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Most Efficient Motor

33801 Views 77 Replies 14 Participants Last post by  IamIan
I am curious if any one knows of any electric motor someone can buy that is more efficient?

Thanks.

CSIRO Motor ~98% Efficiency
http://www.csiro.au/solutions/psz7.html

which is compatible with:
Wavesculptor20 Controller ~99% Efficiency.
http://www.tritium.com.au/products/TRI50/index.html

( ~97% Combined Efficiency )

I understand the top end of efficiency like any top end of performance comes at a price premium ... so it is understood from the beginning to be expensive beyond being practical ... I was just curious if anyone knows of better.

I also understand that efficiency is not a set thing and does change based on a variety of factors , RPM , Voltage, Current, Load, Temperature, etc... But even looking at some of the documents for these two ... it still looks like the combination would be hard to beat for efficiency... even as a net over all operating efficiency.

And although expensive , they are commercially available to buy right now today ... I have little doubt there are some hypothetical motors and controller that could be better ... but I was more curious about if there is anything actually available that is more efficient??

If you are aware of something better ( more efficient ) ... please post ... thanks.
:D
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Can you cite any reference to induction motors only attaining half their rated performance when in negative torque? I've never come across such a statement before. I can't think of any technical reason why this would be the case.

Just did a quick comparison of peak torque between a netgain warp 9 and a 4 pole aluminium frame 25hp induction motor. 15% more peak torque in the induction motor and 25lbs less weight. These are standard industrial motors - not even optimised for EV use. Plus they're much cheaper than the DC motors I've seen.

Sam.
is that using the down under "reduced voltage" ,then increasing voltage as hz goes up . nice work . I just felt that would be the case .
 

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Discussion Starter · #42 ·
just saw the post thanks, now to figure it out!just spent 4hrs. posting on the jag/capstone turbine ,burnt!in a good way .added: 9.54 x 100 rads =954 rpm ?
yes. You got it.

___ radians / second * ~9.54 = ~ ____ RPMs

so 100 radians / second = ~954 RPMs

Of course ~ is because you are rounding off Pi.
 

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Discussion Starter · #44 · (Edited)
Well if you want to nit-pick. Of course they use different components of cost vs performance. The topologies are identical.
It isn't nit picking when from the beginning I have been referring to specific components to still be doing so... it is the very concept this thread was started on.

Ian, if you start treating the design or specification of components in a system in isolation, you'll be running in the dark. You simply cannot continue a conversation about the most ideal/efficient motor for an EV unless you look at the bigger picture:
As already stated ... we know the context will have significant influence ... we also know that each tiny piece of the context can each by themselves be an entire thread on their own ... to try and discuss the whole bigger picture all at once , ends up including too many topics and guesses to be usefully confined to one thread / topic.

Most ideal and most efficient are entirely different things... for a wide variety of reasons... this thread is not about most ideal ... which is a very different topic.

The 'bigger picture' is only relevant if the threads topic of 'most efficient motor' were exclusively for a specific predetermined EV context... which is not what I was looking for ... that would be more useful in that one specific context ... but would be just as much less useful in any other EV context.

Put in other terms ... I am looking at it from a 'component level' design of the system not the components themselves ... instead of a 'higher level' design of the system... Yes I understand the 'higher level' design method is far more common to identify the performance requirements first and then determine the components for those requirements second ... but systems can be designed in a variety of ways ... in this specific context I am looking at one metric out of many metrics of motors and controllers ... as I said this specific topic is not trying to cover all the contexts ... but specifically the one metric of efficiency ... and in the metric of efficiency not all aspects of the vehicle but the motor and controller specifically.

Granted this view / method has its restrictions and limitations ... and I understand that.
 

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It isn't nit picking when from the beginning I have been referring to specific components to still be doing so... it is the very concept this thread was started on.
So you were hoping to get an answer at the end of this thread that, for instance, the most efficient motor/controller combination is a Solution 1 with a 9" Netgain. Many posters (before I chimed in) identified the flawed logic of the value of efficiency vs battery capacity, peak efficiency vs wide band, etc. That's probably the reason why we're still debating over the type of motor, let alone make and model.

As already stated ... we know the context will have significant influence ... we also know that each tiny piece of the context can each by themselves be an entire thread on their own ... to try and discuss the whole bigger picture all at once , ends up including too many topics and guesses to be usefully confined to one thread / topic.

Most ideal and most efficient are entirely different things... for a wide variety of reasons... this thread is not about most ideal ... which is a very different topic.

The 'bigger picture' is only relevant if the threads topic of 'most efficient motor' were exclusively for a specific predetermined EV context... which is not what I was looking for ... that would be more useful in that one specific context ... but would be just as much less useful in any other EV context.

