


> Thanks samborambo for your input. I am aware that motor size and weight is related to torque, as well as the cooling used (water / air), and the technology used (BLDC , reluctance, induction, etc) etc etc. I just wanted to know of ... motors around the 60KW mark, irrelevant of speed.
> 
> 
> 
> Cheers


I still don't think you understand. Your last statement is contradictory. Power is a function of speed. You could take a 30kW motor, overspeed it by 100%, maybe install better bearings, use a higher voltage drive and get 60kW out of it without stressing the motor.

eg: http://www.lehner-motoren.com/preise.php has an 11kW 50kRPM motor weighing 1.6kg, 95% efficient


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## Flying_Jake (Jul 21, 2009)

Thankyou CroDriver for that link, that motor may be close to what I need. 



samborambo said:


> I still don't think you understand. Your last statement is contradictory. Power is a function of speed. You could take a 30kW motor, overspeed it by 100%, maybe install better bearings, use a higher voltage drive and get 60kW out of it without stressing the motor.
> 
> eg: http://www.lehner-motoren.com/preise.php has an 11kW 50kRPM motor weighing 1.6kg, 95% efficient


Power is a function of speed and torque. For my application the motor has to be 100% reliable. If it breaks down the person may die. Ok let me think this through, please correct my theory if I am wrong. The heat power that is dissipated by the motor is a function of the current flowing through the coils (due to resistance in the coil). So I agree with you, I could double the supply voltage, and then overspeed the motor to double the back EMF, and thus reduce the current to the same level it was previously while having a doubled power output. The reason I don't want to do this is because of the following reasons. 1) The motor will be rated to a certain speed. Going over this may damage the motor, or I cannot guarantee reliability. 2) The insulation between the windings is only rated to a certain voltage, so again it will probably work, but again I cannot guarantee its reliability. 3) Bearings and rotor may break, however as you suggested I can replace the bearings with better ones with some effort.

Also finding a controller that does around 600V may be an issue?
When I say "irreverent of the speed" I mean I don’t mind if its 4000, or 10000 rpm, as long as it has a relatively high power density. I agree higher speeds will tend to have higher power densities; I just don't want to exclude some pretty good lower speed motors.

I should have stated I need the reliability of this application to be very high. Thanks for your comments, you are helping me to think more clearly about what I need.

Cheers


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## samborambo (Aug 27, 2008)

Flying_Jake said:


> Thankyou CroDriver for that link, that motor may be close to what I need.
> 
> 
> 
> ...


Jake, you still haven't mentioned what this is for. This is a place to share ideas and get advice within the DIY community. Its not just a free information service. Explain what your project is and maybe someone can help.

Sam.


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## Flying_Jake (Jul 21, 2009)

samborambo said:


> Jake, you still haven't mentioned what this is for. This is a place to share ideas and get advice within the DIY community. Its not just a free information service. Explain what your project is and maybe someone can help.
> 
> Sam.


Sport water application, but I don't want to go into details. In a couple of years maybe.

Cheers


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## samborambo (Aug 27, 2008)

Flying_Jake said:


> Sport water application, but I don't want to go into details. In a couple of years maybe.
> 
> Cheers


In a speed boat? Why the power density then? A 150kg 30kW continuous / 100kW peak 3000RPM induction motor would give excellent results in a speed boat. If geared to run at 6000RPM max and developing full torque up to 4500RPM, you'd get 150kW out of it. Modify the aluminium frame to allow water cooling instead of air cooling and you'd get at least half the power continuous. All for around US$2500. Bargain.

Sam.


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## Tesseract (Sep 27, 2008)

Flying_Jake said:


> Sport water application, but I don't want to go into details. In a couple of years maybe.
> 
> Cheers


Expanding on what samborambo said, this ain't a _one-way_ free information service. You want help with something, you need to tell us what it is you are up to (and as someone who designs power conversion electronics for a living I am just _waiting_ to rip off your idea...  )

The amount of secrecy you can afford to shroud an idea in is inversely proportional to your ignorance of what it will take to make the idea work.


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## samborambo (Aug 27, 2008)

tesseract said:


> expanding on what samborambo said, this ain't a _one-way_ free information service. You want help with something, you need to tell us what it is you are up to (and as someone who designs power conversion electronics for a living i am just _waiting_ to rip off your idea...  )
> 
> the amount of secrecy you can afford to shroud an idea in is inversely proportional to your ignorance of what it will take to make the idea work.


roflmao!


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## Flying_Jake (Jul 21, 2009)

Tesseract said:


> Expanding on what samborambo said, this ain't a _one-way_ free information service. You want help with something, you need to tell us what it is you are up to (and as someone who designs power conversion electronics for a living I am just _waiting_ to rip off your idea...  )
> 
> The amount of secrecy you can afford to shroud an idea in is inversely proportional to your ignorance of what it will take to make the idea work.


