[WheelMotor]

Originally Posted by _GonZo_

I been using a lot of RC Brush-less motors and controllers for quite long time, usually they are quite good quality motors and very efficient for the porpoise they are made, that is moving propellers or small RC cars.

The efficiency is achieved because they are made with very light and open housings for cooling, thin plates on the stator in order to minimize looses, and small ball-bearings in order to save weight.
But this type of motors will not stand continuous work as they will have to do on a car unless they are modified.

As well you have to know that the power rating of RC motors and controllers is not the same as industrial ratings, with this I mean that if an RC motors is rated to give 1000W means that is able to give up to 1000W for some seconds (about 10s usually) same for the controllers.
Usually when we install RC controllers if the motor is able to pull lets say 30A we instal one that is able to give up to 50A or more and usually modified with more heat-sink added to them.

The ball-bearings on RC motors are replaced every 20-30 hours of use.

Thanks for sharing your experience. We can learn from the RC motors.
I am trying if I can not get one of the Chinese motor lamination factories to sell me a stator that they already make in big volumes for an other client, to serve as the base for a BLDC design. Now that we are no longer constrained to the limited space inside the Wheel, we can also use cheaper magnets that are more bulky for the same power ...
If we combine all we learned so far, we could come up with a cheap compact liquid cooled BLDC that delivers enough power and RPM.

If somebody could help us out with following dilemma:
We are able to model a BLDC inrunner (with an outside diameter of 400mm and a stack height of 400mm too) that can produce 100Kw, but ...
We seam to have to choose between torque and RPM.
But we want lets say 500NM at 1000 RPM and 100Kw at 3000 RPM
We are of course limited by the Battery Voltage. When the motor spins fast, it produces high back emf, that counters the battery voltage and prevents high current. So for high RPM we need mucho Volt !!! and that is expensive. But than ... the RC motors turn at 40.000 rpm with only 40 volt.

[WheelMotor]

Before the trial ended I could still do this modeling:

it is a 60KW motor:




If we make this motor liquid cooled and with the proper bearings etc, we can have a compact usable motor for our application. Will investigate lamination or ready to wire iron motor parts from this motor starting. It has ferrite magnets. Price is very important, because expensive efficient super BLDC's are available, but not affordable
160 Volt battery and 600 amps. If we stay at 100 volt, we can not get sufficient RPM. I hear Major already thinking: 160 V and 600 amps is not 60KW. At max RPM the motor does not pull max amps, because of the controller settings and back emf. But we need the 600 amps to make at lower RPM the torque curve flat enough. Than with lower volt. The controller must limit the amps when needed, to spare the batteries.

[major]

Originally Posted by WheelMotor

But than ... the RC motors turn at 40.000 rpm with only 40 volt.

PM motors essentially have a constant flux, Φ. And the motor has a machine constant (sometimes called the torque constant), Kt. The developed torque (Tem) = Kt * Φ * Ia where Ia is armature current. The generated voltage (Eg) = Kt * Φ * ω where ω = rotational velocity. The machine constant Kt is essentially the number of turns. For the particular PM motor, KtΦ is fixed and torque is proportional to current and voltage to speed.

So the little toy motor has a small value of flux and few turns therefore a small KtΦ resulting in a low torque per ampere and high RPM per volt.

[_GonZo_]

I know that the idea to use Wheel Motors is very attractive for electric vehicles due its simplicity. And actually they work very well on bicycles because they are very efficient vehicles.

Normal street cars are everything except efficient (Too heavy and bad aerodynamics) so I do not think that Wheel motors are the best solution for a conversion. May be as commented here they will be enough for a hybrid conversion.

Anyway my opinion is that Wheel Motors will be on future electric car as soon as we have produce lighter and much more efficient cars, that will happen quite soon, energy and raw materials crisis is hitting all society levels already...

Technically talking I suggest for a DIY Wheel Motors to use industrial torque motors (quite big diameters and high poles count)
In order to give you some help I have been looking on some motors manufacturers and I think I have found some that will meet the needs of an electric vehicle.
This company provides them without housing so, if you have access to a good metal workshop will be not difficult to make the appropriate housing.
They are in-runners witch is very good because will simplify the cooling, actually I think if the motor is well matched to the duty (oversized) then only air cooling will be enough.
Link: http://www.alliedmotion.com/Products....aspx?p=10&s=1

Looking into the list I think the model MF0410015B with around 30Kw peak power and 325Nm peak torque will do the job.