Put in other terms ... I am looking at it from a 'component level' design of the system not the components themselves ... instead of a 'higher level' design of the system... Yes I understand the 'higher level' design method is far more common to identify the performance requirements first and then determine the components for those requirements second ... but systems can be designed in a variety of ways ... in this specific context I am looking at one metric out of many metrics of motors and controllers ... as I said this specific topic is not trying to cover all the contexts ... but specifically the one metric of efficiency ... and in the metric of efficiency not all aspects of the vehicle but the motor and controller specifically.

Granted this view / method has its restrictions and limitations ... and I understand that.
I'm not sure that you do understand the restrictions of your design method. Imagine if an automotive engineer started a clean-slate design of an entire car by first designing the alternator. No consideration made of intended market, performance, budget or any other high level question. A "bottom-up" approach like this appears to me to be utter insanity. I've never seen such a method taught as good engineering practice - for good reason.

Many people have asked me why I'm using an induction motor for my current conversion. My short response has always been, "Because it's powerful, efficient and cheap". The long response is, "Since I have chosen (objectively, due to other design considerations) to use a manual gearbox without the remote gear stick, leading to a fixed reduction, an induction motor provides the widest power band while remaining very efficient at partial loading. Also, the motor cost me US$40 second hand."

Do you see the difference? My short answer has no context and mostly irrelevant even to another EV DIYer. Do you see now how counter-productive it is to try and prescribe a specific motor/controller without a design context?

Sam.
 

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Discussion Starter · #47 ·
So you were hoping to get an answer at the end of this thread that, for instance, the most efficient motor/controller combination is a Solution 1 with a 9" Netgain.
Something like that.

Although I was also hoping to see some other examples ( I didn't already know about ) of very efficient motor and controller combinations.

Peak Efficiency could be one category.
Average / Nominal Efficiency could be another.

Many posters (before I chimed in) identified the flawed logic of the value of efficiency vs battery capacity, peak efficiency vs wide band, etc.
Not flawed logic ... the limited scope / basis of the intent ... I was one of them in the very first post that acknowledged several other factors that not only influence efficiency ... and that the best efficiency is not necessarily practical or cost effective.... etc.

That's probably the reason why we're still debating over the type of motor, let alone make and model.
The debate about what types of motors and types of controllers could potentially do ... I don't see as ever getting anywhere ... it is not real components ... it is what imaginary components might be able to do ... not comparing the real specs and performance of real components you can actually buy today... feel free to continue it if you like ... but it wasn't the direction of my intent ... but if you think that method will get you to the most efficient combination ... good luck.

I'm not sure that you do understand the restrictions of your design method.
Fair enough ... but sense I don't have telepathy , I'm not sure what other words I can type that would help you with that.

Imagine if an automotive engineer started a clean-slate design of an entire car by first designing the alternator. No consideration made of intended market, performance, budget or any other high level question. A "bottom-up" approach like this appears to me to be utter insanity. I've never seen such a method taught as good engineering practice - for good reason.
I never said the top down / higher level type of design did not have good reasons for it , or any benefits, or was not common ... in fact I already posted the exact opposite ... I am well aware that method is very common and can have some benefits.

Sense I am not intending on designing imaginary components that don't exist, but instead looking specifically at specific real world components that already exist ... a closer variation of your example to my direction would be something like the bellow example:

Refined Example:
Imagine an Automotive engineer starting out the design of a vehicle by looking into what ICE designs / options were the most efficient ... the ICEs that were currently in production somewhere ... ones that were real and not just imaginary or what might be possible, but what was already being achieved ... what available ICE options would maximize his energy conversion from stored chemical energy to mechanical motion.

Many people have asked me why I'm using an induction motor for my current conversion. My short response has always been, "Because it's powerful, efficient and cheap". The long response is, "Since I have chosen (objectively, due to other design considerations) to use a manual gearbox without the remote gear stick, leading to a fixed reduction, an induction motor provides the widest power band while remaining very efficient at partial loading. Also, the motor cost me US$40 second hand."

Do you see the difference? My short answer has no context and mostly irrelevant even to another EV DIYer. Do you see now how counter-productive it is to try and prescribe a specific motor/controller without a design context?
And that very well might have been the best choice motor for your specific context... $40 is pretty sweet.

I understand the benefits of a higher level / or more top down ( usage context first ) approach to the design ... it isn't hard to grasp... Although you don't seem to beleive me... oh well ... shrug.

I do not agree however that it is the only way to design anything... or that any other method is counter-productive... or that there is nothing to be gained from any other method ... etc.
 

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Can you cite any reference to induction motors only attaining half their rated performance when in negative torque? I've never come across such a statement before. I can't think of any technical reason why this would be the case.
Found this:
http://electojects.com/motors/tesla-induction-motors-4.htm
Guess I was wrong. I was under the impression that although the thermal power rating doesn't change, they just don't put out the same level of power. That might have been a matter of application..
 

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Discussion Starter · #49 ·
So you were hoping to get an answer at the end of this thread that, for instance, the most efficient motor/controller combination is a Solution 1 with a 9" Netgain.
Yes I know you were just using them for instance ... but I figured I'd do a little looking anyway.

