Search found 742 matches

by major
Apr 14, 2018 7:38 pm
Forum: Motor Technology
Topic: Advanced DC K91-4003 max voltage
Replies: 5
Views: 94

Re: Advanced DC K91-4003 max voltage

For the open revolt look for Sabrina Holmes on Evtech discussion list, http://lists.nnytech.net/listinfo/evtech Also occasional poster on diyelectriccar forum. Taking more of a risk with eBay IMO. I think tech support has been there for open revolt builders. You'll like 500A way more than 300. Good ...
by major
Apr 13, 2018 10:25 pm
Forum: Motor Technology
Topic: Advanced DC K91-4003 max voltage
Replies: 5
Views: 94

Re: Advanced DC K91-4003 max voltage

I doubt that the voltage you state will be a problem. Your controller will limit the voltage to the motor. So what you need to do is figure a way to observe the brush/commutator area as you accelerate, keeping the RPM within limits. If it starts arcing badly then you'll need to advance the brush pos...
by major
Mar 25, 2018 11:36 am
Forum: Motor Technology
Topic: End turns bad?
Replies: 246
Views: 5454

Re: End turns bad?

Anyone thought of totally reshaping the core to better contain the flux coming off the (end turn) windings like by using something other than laminations of M12 steel like with powdered metal tech which can also reduce Eddy currents in the core? Hi Jan, Sure, lots of folks look into it. One example...
by major
Mar 24, 2018 11:12 am
Forum: Motor Technology
Topic: End turns bad?
Replies: 246
Views: 5454

Re: End turns bad?

Ampere's Law applies, universally. That depends upon whether you are taking Maxwell's correction into account; which you obviously aren't. So you stopped being correct in 1861. And why do you think your motor has displacement current which needs attention to calculate the torque and voltage? Yes. R...
by major
Mar 24, 2018 9:12 am
Forum: Motor Technology
Topic: End turns bad?
Replies: 246
Views: 5454

Re: End turns bad?

Buk___ wrote:
Mar 23, 2018 11:38 am
This is where we differ. I see coils wrapped around core, you see them "passing thru". Its a subtle distinction, but one which makes a (IMO) significant difference.
Bingo! And you are wrong.

Just like Ohm's Law, Ampere's Law applies, universally.

Thanks,

major
by major
Mar 23, 2018 2:04 pm
Forum: Motor Technology
Topic: End turns bad?
Replies: 246
Views: 5454

Re: End turns bad?

Firstly, let me apologise for not getting back to you earlier. I had part written a reply, when a distance memory of something I had read stirred in my brain. It took me a while to to remember where and what, re-read it -- this time trying to understand it -- and then I had to run a bunch of simula...
by major
Mar 22, 2018 1:08 pm
Forum: Motor Technology
Topic: End turns bad?
Replies: 246
Views: 5454

Re: End turns bad?

To help me understand you, could you post a modified version of that image showing where the motor's axle would run? In the mean time, go back to the original posted diagram of this core. The green line in the air gap would be on a radius from the axis of rotation relating this to a motor, if that ...
by major
Mar 22, 2018 9:59 am
Forum: Motor Technology
Topic: End turns bad?
Replies: 246
Views: 5454

Re: End turns bad?

... perhaps repeat sim 1 or 2 with those 4 conductors moved far away from the core to see that it doesn't alter the air gap flux. I'm more than happy to modify the sim(s), but I suspect we are again (still!) talking at cross purposes, in as much as I think you are envisioning a quite different scen...
by major
Mar 22, 2018 8:07 am
Forum: Motor Technology
Topic: End turns bad?
Replies: 246
Views: 5454

Re: End turns bad?

That's very interesting. I don't see where the location of the coil affects the flux map. And how any of that shows any contribution from conductors not passing thru the core. I suspect you're using too low of a current against the magnet strength. Maybe try 200A or more. Trying to stay focused on e...
by major
Mar 21, 2018 9:05 pm
Forum: Motor Technology
Topic: End turns bad?
Replies: 246
Views: 5454

Re: End turns bad?

Below there is flux map of a magnetic circuit with an air gap on the right (green line) and a 4 turn coil on the left providing excitation (mmf). Due to the cross sectional view, the coil shows as 8 black dots which represent conductors perpendicular to the viewing screen. There are 4 conductors pas...
by major
Mar 21, 2018 12:45 pm
Forum: Motor Technology
Topic: End turns bad?
Replies: 246
Views: 5454

Re: End turns bad?

... BTW, I used the term "core" when addressing Ampere's Law because of the motor context. It is actually the magnetic path. So in your solenoid examples the magnetic path completely surrounds the coil, therefore there are no end turns. In the motor FEMM you see only a cross section. Only leakage f...
by major
Mar 18, 2018 5:18 pm
Forum: Motor Technology
Topic: End turns bad?
Replies: 246
Views: 5454

Re: End turns bad?

Fix = secure? https://endless-sphere.com/forums/download/file.php?id=229871 Electronially commutate, secure the coil and allow the magnets to rotate. Isn't it a 2-pole bldc? What you would have is an ironless, air-coil motor. ... ... And due to the nature of the simple diagram, realize that the arm...
by major
Mar 18, 2018 2:59 pm
Forum: Motor Technology
Topic: End turns bad?
Replies: 246
Views: 5454

Re: End turns bad?

Fix = secure?

