Endless Sphere

.... 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Part you listed is obsolete.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.

It seems that wiring the motor to a star connection should eat less current at an increased voltage. Which results in less electrical losses and an increased efficiency. The FETs on the VESC will be more happier too. Read around. Changing Kv by winding or star/delta changes does not change torque c...

FZBob, I really like this very simple and clean design. I have been following closely and am thinking about making my own. I also wanted to offer some technical equations for torque and phase amps that could maybe inform some of your motor, current limit, and battery choices. The key parameters to k...

On the first page you mentioned a theoretical max of 60Nm at the crank. Is that still the case?

Looks like a very clean lightweight kit! Very impressive! Can I get a quick test ride next weekend?

The 12V rating for that contactor is for the coil. It looks like the contactor itself is rated for 900VDC which should be plenty for your 400VDC battery.

So I take it looking at your renders there are no bus bars in this design, you'll be using direct connection at each FET set to positive and ground? Yes this is the case. Also the legs of the FETs will be bent to where each cable comes in to the board to help make a solid connection. This eliminate...

Simple models suggest that a motor is most efficient when its copper losses and iron losses are equal. Roughly, copper losses are proportional to square of current while iron losses are proportional to square of speed. I'm not exactly sure how your hydraulic load cell works, but perhaps you are runn...

I think it's an interesting idea. Are you trying to increase heat conduction from the windings to the inner core of the stator or to the end caps of the motor? Fwiw, I don't think zinc cast inside the stator core where the windings are will significantly hurt eddy or hysteresis losses. As has been p...

only bikes operated by the following systems may race: Bosch, Brose, Shimano, or Yamaha

Can you go into more detail or show some more pictures of your bottom bracket and mounting plate setup? I had the same idea of mounting a motor in front of the bottom bracket and driving the rear wheel directly on the left side. Specifically, it looks like you are running an ISIS bottom bracket? Is ...

Beautiful picture. The Tetons are one of my favorite national parks.

Would using a 60kV motor such as this one: https://alienpowersystem.com/shop/brushless-motors/aps-5065-outrunner-brushless-motor-60kv-1800w/ potentially open up higher voltages or simpler reductions? Nope, changing Kv does nothing to change a motor's torque capability, it only changes the voltage/c...

Markz, ProxRB is not messing up the turn count thing. He's just recognizing that spinning faster and gearing down to the same speed results in more torque capability. ProxRB, you don't necessarily need to increase Kv to increase speed. You could also increase your battery voltage. Besides being able...

First, I'll define my variables just for clarity's sake. Kv: rpm/volt Kt: torque/amp Rm: motor phase resistance P: power I: current V: voltage w: angular velocity T: torque Yes Kv is proportional to the inverse of turns. A 200Kv, 4 turn motor will be 100Kv if wound with 8 turns. Rm is proportional t...

larsb wrote: ↑

Aug 07 2018 3:44pm

This paper explained a lot to me on the harmonic losses, when they occur and some of the compromises in motor design:
Slot pole Combinations Choice for Concentrated Multiphase Machines.pdf

Very good read. Thanks for posting that!

Lol I spent like four hours reading and writing this post, so hopefully we can get this useful conversation moved to its own topic. I have read all the posts and links in this thread, and I think we all agree on a lot of things and disagree on just one thing. Agreements Different motors have differe...

My comments and conclusions from this article: "Reducing PM Eddy Current Rotor Losses by Partial Magnet and Rotor Yoke Segmentation" Regarding magnet segmentation right up front this article says this which basically maens magnet segmentation is not ever going to be something any manufacturer will ...

"..It's actually increased stator hysteresis losses not stator eddy losses from higher electrical frequency." @thepronghorn:As the frequency is one of the factors in below formula i doubt that you are correct. (It's from Wikipedia). Eddy current losses are proportional to the square of the frequenc...

... Of course that means you have a motor with 200 poles to eliminate the eddy currents. Clearly there has to be a middle ground between ridiculous magnet counts and minimizing eddy losses. I think this may be the reason why hubs and outrunners have lots of magnets. This may be the place where eddy...

I = 0.5*M*R^2 Inertia is directly proportional to mass but proportional to the square of radius, so moving mass closer to the pivot point will decrease inertia a lot. Your example of replacing a 4kg hub motor with 2kg of motor at let's say 1/2 the radius results in (1/2 the mass)*(1/2 the radius)^2 ...

Yes definitely get the Castle Link. The CC ESC needs some settings adjusted out of the box.

Drive unit weight: 7.5lbs Dimensions: 100mm diameter, 120mm length Engine: Neutronics 3215, 225kV Controller: Castle Talon 120, custom mount/heatsink, QS-8 main battery connect Performance (calculated w/ 120A phase): 135ft-lbs crankset torque 400RPM crankset 48t cog: 216ft-lbs wheel torque, 21mph 4...

Price?