Cooling Ideas For Those Running Brushed or ROAR Motors

[Meniscus]

So, I've been running ROAR motors in a few different models for some time now. Recognizing that we cannot use a traditional water cooling jacket because the motor can is open, we are currently relegated to using a coil, a silicone jacket, a heat sink or one of the newer liquid cooling covers which are showing up on RC cars.

In my experience, the silicone jacket doesn't help much. The standard coil is another option, but doesn't have a great effect since there's so little surface area touching the can. Water cooled motor mounts help a fair bit, but still leaves something to desire.

Here's the idea: What if we were able to find somewhat flexible square copper tubing that we could use to create an improved coil that has more contact area with the can?

I haven't tried to source smaller sized square copper tubing, but it is something to consider for those who run these motors.

In my boats running the ROAR power plant, I have used the combination of a water cooled motor mount and a heat sink which sits snug against the can. Does anyone have any better ideas?

[785boats]

I had good success with the coils when a lot of electronics Heat Transfer paste was used with it to fill in all the spaces between the coils & the cans.

This type of thing works pretty good too.
https://www.banggood.com/Alloy-Heat-...r_warehouse=CN

[30nitro]

If you source the square copper tube....let me know...Have a similar situation.....Thanks...

[NativePaul]

I used to pull fairly hard on the (round) alloy tube as I was wrapping it around the mandrel, that would flatten the bottom of the tube. There is a bit of trial and error to discover how hard to pull so as to have a good effect without crushing it too much, and what size mandrels to use for a tight spring fit (iirc it was a 35mm film can tub size for a 540 motor), but when combined with thermal compound it can be very effective indeed.

I still know folks using coils on brushless motors as while the thermal path isn't so good, it does guarantee that the whole can is cooled and who knows what is going on inside a commercial jacket, there may be stagnant areas that are.effextively getting no cooling.

[785boats]

If you source the square copper tube....let me know...Have a similar situation.....Thanks...

I have some square K&S aluminiun tube. Maybe they do brass or copper too.

[TRUCKPULL]

Contact Dave at;

http://hrc-mfg.com/

He makes the motor coolers here for Offshore Electrics
He has made many custom items, cooler and more for me in the past.

Larry

[kfxguy]

Couple ideas. Use some foil tape, wrap around the motor. Over lap it a little. Slice it with a razor. Fill the tiny seam with silicone. Slide jacket over.

Or, do the same thing with super thin copper shim.

Or have a thin sleeve machined out of aluminum. Slide on can. Use a touch thinner orings and slide the cooling can on. Same thing with the above other two ideas.


What parts are exposed on the motor? The cuts that locate the magnets? Fill those neatly with jb weld. Get a short jacket that won’t cover the slots by the brushes.


Have some jackets machined that are enclosed on the inside.

Just some ideas.

[Meniscus]

Great suggestions guys. For ROAR motors, the silicone may be an issue as the motor will need to be inspected. Regarding the open areas on the motor, provided below is a picture. Please note that every ROAR motor looks a little different, but will feature many of the same open areas.

< Please note that this is an example pic. In no way am I using a 8.5T motor, just to be clear. I just grabbed a pic from the web to demonstrate the point.

Regarding the current heat sink I use, provided below is a pic of one that is very similar to what I use. I don't think I have room in my models for a fan on top, to the side or along the same axis as the motor.

[eric113]

I don’t really see the point of the aluminum fin heat sink in a boat.Since going be inclosed? They made to have open air moving.

I think cooling tube coiled and fan will be your best bet.

[Speed3]

Put tape over the hole.

Get a jacket that is suitable length and slide on.

When its time for inspection you can slide off the jacket and untape the holes.

Only precaution is that when you are sliding on the jacket the tape covering the hole don't come off.

You can practice sliding on the jacket so the tape don't come off.

[Meniscus]

I don’t really see the point of the aluminum fin heat sink in a boat.Since going be inclosed? They made to have open air moving.

I think cooling tube coiled and fan will be your best bet.

I have tested both ways, with and without the heat sink, even in a rigger. With the heat sink, the motor does stay cooler than without.

[Meniscus]

Put tape over the hole.

Get a jacket that is suitable length and slide on.

When its time for inspection you can slide off the jacket and untape the holes.

Only precaution is that when you are sliding on the jacket the tape covering the hole don't come off.

You can practice sliding on the jacket so the tape don't come off.

The trouble I see with tape is that it will melt or get stuck to the motor. Also, at speeds above say 35mph, I would venture to guess that the water pressure would become an issue on the edges of the tape. Plus, I can't imagine trying to slide the o-rings over the tape and having any confidence that the tape would still hold. If it doesn't, then you'll end up pumping water into the inside of the boat. The electronics will run until everything is submerged.

Along these lines, I have considered putting heat shrink over the entire motor, but I have not tested and do not know if the heat shrink will just meet at higher motor temps. I would also think that it would insulate the motor and possibly make it hotter all the way around.

Keep the ideas coming guys!

[kfxguy]

Put foil tape ove the whole can where it protrudes past the cooling can. Easy.

You don’t epoxy coat your electronics? I learned when I first started doing this that 1) parts are too expensive to let them get ruined 2) accidents happen 3) it’s cheap and easy insurance. There’s no good reason not to epoxy coat everything.

[rol243]

Yes try taking apart a Turnigy 180 esc. all set in epoxy.

[Meniscus]

While conformal coating is a good practice, the roar motors I run for some of the records feature sensors. It is very difficult to find a compatible waterproof ESC, meant for boats, that can properly handle the sensored motor and operate correctly without a lot of excess heat. When you couple that with the fact that there is an on board sensor circuit on the roar motor itself, it is essential that everything remains dry.

All of my boat ESCs are protected from water and even when I use old ESCs meant for airplanes in my small riggers, they are conformal coated as well.

I admit that the foil idea is a good one. The main issue I have with that idea is the matter of the seam. Most any adhesive will break down at high temperatures. Those that do not are permanently affixed and do not allow for removal for inspection of the motor.

A tight fitting metal sleeve could work. We would just need to have the seam be fail proof. Even solder will melt if there's too much heat.