I can not tell you details without breaking a promise to people close to me, I'm sorry. The only help I wanted was in obtaining a variety of motor manufacturers, that is all. Sorry for being ignorant by posting a simple question and trying to obtain free information.


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## Bowser330 (Jun 15, 2008)

samborambo said:


> In a speed boat? Why the power density then? A 150kg 30kW continuous / 100kW peak 3000RPM induction motor would give excellent results in a speed boat. If geared to run at 6000RPM max and developing full torque up to 4500RPM, you'd get 150kW out of it. Modify the aluminium frame to allow water cooling instead of air cooling and you'd get at least half the power continuous. All for around US$2500. Bargain.
> 
> Sam.


2500$ for 100kw peak AC Induction motor? Please link me!


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## samborambo (Aug 27, 2008)

Bowser330 said:


> 2500$ for 100kw peak AC Induction motor? Please link me!


The ABB catalogue is linked on the AC Motor Selection page on the wiki.

Sam.


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## samborambo (Aug 27, 2008)

Flying_Jake said:


> I can not tell you details without breaking a promise to people close to me, I'm sorry. The only help I wanted was in obtaining a variety of motor manufacturers, that is all. Sorry for being ignorant by posting a simple question and trying to obtain free information.


I couldn't give a rats ass who you promised. You're looking to capitalise on information you get from this forum without any intent of sharing anything in return. It goes against the whole principal of free information exchange. 

I'm happy to give you advice but you'll have to pay for it from now on. 
Sam.


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## Flying_Jake (Jul 21, 2009)

samborambo said:


> I couldn't give a rats ass who you promised. You're looking to capitalise on information you get from this forum without any intent of sharing anything in return. It goes against the whole principal of free information exchange.
> 
> I'm happy to give you advice but you'll have to pay for it from now on.
> Sam.


 I am quite content without your advice samborambo, you are too hot-headed for me to work with anyway. Free information exchange is just that. Free. 

edit: I found some motors, see below. Actually I decided to go for a motor from china since the weight doesn't matter to much. Just want it small.


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## CNCRouterman (May 5, 2008)

Flying Jake,
There are a lot of very smart people that contribute on this forum, and though Samborambo may have ruffled your feathers, the point is valid. You do not have to dishonor your non-disclosure agreement to share enough information to allow for an informed recommendation. So, even if your project is a personal watercraft, or a personal one-person airlift contraption using your yet to acquire electric motor powered by yet to be revealed zero-point energy source, you can still describe the operational parameters, and perhaps working environment. This will help form the context for the search for your solution.

As an aside, the data you have already made public suggests a man-carrying aviation product, so whether that is true or not, if it is consistent with the operational parameters you require, you could phrase your request as such.


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## Flying_Jake (Jul 21, 2009)

Here's a list of motor makers I have found
edit: update list, I suggest people try the china-electricmotor,they are happy to sell to hobbiests. 

http://www.china-electricmotor.com
http://www.letourneau-inc.com
http://www.enovasystems.com
http://www.acpropulsion.com/
http://www.calmotors.com/
http://www.uqm.com/
http://www.brusa.biz/
http://www.mes-dea.ch/
http://www.evo-electric.com/


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## CNCRouterman (May 5, 2008)

Allow me to expand on things you can probably answer as yes, no, not applicable, or doesn't matter. Using "to be determined" is kinda lame, I know, because I have used that excuse myself, which inevitably means that I haven't properly thought though the project, or results in the project not going anywhere until the "to be determined" parameter is addressed. Often the TBA is actually a dependent variable based other given parameters. 

This certainly does not invalidate your search, as it will help you to focus your feasibility study by limiting certain parameters to available choices.

So, for the sake of discusion, consider the following as a starting point.

Requirements:

Power density, kw/kg or similar.

Design; as in explosion proof, drip proof, totally enclosed, open, pancake, gear reduction.

Features; reversible, constant power, constant torque, variable speed, fixed speed, service factor, temperature tolerance, air cooled, forced air cooled, liquid cooled, conduction cooled.

Characteristics; synchronous, induction, switched reluctance (which seems to have some promise), etc.

Will the motor be stationary like a airconditioning drive, or building ventilation air handler, or will it be mobile. If it is mobile, then you want to consider things like shock, vibration (external), gyration (bearing loads), etc.

Will the output shaft be direct coupled or overhung (pully or sprocket drive).

Answering some of these may invite further contributions.

I ran across one resource which may warrant further investigation on your part. SRMDrives.com They promote a switched reluctance drive which (according to their pitch) has a higher dependability due to simple design, that is to say no copper windings on the rotor, unipolar, simpler controller etc. etc.


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