Re: Protean’s high torque in-wheel motors
Posted: Mon Dec 27, 2010 10:50 pm
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I knew there would be some example, however you would have to take into account that brakes can put about 4 times more strain on drive shafts and CV's, failure is more likely at the front as a result and failure at the front can be catastrophic.Keith Morganstein wrote:Oh, some lovely cars such as Citroëns and the early 70's Audi 100 had inboard front disc brakes...RobsonCNC wrote:Probably for the same reason that you don't see many(or is that any?) cars with the brakes mounted inboard. I know it's been done at the rear though, but not sure of the front.
If I used the unit converter correctly, one of the motors listed here http://www.printedmotorworks.com/in-wheel-motors/ can make over 550ft lbs but it seems odd to me that it only has about 1/10th the Horse Power. It would have been nice if they listed some dimensions.dieselgeek wrote:I worked on a project that used prototypes from this same company in an F150 pickup truck as a demonstrator for a hybrid vehicle.
These motors were capable of around 400 ft-lbs of torque at the wheels, flat curve and impressive (i.e., not just 400 ft-lbs at zero rpm)
Specifically, what do you mean by ruined? Did the rotor flex or bend?dieselgeek wrote:However the major obstacle was that the motors were quickly ruined as soon as the vehicle hit even the slightest of bumps at any kind of speed. They're still working on that problem, last I heard. It's been about a year since I've had any updates though.
The ratings on the website may be continuous, while the bragging point for vehicle use is a "transient" rating for the 0-60 sprint. Just like a gearbox, cooling is the factor that determines maximum power throughput over time for an electric motor.Brian S wrote: If I used the unit converter correctly, one of the motors listed here http://www.printedmotorworks.com/in-wheel-motors/ can make over 550ft lbs but it seems odd to me that it only has about 1/10th the Horse Power. It would have been nice if they listed some dimensions.
PMW XR 20-12
Rated Torque 25 Nm=18.44 TQ
Rated Power 1.2 kW=1.61 HP
PMW XR 32-12
Rated Torque 203 Nm =149.71 TQ
Rated Power 23.4 kW=31.38 HP
PMW XR 44-16
Rated Torque 753 Nm=555.31 TQ
Rated Power 47 kW=63.03 HP
And if you experience a suspension failure under hard braking, you'll be in a world of hurt, too.Brian S wrote:I agree, but the forces will be transferred through CV joints and half shafts. If there is a joint or shaft failure during hard braking you may lose control, especially if it's a front wheel. Inboard brakes will use a smaller diameter rotor than can be mounted outboard so more clamping force is required.The Dark Side of Will wrote:If the brakes are mounted at the hub, then the suspension has to deal with brake torque as well as the longitudinal force slowing the car.
With in-board mounted brakes, those forces can be separated.
Interesting.The Dark Side of Will wrote:.... Cat has just come out with a diesel electric bulldozer.
On other sites they usually state continuous and peak torque numbers separately but they are usually about 10x the difference so that would make sense. I'm reading about some cooling issues and I think one guy was saying that over 150 degrees is enough to destroy the magnets. That sounds like a good reason to keep them some distance away from friction type brakes.The Dark Side of Will wrote:The ratings on the website may be continuous, while the bragging point for vehicle use is a "transient" rating for the 0-60 sprint. Just like a gearbox, cooling is the factor that determines maximum power throughput over time for an electric motor.
Suspension is a necessary evil for 99% of all vehicles and has to be strong enough to support the vehicle weight in all directions including rotational forces. It should be easier to control these rotational forces when the pivot points are spaced far enough apart. An axle or half-shaft has to control the spinning mass from the center... correct? Don't these parts also contribute 50% to the unsprung weight?The Dark Side of Will wrote:And if you experience a suspension failure under hard braking, you'll be in a world of hurt, too.
I shouldn't be surprised by this but they were talking about rising fuel prices on the news again today and one "expert" was saying $5 per gallon may not be far off.Jerminator96 wrote:I think we will see a lot of old ideas revisited as gas prices continue to rise and increased regulation forces the industry into a corner.