Although the Netgain motors are fine for other things ... winning for most efficient does not look like it is going to happen.

There are different Netgain 9" ... but all 3 of them the Impulse , Warp , and Transwarp ... all look less efficient that we have already seen from the CSIRO ... or from the Honda IMA motor ... or from the AC150.

http://www.go-ev.com/images/003_08_04_ImPulse_9_SpreadSheet.jpg
http://www.go-ev.com/images/003_09_02_WarP_9_SpreadSheet.jpg
http://www.go-ev.com/images/003_16_TransWarP_9_SpreadSheet.jpg

I have not yet found a efficiency chart , or spec sheet for the soliton 1 ... to know where it stands in comparison ... do you have any suggestions on where to find it , by all means let me know ... that would be interesting to see.
 

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http://www.go-ev.com/images/003_08_04_ImPulse_9_SpreadSheet.jpg
http://www.go-ev.com/images/003_09_02_WarP_9_SpreadSheet.jpg
http://www.go-ev.com/images/003_16_TransWarP_9_SpreadSheet.jpg

I have not yet found a efficiency chart , or spec sheet for the soliton 1 ... to know where it stands in comparison ... do you have any suggestions on where to find it , by all means let me know ... that would be interesting to see.
Hey IamIan,

Those are brushed DC motors. Would anybody think they would be efficiency winners in your contest?

And the Solitron likely does have higher peak efficiency than your favorite rival because it has a single switch in series with the load. So what? They don't advertise it because it really does not matter. Hell, a contactor controller has the highest efficiency.

Regards,

major
 

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Discussion Starter · #52 ·
Hey IamIan,

Those are brushed DC motors. Would anybody think they would be efficiency winners in your contest?
Hey Major,

Probably not many ... I myself did not expect it ... but to be fair I want to at least look at the published specs first ... I did not want to just rule them out without even looking at the data... and it was at least close to a specific motor and controller suggestion ( even if I don't think it was a serious suggestion ).

They have other traits for other considerations not related the efficiency being looked at here... nothing wrong with that at all.

And the Solitron likely does have higher peak efficiency than your favorite rival because it has a single switch in series with the load. So what? They don't advertise it because it really does not matter. Hell, a contactor controller has the highest efficiency.
I have sent a email ... hopefully they do have and will provide an efficiency performance curve ... without that data ... I do not feel justified automatically declaring them or anybody to be more or less efficient than anybody / anything else.

What motor would you combine with the contactor controller in order to yield better combined efficiencies ... peak efficiencies ... or nominal / average efficiencies over the motors operating range? ... after all the 'contest' / 'question' ... is for a combination of a specific motor + a specific controller... what specific contactor / contactor controller were you considering?

As far as it ... 'really doesn't matter' ... as said many many many times ... I/we recognize efficiency is not the only determining factor for real world component selection ... etc ... etc... etc... but for here it is the question being asked.
 

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Discussion Starter · #53 ·
And the Solitron likely does have higher peak efficiency than your favorite rival
Had a nice email exchange with Jeff about Soliton1.

They do not have , publish , or offer any efficiency graphs for the product... that was a bit disappointing. :( ... of course their reasoning is sound ... Customers don't asked for it , and it would require several graphs to accurately represent different operating conditions.

However they do claim that in the worst case it is still over 98% efficient.

Which does put it up as the best average overall operating range efficiency ... other controllers might be able to match it at some points , but all that I have seen have significant portions of their operating range that are bellow 98% efficiency.

Which means the only remaining piece needed for the combination is a Soliton1 compatible motor that does not pull the combination down bellow the lead the Soliton1 offers.

I haven't bumped into one yet ... if anyone knows of one, please post. :D
 

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Discussion Starter · #55 ·
I don't think it's possible for a series brushed motor.
That's what I've been seeing ... that even though the Soliton1 controller itself is very efficient ... it is not enough on its own to carry the lower efficiency I have been seeing in compatible motors... to have combined efficiency that is still competitive , with the other contenders ... for this inquiry / thread topic. anyway.
 

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Hey IamIan,

Those are brushed DC motors. Would anybody think they would be efficiency winners in your contest?
major
I was at a manufacturing show in Toronto a few weeks ago. One booth had this solar powered electric "car". I came back a few hours later to meet and talk with the guy who built it and drives it. He has several current world records and has even driven it to the arctic circle. Running off midnight sun.... wow. Anyways, his quest was for the most efficient components. What kind of motor does he use?? Brushless DC Wheel Motor. ;)
 

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.... and Ian has tried many times to keep the thread focused on what he asked. The attempts to change the intent have been relentless...:p:p (way to go Ian:D... I find this actually very interesting)

as for moving an EV around at high efficiencies.... I dunno man, I would imagine that there are more BLDC motors moving more folks around in their respective EVs than any other motor. Every electric bicycle (and there are millions of them) has one. :p
 
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