Air Cooling my x5

[potatonet]

think about how a turbo works.

thats why its suggested that way.

http://static.howstuffworks.com/gif/turbo-parts.gif

[Vim]

I don't know if this would work, but... what if the stator spokes where shaped like fan blades and the left side axle was drilled out or key cut just like the right side for the wires... and the fan blade stator spokes drew air through the wiring side axle hole and pushed the hot air out through the left axle hole? The right side axle hole (intake) would point forward, and the left side axle hole (exhaust) could point towards the rear. Maybe not feasable for the home modder, but good at the manufacturing end? ...if it worked.

[potatonet]

I would seriously look into manufacturing glue on plastic scoops for predrilled holes on these.

there might be enough demand to warrant the cost of even manufacturing two different ring sizes in the same mold. I think there are enough machinists here. just need a machine to run the injection for the mold.

or if someone can think of something else... like this

http://www.oocrcracing.com/Label%20-%20LP.jpg

air scoops for RC cars or RC planes



Vim,

remember the stator is static, the covers move and the rotor move.

[Almasi]

I would seriously look into manufacturing glue on plastic scoops for predrilled holes on these.

there might be enough demand to warrant the cost of even manufacturing two different ring sizes in the same mold. I think there are enough machinists here. just need a machine to run the injection for the mold.

or if someone can think of something else... like this

http://www.oocrcracing.com/Label%20-%20LP.jpg

air scoops for RC cars or RC planes



Vim,

remember the stator is static, the covers move and the rotor move.

Better than that...get a mold and make some in aluminium casting with the scoop built-in to them...it would be a simple job of swapping cover!

Robin

[Vim]

Vim,

remember the stator is static, the covers move and the rotor move.

Doh! I swear I knew that but it just escaped me when I thought that up. I gotta cut down on the paint huffing.

Okay then... the inside of the side plates had spiral webbing to act like fan blades? Ehh, stupid idea

[markcycle]

I don't know if this will work for the X5 but I'm working on this for the 602. It might work on the X5 with a redesign of the side covers. The holes in the side covers will have screens and maybe a epoxy encapsulated windings.

Mark

[Zoot Katz]

It seems to me that if properly formed stiffening vanes were applied in opposite directions on the inside of the cover plates, one side would suck air from outside and the other suck air from inside the motor. No?

[markcycle]

It seems to me that if properly formed stiffening vanes were applied in opposite directions on the inside of the cover plates, one side would suck air from outside and the other suck air from inside the motor. No?

If designed right it will work. The thing is If your stopped at a light there will be no cooling. The problem with these motors are they produce the most heat at starting from a stop at low RPM's. So active cooling should work better especially in stop and go traffic.

Mark

[potatonet]

you are going to put 40W of fans in there?

you think thats gonna help you more than it hurts your battery?

this is the point of air cooling.

[vanilla ice]

Vintage race bikes, thats the closest thing I've seen to this. Works well for those guys.

[markcycle]

you are going to put 40W of fans in there?

you think thats gonna help you more than it hurts your battery?

this is the point of air cooling.

That's the point to the experiment, but I think yes. We are talking drag racing bike, motor to the max. BTW the lights on my motorcycle are a 100 watts 150 with the brake light. I'll burn 40 watts anytime to avoid thermal shut down and wait on the side of the road for a half hour for it to cool off. The fans can be thermally controlled to turn on at a certain temp. If most of your heat is generated at startup, what other choose is there ( if your committed to a certain motor)? BTW I have 4KW of battery in my bike.

[potatonet]

well then I think you are set, Im only rolling 1.25kw right now so 40 watts is something to take note of

[tostino]

well then I think you are set, Im only rolling 1.25kw right now so 40 watts is something to take note of

Well it depends on how much the lowered temperature increases motor efficiency. There is a pretty good chance that lowering the temp will affect the motor in such a way that it completely out weighs the power your spending on active cooling.

If you are pushing 3000 watts to your controller, and your motor is running at 82% efficiency, you are getting 2460 watts going to motion, and 640 watts wasted as heat.
And again, if you are pushing 3000 watts through your controller, 40 watts in active cooling fans, and that increases your motor efficiency to 84%, you are than getting 2553 watts as forward motion, and only 446 watts as heat (with 40 being used for cooling).

[markcycle]

well then I think you are set, Im only rolling 1.25kw right now so 40 watts is something to take note of

Well it depends on how much the lowered temperature increases motor efficiency. There is a pretty good chance that lowering the temp will affect the motor in such a way that it completely out weighs the power your spending on active cooling.

If you are pushing 3000 watts to your controller, and your motor is running at 82% efficiency, you are getting 2460 watts going to motion, and 640 watts wasted as heat.
And again, if you are pushing 3000 watts through your controller, 40 watts in active cooling fans, and that increases your motor efficiency to 84%, you are than getting 2553 watts as forward motion, and only 446 watts as heat (with 40 being used for cooling).

Well said. Those of us that have used a X5 to it's extreme know the increase winding resistance due to temperature reduces performance or as you said efficiency, to the point that there is a noticeable performance hit. If active fan cooling can reduce this effect enough by maintaining a lower wire temp then its worth the watts.

Mark

[John in CR]

Steveo,

Don't forget the side covers also support all the weight, and the metal quality is suspect, so if you weaken them with holes I'd add back some kind of support ribs. If on the interior the ribs could take the form of the vanes previously mentioned, and stimulate a turbulent air flow near the windings where it's needed.

