johnrobholmes wrote:I'm gonna have to give ATF a shot in one of my MAC hubs. Heck, i'll just drill one hole and see if it leaks out a stock motor.
andynogo wrote:ATF is a good choice for hubs as its cheap enough and easily available. Also easy to spot a leak being red.
andynogo wrote:johnrobholmes wrote:I'm gonna have to give ATF a shot in one of my MAC hubs. Heck, i'll just drill one hole and see if it leaks out a stock motor.
Oh, I soooo wanna see before and after photos of that, especially your clothes...
After you've done that you might want to seal those side covers up....
Kingfish wrote:I am saddened to learn of this thread though AFTER I had my hubs drilled to vent water. However, a small vent hole near the axle is still possible, and I like the idea that oil is sloshing around to keep moisture away from my delicate unplated stators. At least they will have varnish.
Good thread, good ideas; thanks guys – this is very useful!
John in CR wrote: I seem to recall that he tested it on DD's too, and the efficiency hit made it not worth it.
flathill wrote:John in CR wrote: I seem to recall that he tested it on DD's too, and the efficiency hit made it not worth it.
Do you recall why? Could the increased drag be that much of a hit? Remember the cooler you keep the windings the less losses....Your 93% motor wont measure 93% hot. Are you the same John from diyaudio?
fechter wrote:It should be much less significant on a direct drive motor as the velocity of the rotor is much slower.
flathill wrote:You bring uo some good points John from CR
The answer to all these thing is
You have guys in ev land swearing gearboxes are dead
But I dont see a future of big rig trucks carrying tons of cargo without gears or active cooling
I was just tring to bring up the point a cooler running motor is more efficient no matter the application
Passive cooling should have almost no downsides but you are right about oil seeping into the glue joints could be an issue depending on how they react
andynogo wrote:.....ATF is a good choice for hubs as its cheap enough and easily available..
fechter wrote:A somewhat simpler test would be to measure the no-load, full speed amps before and after adding oil. My guess is the oil will increase the no-load current quite a bit. There's no way it will make the motor more efficient, but will allow it to run at a higher power rating without failing. It would be nice to know exactly how much additional drag it causes. It may cause only a small reduction in range.
It should be much less significant on a direct drive motor as the velocity of the rotor is much slower.
Good! Someone finally oil cooled a hubbie!! HS3540
cell_man wrote:Interesting, I will have to try this myself. Now I have temp sensors fitted in some of the hubs it's easy enough to check and make comparisons.
BTW Andy, I have your new stator with the higher grade and thinner laminations and will get it out tomorrow. Would be interesting to see how it compares temperature wise compared to the stator you have are now using when run dry, but as this is a 10T and you are now running an 8T so not sure how that could sway the measurements.
Good stuff and food for thought, thanks
andynogo wrote:I agreee with alot of the comments John in CR makes. I did it as a bandaid- but can also see an application for pushing cheaper motors well beyond their thermal limits- especailly geared hub motors like the mac or bmc where they are an insulated oven if you try and put too much power through them (remembering they are rated at 500-1000W, not the 3300W I was putting into mine).
We can't all afford to get a cro or don't want a 16inch scooter motor etc, which can certainly handle alot more power without causing dramas.
This type of mod is simple, very cheap to do and can elevate our lower powered hub motors into a much more fun level of power. In my case it makes my bike rideable again until I fix it. Even then, because I have time and money invested in what I have, I may as well oil cool the new stator and see what I can get out of it. As long as I monitor temp at the windings it will be fine. When I get to that point, I'll do some fairly decent dry and wet measurements just for people's (and my) curiosity.
bigmoose wrote:.... So does anyone know a car that has had reasonable production volume that has very small planetaries in the transmission that could be repurposed?
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