Endless Sphere

I'd say just use your original motor until it fries. Maybe try statorade to help cool it down between climbs. If you can open the motor up and install a temp sensor, that would also help you roll back the power if it starts overheating.

That looks pretty fun. A bit dangerous if there is actually a blade spinning under there and you are driving like that guy in the video... You need 4x reversing esc's capable of around 20A or more. One for each motor. It would be cheaper if you went with just two motors and 2x esc's. Two motors woul...

what i said in a broader sense to include more than transistors. It all goes back to supply voltage. The power you can get out of a load is given by its resistance (at DC) or its impedance (at AC.) At 32 ohms you can get 4.5 watts out of a 12 volt supply. At 4 ohms you can get 36 watts. So often ca...

If you don't understand how a badboy charger works, you shouldn't be using one. I'll give you both a hint - you don't.

Without anything to limit current, you will blow your fuse immediately. The peaks of the AC waveform will put 1000s of amps into your battery.

shaman wrote: ↑

Feb 11 2020 11:02pm

SRFirefox wrote: ↑

Feb 11 2020 6:52pm

You could dunk your motor in a tub of water to keep the heat down for the 50A test.

I don't know man. How do I know everything is waterproof up in that motor?

Check phase resistance and insulation resistance. Submerge motor. Repeat measurements.

markz wrote: ↑

Feb 06 2020 2:13am

so is it the browser or the phpBB forum that underlines, in red, with a squiggly line like in this post, phpBB

it's your browser, right click on the word with the squiggly line, and you will see your browser's spell checking options

https://www.electric-skateboard.builders/t/freewheel-spinning-on-a-mellow-drive/14497 Cogging torque is a "sine save function (repels and attracts equally)" - Mellow boards themselves Just picture a single magnet spinning past some stator teeth. When it is aligned with a tooth, forces are balanced. ...

You need to worry about the peak of the AC waveform, 110*sqrt(2)=156V, being under your battery voltage, so you need a bit more voltage step down than you think. I also doubt the controller will be very happy with pure rectified AC as its voltage source, so you will need to add some capacitance on t...

Motors need AC to spin. Even brushed motors take DC in, but they use their brushes and commutator to convert the DC into AC before it goes to the windings. Switching DC turns it into AC. Just because it's not 60Hz doesn't mean it's not AC. BLDC motors take an AC input of varying frequency and amplit...

Correction, my 20 amps max regen is just under a 4C rate. My Panasonic Sanyo GA cells have a charge constant of 1.675 amps. Thus a 3p battery configuration gives a 1C rate of just over 5 amps (5.025 to be exact). So 20 amp charge rate is 3.98C for my battery. To be clear, I am not a battery expert....

Thanks for the reply!! So this is interesting... I figured the kick/dogscooter would be much safer than the 8" ones, and I also figured it was about the same or possibly even a bit safer than a e-bike? Now, I have no idea if this is remotely true, so can you help me understand the technical reasons...

I still don’t understand how transitions, the magnet wire connecting wound teeth, transits, will have more losses if a high kv and fewest turns. As you show it with parallel strands with your graph if you added resistance of the wire it will decrease in proportion to the more strands in parallel. A...

...iron losses as proportional to the square of rpm... That part is a new one for me. I always thought iron losses increase in amostly linear. Below is a quick graph I did using Miles' Motor Comparison Spreadsheet with a HubMonster hubmotor as the motor, for which the input numbers I provided to Mi...

When people (including me) have said that peak efficiency is when copper and iron losses are matched, we are basing it on approximating iron losses as proportional to the square of rpm just as copper losses are proportional to the square of torque. This does ignore hysteresis losses which are direct...

For me, once you move above the convenient size and weight of the 8" scooters, you're probably best off just going to a normal bicycle with 26"+ wheels. I feel like the middle ground dogscooter is kind of the worst of both worlds - not very portable and not as safe as a normal bike. I guess the only...

I don’t agree, can prove it too :D https://endless-sphere.com/forums/viewtopic.php?f=30&t=102934#p1505953 In theory all is equal but in real life it has limitations. -Controller cannot be matched (within reason) to ALL possible kV and winding. It can get too big, too expensive or too complex to mat...

john61ct wrote: ↑

Jan 08 2020 1:15pm

....

john61ct, Kv is not going to help your example. We are talking about getting peak power out of motors disregarding heat generation. Changing Kv does not change heat generation for a given torque. I think you know that and were just hoping this thread debunked that. It does not.

power = torque * rpm torque is proportional to phase current rpm is proportional to bemf thus, power = phase current * bemf Maximum peak power output from a motor is reached at 50% of max speed, 50% of stall torque, 50% efficiency This power usually isn't sustainable or achievable for larger motors ...

.... Notice how we haven't and will not be able to exceed 1000W of output power from the motor and this peak is at 50% of the unloaded KV and is only 50% efficient. You might notice from the math that if we produce 19.9V BEMF out, the motor is producing 19.9W with 20W input which is 99.5% efficient...

.... The only difference is that i use 11t sprocket instead of 10t, but i remember using the same on D5035 and it wasnt even close. I tested it sensorless and with the same phase current of 30A. I would say that in this unfair configuration it's a little bit behind D5035 but very close in terms of ...

Not sure how much money you have, but LMX has a solution.

https://lmxbikes.com/en/spare-parts/94- ... r-hub.html

New toy time: .... This puppy with chinese pedigree is very close in size to the orange D5035 but it's much heavier(~+250g) and at half the price! I wonder if it's more copper in there.. I didn't test it yet cuz i had a hell of a time enlarging the 8mm ID of 11t sprocket to 10mm as this motor's sha...

.... I'm still doing searches on the 1.41T thing, it's difficult to find the right search title. But what I see so far is that indeed, a typical core does approach 1.41T, when the tooth face is closer to 1T. magnetic-flux-density-at-rest-simulation.png Lots to look at yet. Lebowski said 141%T not 1...

flat tire wrote: ↑

Jul 29 2019 1:57pm

APL wrote: ↑

Jul 12 2019 1:49pm

free energy shit

What the hell? The guy that built this beautiful looking motor is one of these people? No wonder he can't get it to work.

Note he said wind to heat generation, so I'm pretty sure he realizes that the energy isn't free free.

galp wrote: ↑

Jul 29 2019 10:03am

Part you listed is obsolete.

The datasheet says obsolete, but it seems to be readily available and active from digikey and mouser, so it's probably fine to use for new designs. With HighHopes and zombiess recommending the chip, I'd say it comes with some pretty strong credentials.