That is why some people played with thinner/thicker wires or higher/lower voltage etc. Btw, bigger cable has more space/pipesize to store the balls, thus can have more volts to reach its “dense enough” capacity. Thats why they dont run 100 amps at 1 volts nor 1 amp at 100 volts but at 5 amps at 15 volts assuming that it’s efficiency point are at 15 volts per given capacity. (It’s just an example).
Can we use N52 or 50M to get more torque on the permanent magnets side?
Here is a magnet chart https://www.amazingmagnets.com/magnetgrades.aspx
stronger magnets will drop the kv with everything else being equal so to bring it back to the same kv you can use less turns of wire around the tooth, so therefore thicker wire with less resistance, better. but scorpion motors as an example use low strength magnets with very high heat ability and they have great claims of improved wattage produced. I wonder how this would go really and utilizing high heat magnets and then being able to have a higher continuous operating temp before the magnets suffer requires having the resistance of the copper go up forty percent from 20c to 120c. On a small motor, hub motor, copper losses are the biggest lose. if you want to strike the perfect size motor for the job, no size or weight considerations involved, you eventually have enough copper so that the iron losses will equal or surpass. So copper losses are everything in a hub motor…except…except…the dreaded magnetic saturation of the stator as it’s small and forced to produce huge magnetism. as it saturates it suffers greater hysterisis, meaning the polarity is slower to flip back and forth as is wanted. How much copper losses vs iron losses are in a small wheel hub motor I don t know
I dont know what youre saying exactly eblade and there’s lots of different situations but inside the motor alone you can get the same performance, meaning same torque to heat ratio, regardless of what voltage is plugged to the esc. so i read.
to explain it In my own words I’d say you plug it in and then that’s when the magic happens.
theres a lot in that thread i posted and i cant find the exact words i’d like to pull out. i’m just leaving it here till someone comes and tells it better.
Please stop hijacking this thread about this matter. It’s really annoying.
Sorry @brams for posting again. I will open a new thread trying to explain why hub motors produce more heat than satellite motors, so no more hijacking from my side.
@devin and @Hummie, is a motor like a power line? Yes and no. Fact is that the same motor sometimes acts like high voltage / low current power line, sometimes like a low voltage / high current power line.
And this is not dependent on the thickness of the wire inside the motor.
@Hummie Is a thicker magnet than another with the same grade like N50M is more powerful and then will permet more thicker copper? Like if I double thickness of actual magnets
add stronger magnets lowers kv so you can then use thicker wire to get it back to the higher kv. details of how much of this equals that I dont know. or add a thicker back iron/flux ring. or hallbach array
I’m gonna hit the pause button right here.
Thread Subjects:
- Smaller Hub Motor Designs and Complications
- Heat and Wattage (as it pertains to motor design)
- Magnets and Rotors (as it pertains to motor design)
Thread Summary: Smaller Hub Motors need to be designed to compensate for heat and efficiency problems. Either longer stator for increased torque or windings need to change to reduce current flow for less heat.
A wire has resistance. Passing current through it incurs a force similar to friction, thus generating heat. By increasing the current while maintaining wire resistance will increase heat. By decreasing the current while maintaining the wire resistance will decrease the heat. The relationship of Watts to volts and amps is key here (but also not everything as theory and reality in design rarely are the same). You can have two designs where the wattage applied is the same. Theory would suggest that the magnetic field would be operate under reasonably similar conditions to similar results. Theory would also suggest that a motor designed with a stronger volt:amp ratio under no load would operate more cooly as the lower current would encounter less resistance thereby reducing heat. Logistically, we have to consider motor load which will cause heat to build up in both designs. Based on theory, we should expect less heat from a system running at a higher voltage with a capped current (to match a motor with similarly capped wattage) which also decreased wasted watts.
My personal opinion is that Hummie’s motors are constantly at the limits of their design - his thermally tolerant magnets and wires will give you the performance but are be losing precious watts to heat. This is neither optimal or practical for endurance runs where heat buildup is inadvisable (aka 100*F weather).
Before anything is further said on this subject, we need practical evidence and data. I would like @Hummie to hand wire two stators for his motors (for equivalent copper content but with different gauges). Moving his own weight using only one powered wheel test the practical performance of ONE motor under load. Configure the VESC for this motor which we will cap at 1000watts. One system at 6s and the other with 12s both capped amperage for 1000W. As described above, theoretically the high voltage (12s) system should be cooler when consuming the same amperage when compared to the high current (6s) system. Please report these findings to the appropriate thread (and link results to this thread too).