Image

Electronially commutate, secure the coil and allow the magnets to rotate. Isn't it a 2-pole bldc?
by major
Mar 18, 2018 2:51 pm
Forum: Motor Technology
Topic: End turns bad?
Replies: 246
Views: 5454

Re: End turns bad?

No. ... >snip< Fix the coils and allow the magnets to rotate and then yuo have an outrunner BLDC. First no. ... Then yes. ???? Why isn't that subject diagram a 2-pole BLDC? It's all in the >snip<. You start with flour; add yeast and water and salt; kneed, prove, bake; you get bread. If you snip the...
by major
Mar 18, 2018 12:50 pm
Forum: Motor Technology
Topic: End turns bad?
Replies: 246
Views: 5454

Re: End turns bad?

Buk___ wrote:
Mar 18, 2018 12:38 pm
major wrote:
Mar 18, 2018 11:39 am
if the coil was stationary makes the example a bldc, doesn't it?

major
No.
... >snip<
Fix the coils and allow the magnets to rotate and then yuo have an outrunner BLDC.
First no. ... Then yes. ????

Why isn't that subject diagram a 2-pole BLDC?
by major
Mar 18, 2018 11:39 am
Forum: Motor Technology
Topic: End turns bad?
Replies: 246
Views: 5454

Re: End turns bad?

... But they all have 3 significant difference from BLDCs: The Lorentz force generating coils are in the rotor not the stator. The two sides of each turn of coil are on opposite sides of the axis of rotation, not the same side. The stator field, whether from PMs or generated by stator coils, is uni...
by major
Mar 15, 2018 4:34 pm
Forum: Motor Technology
Topic: End turns bad?
Replies: 246
Views: 5454

Re: End turns bad?

Buk, EndLoopsFEA.jpg EndLoopsFEA (1).jpg Is this a cross section of a single tooth, the plane of which is perpendicular to the radius of the motor? Yes. It might (for example) be a slice taken as shown in red in this inrunner model: 18t16pZoom.jpg 18t16pZoom.jpg , but could equally well be an outru...
by major
Mar 15, 2018 8:48 am
Forum: Motor Technology
Topic: End turns bad?
Replies: 246
Views: 5454

Re: End turns bad?

Buk,
EndLoopsFEA.jpg
EndLoopsFEA.jpg (93.34 KiB) Viewed 418 times
Is this a cross section of a single tooth, the plane of which is perpendicular to the radius of the motor?

It also appears some of the field lines cross other field lines. Please comment how that happens.

Thanks,

major
by major
Mar 13, 2018 10:47 am
Forum: Motor Technology
Topic: End turns bad?
Replies: 246
Views: 5454

Re: End turns bad?

Buk, I posted this a week ago. It just doesn't sink in. Another clue is Ampere's Law. The contributing current to the magnetic flux in a core is that which passes through the core. Current passing around the outside of the core does not contribute magnetically but only serves to deliver current to t...
by major
Mar 13, 2018 7:40 am
Forum: Motor Technology
Topic: End turns bad?
Replies: 246
Views: 5454

Re: End turns bad?

So the Lenz law will indeed contribute to torque of a stalled motor,  But ... Lenz Law induced current and the field it creates, opposes the current that originated it and the field it creates, so rather than "contribute to the torque of the stalled motor", it would have to detract from it. It coul...
by major
Mar 12, 2018 8:11 am
Forum: Motor Technology
Topic: End turns bad?
Replies: 246
Views: 5454

Re: End turns bad?

Buk___ wrote:
Mar 12, 2018 12:28 am
... Lenz Law require the magnets to be moving; ...
I don't think so. The law addresses a changing current in a conductor or coil. When viewing web explanations or textbooks, often an illustrated example is seen using a moving magnet, but the law does not require a moving magnet.

major
by major
Mar 11, 2018 10:07 pm
Forum: Motor Technology
Topic: End turns bad?
Replies: 246
Views: 5454

Re: End turns bad?

... The motors we use have much more complex topology, and far more complex and contained magnetic circuits. Something like this (simulated on a similar 100mm diameter scale to the wire loop motor simulation above): 4pole3toothMotorMagbeticCircuits.jpg 4pole3toothMotorMagbeticCircuits.jpg Perhaps y...
by major
Mar 11, 2018 11:46 am
Forum: Motor Technology
Topic: End turns bad?
Replies: 246
Views: 5454

Re: End turns bad?

Newton's Third Law? ... I'm having trouble applying newton to that? ... Lenz Law? Chicken and egg I think. The magnet has to move first, so if it was responsible, there's be no torque from stationary. For Lenz Law, the magnet moves first, the current induced creates a field that opposes the magnets...
by major
Mar 11, 2018 7:34 am
Forum: Motor Technology
Topic: End turns bad?
Replies: 246
Views: 5454

Re: End turns bad?

Buk___ wrote:
Mar 11, 2018 4:56 am
major wrote:
Mar 10, 2018 2:25 pm
Buk___ wrote:
Mar 10, 2018 12:13 pm

Does it say how Lorentz forces acting on the coils in the stator of a BLDC motor, could impart any torque at all to the rotor?
Newton's Third Law?
...
I'm having trouble applying newton to that?
...
Lenz Law?
by major
Mar 10, 2018 2:25 pm
Forum: Motor Technology
Topic: End turns bad?
Replies: 246
Views: 5454

Re: End turns bad?

Buk___ wrote:
Mar 10, 2018 12:13 pm

Does it say how Lorentz forces acting on the coils in the stator of a BLDC motor, could impart any torque at all to the rotor?
Newton's Third Law?