Although as I commented before I think that this motors will work really well on a light and aerodynamic car but not sure if they will perfrom really well on a normal street car.

Hope it helps.

[PStechPaul]

Very good link. I wonder how much such motors cost?

I am still cheering for AC induction motors and switched reluctance designs because of various factors, but chiefly simplicity, ruggedness, and low cost.

[WheelMotor]

Originally Posted by _GonZo_

This company provides them without housing so, if you have access to a good metal workshop will be not difficult to make the appropriate housing.
They are in-runners witch is very good because will simplify the cooling, actually I think if the motor is well matched to the duty (oversized) then only air cooling will be enough.
Link: http://www.alliedmotion.com/Products....aspx?p=10&s=1

Looking into the list I think the model MF0410015B with around 30Kw peak power and 325Nm peak torque will do the job.

Although as I commented before I think that this motors will work really well on a light and aerodynamic car but not sure if they will perfrom really well on a normal street car.

Hope it helps.

Difficult to find out what the motor really does. (Motor 25, because no graph of 15) has only 109NM at 600 RPM at 150 Volt on the graph. But in the text they claim from 129 continuous to 529 demag torque (we don't want to demagnetize the motor, so this number must be avoided) Or do I misunderstand the graph ? That would be 6 to 10 Kw without gearing ? Not ok for my 1800 Kg Jaguar. Do you have the price ?


Like you say Gonzo, cars should be light, but as long as there is not a ban on GM Silverado's and ford F's I don't want to drive on the same road with a with a super light Loremo. It is on the government to impose a maximum weight for cars. But I don't see that for the near future.

[Nathan219]

I have been thinking torque motors for some time now, but I would not use them as a wheel motor but a direct drive motor. High pole count allows them to make significant torque at low RPMs needed for direct drive. Future vehicle technology used direct drive axial flux motors on their Evaro car in the Xprize. FVT built their motors themselves anyone with the right machine skills can make these motors. http://www.phasemotorparts.com i bet many of the motors we buy actually come from this companies parts. If anyone has a torque motor designed for 20-40 kw and 600-800 rpm we reverse engineer it, and build a copy of it with the parts from this company, and save time.

[_GonZo_]

Sorry I do not have prices, just made a big search on torque motors and those ones where the ones that looked to me more adequate for the job. They have office on UK and Germany, so just make them a call and ask.

You can download more detailed info, on last pages you have more graph:
http://www.alliedmotion.com/Data/Doc...egaflux_V2.pdf

[Dean125]

Very interesting post i must say, good luck on finding some affordable solution i cant wait to see the end result... just to give some ideas read an article of a MTSU professor Dr Perry making a very affordable plug in hybrid kit that will cost around $3000 WOW that is great but its not so strong to be autonomous it is intended to help the car engine and thats fine cos he says it can save you from 50-100% on petrol or diesel, here is the link from the article http://www.foxnews.com/leisure/2012/...ee-university/ or watch the video http://youtu.be/uOA_i2qAQq0
Also here is another website for interesting concept of in wheel motor, look at the pic http://evworld.com/news.cfm?newsid=25224
Good luck guys i hope you find some solution that its going to be affordable and make the car totally electric so you can choose between car engine and in wheel motor when you are driving!

[major]

Originally Posted by Dean125

Very interesting post i must say, good luck on finding some affordable solution i cant wait to see the end result... just to give some ideas read an article of a MTSU professor Dr Perry making a very affordable plug in hybrid kit that will cost around $3000 WOW that is great but its not so strong to be autonomous it is intended to help the car engine and thats fine cos he says it can save you from 50-100% on petrol or diesel, here is the link from the article http://www.foxnews.com/leisure/2012/...ee-university/ or watch the video http://youtu.be/uOA_i2qAQq0
Also here is another website for interesting concept of in wheel motor, look at the pic http://evworld.com/news.cfm?newsid=25224
Good luck guys i hope you find some solution that its going to be affordable and make the car totally electric so you can choose between car engine and in wheel motor when you are driving!

Hi Dean,

Nice to see you post again after 4 years. The MTSU joke was discussed back starting on post #233. And the other article is one and half years old containing the same old same old. Where are those 1000 wheelmotor cars to be made in 2011? And 100,000 by 2013

Regards,

major