Finally, Magnets. Flux ring and magnets are important. At a certain point, increasing magnetic fields with stators this size will decrease top speed and increase torque. Practically it will only increase expense (not by much, btw). In a hub motor, this might be desired but remains to be tested (see above).
I can’t spell his name but someone here has done this test and posted the results here. Abit worse efficiency running on 6s instead of 12s. Running at 12s, if ur going the same speed as 6s, u are forced to be at further from the no-load speed and therefore a bit more inefficient. He measured amp or watt hours.
Voltage won’t make the motor cooler but increasing the flux in the gap with stronger magnets, smaller airgap, and bigger stator, will allow you to use a thicker wire with less resistance as less turns on the tooth are needed to get required flux.
I do 90kv and if I did 50kv I’m sure they would run cooler but who wants to go 18mph.
You can design a moto to run a motor efficiently and it will have a high max continuous power and if I did 50kv itd be more efficient but who wants to go 18mph? it may be more electrically more inefficient but mechanically more efficient. The difference in watt hours expended I don’t know at different speeds and I hope to test and compare with ginra and his gt
I want ! 
Since it’s actually a 22" board, I would like to go between 15mph and 18mph, as it would wobble at higher speed. I have a 6S battery at 40A continuous made of 18650. The max power W that I can get with these constants PER motor in a dual drive setup is Power = Amps * Volts / 2 = 40 * 3.7 * 6 / 2 = 444W.
With 400W dual drive motors stuffed into 59mm wheels, will it be that much heat? Active cooling with forced air could also be considered.
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the forced-air cooling designs i had done, three of them, did little. Not that it necessarily not be that effective just what I made had minimal sized blades and I’ve heard of forced-air cooling being effective for hub motors when done right.
You can have more amps put to the motor than come form the battery. the sidetrack above is about that. I dont know much but know on the vesc theres a max amp limit from the battery, and a max amp limit going to the motor. they are not the same and depending on your speed I believe the voltage is converted to amps in the motor. …infact maybe it’s the only way to make an amps x volts equals watts equation work because a motor, which is an inductor, only responds to amps not watts, inductance formula is a combo of turns of wire times amps. I’ve been on the hunt for what volts do in a motor for a long time. PB1 is hopefully going to give an understandable breakdown of the magic.
59mm wheel? what’s the motor size?
Ill get off my ass today, away from the polyurethane fumes, and get the wattmeter out and finally do some wattage to heat outputs. 18mph for me on the 4725 stator I’m riding I could do all day I’m sure. I do also have good stuff in the motor but then again there isn’t nearly as much copper in the 90kv I have as could be and that’s important and the magnets are only n45sh and not n48s as I’ll do in the future…
((the temp ability of the magnets and therefore the max temp the motor can get to seems to increase the max continuous wattage producible . how that plays out I’d like to know exactly as well)) I’ll find what wattage it is at those speeds and the temps. kmeyerson that’s a tall order, maybe you’d like to rewind the two I shorted. it’s an awkward rewind with the steel wall close by. I want to say namasaki is his name…or haimindo, he did a test without the rewind to match the voltage so ran 6s on the same motors and get better efficiency…a little because of being further from the now load while on 12s. not the test as you want. it’s been done though.
Yes of course it’s possible to put more amps into a motor than amps are coming from the battery. What needs to stay the same is the power P=U*I,
Let’s say on the battery side we have 37V*20A=740W
Now the voltage on the VESC output side is also 37V, but only in very short bursts, so we have to think average voltage. Average voltage will be lower depending on how fast the motor turns. Let’s say its 20V. Then 740W / 20V = 37A will flow through the motor producing torque and a power of 740W. All simplified because I’m negeglecting losses here. In real life it would be even more amps due to losses.
Yes @hummie, I’ve started writing an article about all of this. I’ve finished the stuff about the workings of a BLDC motor, now I’m concentrating on the figures and hub motors. It will be a while.
Now let’s hand over this thread to the OP.
Oh, and @devin, you can’t transform DC, you can only transform AC.
That’s CONVERT and not TRANSFORM!!!
You can convert DC. Never said anything against that.
But you can only transform AC.
While the end result might be similar, the technique of converting and transforming is very very very different!!!
that is what he meant and you knew it all along. If he did not use the scientifically correct terminology you could have pointed that out nicely.
Yes, fully agreeing with you. I knew what he meant.
I mentioned it because:
- I wanted to be a smartass
- when talking about all of this stuff here we need to be precise. So when I see a mistake like that => see 1)
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instead of going to 1) you should have gone to 3) tell the correct way and teach your fellow eboarders
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