hydro-one wrote:if your going though all the trouble to liquid nitrogen cool, may as well use a high temperature superconducting coil too
im rooting to discover one that works at room temp. solve all our problems.
dfar wrote:Just wanted to state that I tried the ATF cooling method and am really impressed with the results.
Before the introduction of the oil my HS3540 would get up to 90 Celsius +++ within 15min of heavy riding. With the ATF I cannot get the temp over 55 Celsius with full throttle riding. Overheating is now not the limiting factor in the performance of the bike.
I did not drill any vent wholes in the hub motor and sealed the sides with silicone. It seems a small amount of ATF leaks out through the bearings and axle and onto the sprocket. This unintended leak effectively "oils" the chain therefore I don't really have a problem with it.
The only thing I am thinking about altering is drilling and tapping a filling valve so one could top up the ATF without taking the side cover off the bike. Maybe make it into a filing/venting valve.
sounds good! what sort of power levels are you running/what size wheel? and when you say heavy riding, do you mean riding WOT lots with no pedalling?
dfar wrote:It seems a small amount of ATF leaks out through the bearings and axle and onto the sprocket.
bobale wrote:dfar wrote:It seems a small amount of ATF leaks out through the bearings and axle and onto the sprocket.
Wait a second. Bearings are usually greased with thick grease. How will introducing light oil affect their life? Will ATF wash off thick grease, and leave bearings dry if you decide not to put any more oil into the motor?
Burtie wrote:Seal both covers and the axle slot.
Drill the vent hole opposite side to the disk, close to the axle, just big enough to insert the aerosol tube (perhaps 2 or 2.5mm diameter).
I think it probably best to drill a separate filler hole big enough to sensibly inject the oil with a syringe (maybe M3 or M4), thread it and fit a bolt with an 'o' ring under the head, to seal it.
Position the filler hole to make sure the protruding bolt head will not interfere with the derailleur or the disk brake caliper.
Yes, the resonant audible buzz I experienced, seems to be attenuated significantly by the presence of the oil.
I am still amazed at how well this oil bath mod cools the windings, removes all the 'temperature anxiety' from my hub motored ebike riding
Thanks to bigmoose for bringing this technique to our attention at ES.
- Seal covers and axle slot with what sealant? Anything specific that can endure exposure to ATF oil?
- Where to get something like the aerosol tube?
- Should you protect the windings / hall sensors from exposure to the oil with something? Is the (low) conductivity of the oil not a danger to the electrical function of the motor / hall sensors?
- Would this also work with cooling a controller?
Thanks very much!!
hjns wrote:Therefore, my question is why one would cover the windings with the special epoxy?
dfar wrote:anyway when I opened it up there was still a lot ATF oil left inside, less than what I put in
parabellum wrote:dfar wrote:anyway when I opened it up there was still a lot ATF oil left inside, less than what I put in
Where is most of your oil coming out? I am riding over 1 months (not everyday) and have a feeling I only lost few droops. Am I underestimating oil loses?
P.S. My MXUS has hole trough axle center not groove like yours. Thanks for your review and hope you fix it soon!
bigmoose wrote:I sure hope you will stick with air cooling. This will give the rest of us time to surpass the performance of your monster motors!
Farfle wrote:I need to go thrash it around and get a screenshot, but the air cooled doublepie with my inexperienced 200 pound self has exceeded 200wh/mile average on the socal racetrack, it did overheat but not to the point of destruction, The temp sensor did pass 190C (thank you 220C rated wire ). BUT about 1KW of the heat its making is iron losses due to a construction error, so when I get in two more pies ill have to do another test.
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