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if’n you look on the elofty thread my friend, you’ll see I’ve posted pix of inside the motor bell, and the magnets actually contact each other, there is NO gap between magnets… battle hardening eLofty’s magnets would be problematic…
Easy to balance a motor w a laser strapped to the axle of the skate truck or whatever; when the motor spins the laser spot on the wall will vibrate and you add material to the rotor adjusting till u get the laser spot close to stationary
Not reading it all but it seems with the iron filled glue it would be like the “f” simulation and shows worse than not iron filled. I head the magnet circuit is able to jump between magnets that way and not complete the full magnetic circuit you’d want going through the teeth
The hallbach for the win! If u strip the magnets out with acetone (hopefully) and put them back with the field shaping sideways magnets in but that’s not just battle hardening
Thanks… but WTF am I looking at…BTW you mention(ed) hallbech magnet arrays before… and until you GIFT me field shaping magnets, I’m afaiad it’s a little out of scope here…
fuck I wish I knew what you’re trying to get across with all those “shart” pix…
Look at it a long time and will become clear. Haha. No it’s not complicated and they did all the work.
Or read the paper on a couple choice pages with the charts I posted. They break down with the graphs the losses, torque n speed, efficiency…
But if you want to just do it anyway to compare if u end up with a lower kv it’s likely better.
I watched the first bit but he makes broad statements. It’s half hour long! But the grooves on the outside makes sense in that magnetic field comes out the side of the magnet and THATS where u want the thicker flux ring. The writing on the screen didn’t make sense n flux rings must be ferromagnetic. Or do hallbach n then u don’t need one. As far as magnet poles beside each other being bad not necessarily. For our purposes the greater magnet fill the better it seems. If u were gunna spin really fast w a drone for example ud maybe want them more spaced as it would be more efficient in having less iron losses maybe but we spin so slow on boards we don’t have almost any iron losses and rather get the maximum magnet strength in the gap w most fill.
He says all kinds of wrong stuff about magnets losing strength and related to heat. Even after like 4 minutes he’s said a bunch of incorrect things. And he’s talking to manufacturers and bashing some. I bet u could make a monster list of stuff he says wrong if u watched the whole thing. I’m interested in it and would tell u what I see as wrong that he says but with u not being on the phone and pausing it it’s too much
Hallbach is the beginning of the general idea - but it seems that Sandy Munroe’s teardown of the Tesla motor mentioned that Tesla went beyond Hallbach and corrected the things that weren’t working for the original Hallbach arrays - they developed their own version and secret sauce of the Hallbach array which (IMHO) probably meant that the magnets would never lose their strength or heat up as dramatically as a normal Hallbach would purport to do. If only we could find out what that was…
The motor itself is real beauty! battle hardened to the brim.
The magnets, hallbach or whatever configuration, heat up by heat coming off the stator or eddy currents. so if u have more segments it’s less eddies produced just like the stator laminates. Neodymium lose their strength only through time, a long time and equally in that way regardless. The only other way they lose their strength permanently is through if exposed to a strong enough opposite field or high enough heat or a combo. The temp rating is revealed in the letters after the number ex:N48sh which are good to I think was 300f before permanent loss of strength. Rarely see manufacturers post it and assume they’re low temp as they can be a big expense and most of the motors we use are for planes and have better cooling and generally they don’t get them that hot.
There’s the max operating temp of a magnet and also the Currie point at which it is permanently damaged. Between the two the magnet will lose some strength but it will return when it cools. When it loses strength the kv will go up so maybe u could figure what heat ability ur magnets can take and if your max speed is increasing when the motors are hot (maybe doing a load less test just lifting the deck off the road) u can get an idea of how close ur getting to the Currie point
Amazing how the car motor magnets are so thin and the field is being shaped and utilized so well
I don’t use that specific product, but the JB Weld Original Steel 8265-S actually has real steel in it – it’s not just a marketing name.
So I am not sure what adding extra steel around the magnets will do, but I suspect if it weakens the fields at all by allowing leaking from one magnet to another that it could possibly raise the Kv but you’d have to ask a motor expert what putting steel around the magnets would do.
I’m putting my test rig together now and will commence experimenting soon… kV is one aspect I wish to test, as is weight, structural integrity, ease, power (thrust) etc. anything else can you think of that I should test or sample before I commence?
I feel like kv and it’s inverse kt reveals most. The winding resistance will stay the same and if the kv goes down, kt is going up, and ur getting more torque for a given copper loss. The only variable being if the kv goes down but the iron losses are going up… You should be able to tell that doing a no-load test at same high rpm.
1 figure the kv before and after
2. Compare the current draw/wattage at a high erpm/rpm before and after. Less is better
Those two comparisons should really reveal everything related to performance of the motor I think.
As long as u don’t mess up the bearings or c-clip in each attempt should be an excellent comparison. Excited to hear how it goes
Maybe the glue u have could even take a bit more iron powder. Easy to find at the beach.
I’m putting my money on both being lower kv and possibly lower current draw at same erpm. No idea
But if it’s not balanced as well that would be a variable.
Kv I’m going to look at twice, looking at the calibrated spin test and voltage but also using VESC tool to calculate kV from eRPM…
I’ve got the test rig up and running on a FocBox running a 4s lipo (test subject is a 2306 2300 kV (listed) kwad motor.
I’m going to start by throwing 3amps at the motor and check heat and up the amperage till it starts to get above warm…
I was lucky to find two identical bells in my kwad box… one is bent and can only be used in static tests, and one is acceptable… however both contain at least one loose magnet, and the remaining magnets suspect… after I’m finished active testing I’m planning on destructively testing these battlehardened motors to submission and note the failures.
I’ve also got a few actual esk8 magnet chunks that I plan on hardening outside of a bell and inside of a bell and test these samples to destruction…
Thanks for your opinion and suggestion… I’ll try and statically balance the bells as much as possible on my k00k desk!
I was just thinking u could go off the vesc kv results but if u do it the other way spinning the motor n getting an output I guess u could if u have the tools
If u use the same motor n balance before checking the kv and no-load current at some high erpm and then glue, and balance, then the tests on the same vesc that seems easy and reliable
Balancing with the mounted laser seems good and easy.
