Mineral oil inside hub motor

[KristianW92]

Hi all, im new here.
I was thinking about filling mineral oil into my hub motor to help with thermal conductivity this was more as a quick solutions. Because its a mag wheel hubsinks aren't an option.
Im away that mineral oil is non conductive so im not worried about that and it also has a high flash point so im not worried about flames either. However my main concern is if it will damage the hall sensors in any way? Like if its able to seep into them and stop them from working.
Also the bearings may benefit from having continuous oil if i was too removed the inner seal as you would on a 2 stroke engine.

 

[neptronix]

Might want to check this thread.. lots of discussion of various cooling mediums.

Oil cooling a motor with transformer oil/dielectric fluid - the next frontier?

 

[AGS]

That’s a long thread and difficult to wade through.

I oil cooled a Bafang SWX02 motor rated at 500 watts and have run it for well over 1000 miles at over 1500 watts and it’s holding up well.

I used around 75ml of ATF. It doesn’t need much oil.

I have also fitted a temperature sensor inside the motor. I can run it flat out constantly at 1500 watts and the motor temperature stays below 90C.

I tested the motor without oil before hand and it overheated in around 15 minutes. Which is exactly what the Grin simulator said it would do.

I sealed the axle using high quality loctite flange sealant, although one day during the summer heat I did get some oil on my brake disc. And oil leaches through the wiring into the motor connector and I have to clean that periodically using switch cleaner when it fills up and causes bad contacts.

So it has its upsides and downsides.

My conclusion is oil cooling allows me to run my motor at over 3 times its rating and it is difficult to keep the oil in the motor.

Oil won’t leak into the hall sensors, so don’t worry about that.

I have sealed bearings, so they don’t gain any benefit from oil cooling. If yours aren’t sealed then the oil will not stay inside the motor.

 

[KristianW92]

Thankyou! I have all the answers i need

 

[Chalo]

Because its a mag wheel hubsinks aren't an option.

I think you're trying to say that your entire wheel is a heat sink. That's a point in favor of cast aluminum and magnesium wheels, despite all the points against them.