[toddshotrods]

Originally Posted by major

I once worked on (tore apart and reassembled) an induction motor having coolant passages like you show. They appeared to be bored in a solid steel thick wall tube. It was slightly longer than the stator. Stator appeared to be heat shrunk pressed inside. No gettin' that sucker apart. Then the longintudinal passages were gasket sealed and headered (is that a word?---like a manifold:-)) off by the end bells themselves which had a single in and single out port.

Hope that made sense

major

It did, thanks Major - gives me even more ideas.

That's a nice looking motor in the pic you posted Miz!

[tomofreno]

Originally Posted by toddshotrods

Good points. We can machine the jacket and even turn the motor frame, but your point is well taken about the tolerances. One thing about that though - the chill plates people use on controllers can't have any better contact area, even if they're machined flat and they seem to work well enough?...

Depends on the amount of heat transfer required, surface finish and flatness (usually dealing with flat parts), the bolt pattern (lots of bolts to clamp the parts together if that is possible), and whether something like heat sink compound is used to fill gaps -which should be very thin so there is only a film of this filler since it usually is not as good of thermal conductor as metal. In some applications there is a seal between the two parts around the edge, and helium (low mass molecule for higher heat transfer) is injected in the gap (even one due to surface roughness only) to increase convection. I would guess a controller is greater than 95% efficient, whereas a motor is maybe 80% in racing conditions, so more heat to dissipate if you want to keep the case at a given temperature after it has reached it. But yeah, if you can get the surfaces to match closely, use heat sink compound, and clamp it tightly, I would think it would work fairly well - assuming the heat exchanger connected to the cooling passages can handle the load.

[JRP3]

Originally Posted by mizlplix

I still wonder about putting the tubing through a roller or something to flatten it out some and greatly increase the contact area compared to a round profile.

[mizlplix]

Copper is worse than most metals when cold worked. It gets "Work hardened" and must be annealed before it can be bent again. Cold working (either compression or stretching) produces a system of uneven stresses in the matrix and the material loses what elasticity it had. (The next time you bend it, it fractures).

I would use a common sheet metal bead roller to flatten copper tubing and then reheat it with a propane torch to anneal.

The wrapping could be done by hand as I did, or in a lathe.

If you want to go all out, I would sand the motor case and "Tin" the surface. That way you could heat and solder it as you wound it on the case. Of coarse, that would mean Stator removal.But it would conduct heat nicely.

A point was brought up that the water would heat soak in the first section and leave the last half of the motor hot. My air flow is encoder end to drive end. So, my water flow is drive end to encoder. (An attempt to even out the temperature slope in the motor).

Now we are to the point of a LOT of work and added weight.

Better to just machine yourself an aluminum motor case like Ivansgarage did.

In retrospect, My AC50 has a 120C maximum temperature. Water boils at 100C. My temps are running 60C area.

I am thinking that unless my temps reach 100C, I dont need water cooling.

At that point it would not cool the motor down, but it would slow or stop any further rise in temperature.

Miz

[mizlplix]

I would like to throw another water cooling subject on the table.

My controller.

Curtis 1238R with a custom cold plate made by Ivansgarage.

It is of the "Bath tub" design.

It uses the thermo-siphon principal. Cold liquid in at the bottom, warm liquid out the top in a natural convection manner.

Some say it is inefficient because there are "dead" spots with no flow.
Some say it makes the upper controller run hotter than the lower.
Some say it will corrode and ruin the controller.

All are valid points.

My thoughts:

it is inefficient because there are "dead" spots with no flow.

When a liquid is in a dynamic environment, it will react most at the point of greatest energy absorption. So while the complaint is correct, the liquid never really stands still.

it makes the upper controller run hotter than the lower.

This is partly true, but greater water volume is a good "Band-aid" to this glitch.

it will corrode and ruin the controller.

The heat and pressures in a conventional ICE cooling system does not exist here. Even then it takes years to do any real damage. But, careful addition of anti-corrosives will slow this down further. I am a proponent of the "direct contact" method of heat transfer.(Water contact) It is magnitudes more efficient than conduction alone.

So far, it is working really well. No leaks even when held by the 4 corner bolts alone. (Use a good anaerobic gasket compound-keep the surfaces flat)

I have about 2 GPM flow and am using a 50-50 solution of Propelyene Glycol.
It is cheapest from the Pet store. It is nice to work with and is environment friendly.

Miz

[swoozle]

What kind of pump do you use?

[Ivansgarage]

Hey Miz you didn't tell us what kind of temps your running on the controller..

[mizlplix]

My controller is running 48C with an ambient of 109F. Motor was 55C /water and 60C /air.

Remember- flatland, stoplights a mile apart, light weight vehicle.

The max temp rating is low for class H. (120C)
It should be able to run as high as 180C before suffering damage. Unless there is another reason besides insulation rating.....

Miz

[Ryan800]

I haven't seen it mentioned yet, so I just want to point out that copper pipes with an aluminum radiator is a recipe for galvanic corrosion. Use only one metal for the entire coolant loop, or expect to replace things sooner or later.

Also, if the coolant doesn't see high enough temperature it won't kill bacteria. I'm not sure how much of a concern this is in reality, but Tritium's controller manual points it out. There are biocides that can be added to the coolant.

[mizlplix]

Last time I looked under the hood of my F150, I had aluminum, brass, copper, stainless steel and cast iron, all in the cooling system. I guess that is why the coolant is so exotic...That or FORD does not read forums.

Seriously, My degree is in Metallurgy. In a pure chemical form, you are correct, but we all must replace things eventually. I just think of it as a standard maintenance deal. No liquid cooling system lasts forever. I try to not
"over think" the problem and accept 4 years between flushing and some parts replaced as normal, here in the alkaline South West, USA. (Other places get 5-10 years on theirs)

Miz