Considering the fabrication effort involved in creating effective air cooling at the low rpms of hub motors I'd recommend a liquid cooling approach that has the potential to be far more effective for cooling and keeps the motor sealed. Plus I think everyone wants to see a liquid cooled high powered hubby.

If you're stuck on air cooling, I'd first try without vents. Instead try some interior vanes to both add interior surface area and create a turbulent interior air flow. Then increase the surface area on the exterior as well with fins or a large disk on each cover.

John

[vanilla ice]

I'll wager just drilling some holes would get 75% of the way to the cooling of the full ducts and ribs and fans treatment.

I'm at a loss trying to think up a good internal retention system for small filters. Maybe something that clips in to the round holes, that way you wont need to worry about it.

[potatonet]

if there are no holes then the air is going to remain stagnant. you need a hole...

liquid cooling would be great, anyone thinking about making a custom axle that has really large threads and no stepdown?

then you could probably get away with running the liquid in down the center of the axle and into some custom radiator/s inside the wheel then back out the other side.

it really would not be hard if I only had a decent CNC mill...

Im thinking about making my own stator for my next motor because these CL ones suck donkey huevos.

next time I will use strain hardened aluminum pressed into stainless and then wound with copper (just got to get back home)

[stew007]

This is how I did my 408, I run over 2000watts through this motor without it over heating. Before I drilled the holes, it over heated and lost power after only a few miles, efficiency took a big hit too. Now it behaves like a totally different beast fresh crisp power on tap all the time, after a 20 mile ride the motor is just slightly warmer than ambient to the touch, before drilling the holes it was scalding. I've done over 500 miles now without a problem, no problems of dirt, but I guess I dont really use it during rainy days, but if you could get a few weep holes close to the outside of the can then I would think any moisture would exit at speed, so not be much of a problem. The benefits so far have been huge, from a 600w motor to a 2000w motor

ps, I counter sinked the holes on the outside, so the air friction on the outside of the plate draws the warm air out, a bit like a venturi. This was done on both sides of the motor.

[vanilla ice]

One guy's swiss cheesed motor is worth 1000 posts.


I bet I could do that without removing the side plates.

[Almasi]

This is how I did my 408, I run over 2000watts through this motor without it over heating. Before I drilled the holes, it over heated and lost power after only a few miles, efficiency took a big hit too. Now it behaves like a totally different beast fresh crisp power on tap all the time, after a 20 mile ride the motor is just slightly warmer than ambient to the touch, before drilling the holes it was scalding. I've done over 500 miles now without a problem, no problems of dirt, but I guess I dont really use it during rainy days, but if you could get a few weep holes close to the outside of the can then I would think any moisture would exit at speed, so not be much of a problem. The benefits so far have been huge, from a 600w motor to a 2000w motor

ps, I counter sinked the holes on the outside, so the air friction on the outside of the plate draws the warm air out, a bit like a venturi. This was done on both sides of the motor.

Nice to hear this from someone who did it

I guess I know what to do next

Robin

[steveo]

This is how I did my 408, I run over 2000watts through this motor without it over heating. Before I drilled the holes, it over heated and lost power after only a few miles, efficiency took a big hit too. Now it behaves like a totally different beast fresh crisp power on tap all the time, after a 20 mile ride the motor is just slightly warmer than ambient to the touch, before drilling the holes it was scalding. I've done over 500 miles now without a problem, no problems of dirt, but I guess I dont really use it during rainy days, but if you could get a few weep holes close to the outside of the can then I would think any moisture would exit at speed, so not be much of a problem. The benefits so far have been huge, from a 600w motor to a 2000w motor

ps, I counter sinked the holes on the outside, so the air friction on the outside of the plate draws the warm air out, a bit like a venturi. This was done on both sides of the motor.

now thats what i'm talking about

-steveo

[potatonet]

I will be doing this to a motor sooner or later, good job,

I never though about drilling on the edges! that would provide the scoop!

[Zoot Katz]

. . .

ps, I counter sinked the holes on the outside, so the air friction on the outside of the plate draws the warm air out, a bit like a venturi. This was done on both sides of the motor.

now thats what i'm talking about

-steveo

Drillium? What are you, a weight-weenie all of a sudden?

You need a radiator, pumps and yards of tubing.
Play for the complications.

[potatonet]

. . .

ps, I counter sinked the holes on the outside, so the air friction on the outside of the plate draws the warm air out, a bit like a venturi. This was done on both sides of the motor.

now thats what i'm talking about

-steveo

Drillium? What are you, a weight-weenie all of a sudden?

You need a radiator, pumps and yards of tubing.
Play for the complications.

please explain this whole post, as it made no sense

[dogman]

Thanks for the real world, I tried it and it worked, post. I think even some fine screen would keep enough of the dirt out. Just something to keep the rocks above .5 mm out. Some clay powder on the coils won't hurt, and the bearings are sealed.
For those using a bit less power, less holes might work fine.

On my aotema motor testing, I will first simply try to melt it, riding in 100F temps for 500 miles or so. Then if it survives, I will see what the effect of more and more air holes is, to find the smallest practical vent hole for normal 36v operation in the desert.

I wouldn't want to risk hundreds of dollars to avoid popping the covers, it's not that hard, so take off the cover to drill.