Endless Sphere

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?

I'd say they still sell 1000+ tool packs for every Tesla that gets sold. Most of the tool packs aren't sold to average consumers for occasional use, they're sold to trades people that burn through these packs at a rate of several per year. Not sure about that... 2000 Model S and X last week = 16 mi...

Generally it's easiest to measure the width of 10 or 20 lams. The specs we need to characterize the performance of a motor are phase resistance, speed constant (aka Kv, rpm/volt is a common unit), and losses at no load at two different voltages. The page below discusses how to measure them all. http...

Like madin88 said, measure the Rm, Kv, and no load losses at two different voltages, and then we will be able to compare these two motors performance wise (inductance would be nice as well for an indicator of the "controllability" of the motor). You have already covered their mechanical design fairl...

Wow. This is amazing.

Did anyone else spot the super soaker water squirt gun strapped to the trike? What's it for?

Many 36V controllers will not appreciate being fed 84V from a full 72V pack. 63V rated capacitors are pretty common in them. Do some research first. .... I think you're talking to me here? That's why I said to use a 72V controller. If you're talking about my last sentence, I guess I should clarify ...