Magnet dimensions

[Gustav]

Worth an experiment though.It wouldn't make it a Lehner no,but if it fits then the segmented magnets might be an improvement.Only one way to find out i suppose.

Maybe the copper strand behind the magnet isn't all loss but presumably less efficient than that around the magnet(i don't really know).It all adds up.

[coolhandcountry]

I took a lehner 1930 10t apart. I also had a feigao 8l I took apart. here is some difference. The windings in a lehner are a lot closer than the feigaos are.

[Gustav]

Very interesting indeed.What's that on the ends of the 8l magnet?
Do you think the lehner rotor could fit with some spacers made?
Rear bearing inner diameter looks different too.

[coolhandcountry]

the lehner 1930 has 4mm shafts. They are like rings on the end. I don't know if it would be enough gain to talk about or any at all.

[Dafni]

Originally posted by coolhandcountry
I don't think making a lehner out of a feigao is going to be that easy as to just change the rotor(armature). The copper strands help make up the magnetic field to push the magnetized rotor. So I kind of disagree on they are just electircal lose.

Of course. I just meant the part of copper strands that are not at the magnet. The part where all the winds are knitted together, on the rear of the motor.

Nice pic, Leeroy. Thank you. I'm kinda dissapointed that those segments are this fat! Somebody told me the segmenting would be most efficient if the segments are 0.2mm thick. (almost zero eddy currents)

[Serum]

Wasn't that me Daniel?

that is the same experience i have with transformers.

I saw that pic, and thought the same thing, about the thickness of those layers.

[Dafni]

Possibly, Rene. Let's see what the BK boys bring on.
At least Lehners 2.5mm segments are better than the big Feigoa blocks.

Also, the outer Can, the actual motor housing, is fine layered. And I noticed the Lehners seem to have thinner layers than the feigaos. (just for clarity, I'm speaking of the stuff that's purple on Feigaos and black on Lehners.... the motor housing is kinda like a stack of rings, if you know what I mean)

[SpEEdyBL]

Originally posted by Dafni
I'm kinda dissapointed that those segments are this fat! Somebody told me the segmenting would be most efficient if the segments are 0.2mm thick. (almost zero eddy currents)

I saw a pic of a plettenberg rotor and it had much thinner segments than the lehner.

[Dafni]

Here's another one: On the HiAmp versions of the Lehners the windings are visible. The wires ar the back are the actual windings, just like with Feigaos. Now, the higher turns have much thinner windings (the bundle is thinnner) than the lower turns. Why is that?? And has this an influence to the torque?

Thank you
DAF

[Serum]

Reason for that is because they need to route longer wire in the higher winds than in the lower winds Daniel, it simple is thinner and longer. Get it?

A higher KV has got a higher resistance because of this.

[Dafni]

Thank you rene, we might talk about this some more later on.

Here's some news I learned in regard to those segments: Altough thinner segments would gain efficiency, they would rob torque. So the Lehner design must be some kind of ballance then.

Just thought I should share this with you.

[GriffinRU]

I think you referring to different type of motor...
The only advantage of making rotor from sections is to get stronger magnetic field (in comparison with single one) and make it more uniform in production and probably uniformity of the magnetic field as well. To obtain higher torque you need to create more poles or add core but by doing that you sacrifice speed in first case and efficiency in the second one. Different wiring schemes are focused on reducing motor inductance and resistance, as well as heat dissipation (air is bad heat conductor, so special epoxies and winding pressing helps).
Also you can destroy magnets by applying high currents (especially when it is cold... well, different story) but in this case segmented magnet will be more tolerant to that situation.

Slots are great for stepper motors not for servo...

Artur

[captain harlock]

The kontronik motors uses big ( very big, actually.) segments in their rotors. There's only three segments in the rotor shown at their website, but probably its because the rotor is actually a 380-400 size. Probably the larger ones uses more segments, but I have to open up my FUN500-27 can and see for myself with eyes unclouded. The rotor is also nickle plated and it seems that the 19 series' rotor is also nickle plated to resist rust and humid. If the 500-27 rotor has only three segments, then I'll give up on the kontroniks and go for a 1940 instead, but then again, I'll pay 150 dollars extra for the 1940.

[Serum]

@griffinru;

The reason why to use segmente magnets, is because the eddy currents are much smaller, especially under partitial load. A segmented magnet hasn't neccesary got a higher magnetic strength than a non segmented.

To obtain higher torque you need to create more poles

not entirely; the power/diameter of the magnet is very relevant with this. And it is not said that a segmented magnet is stronger either. A big lehner motor (like the 2240/2250) will have loads of torque and at the right voltage it's also very efficient.

a 2 pole isn't weaker in torque than a 4 pole. (comparing a feigao XL with a plettenberg bigmaxximum)

A neodym magnet will loose his power above a certain temperature. (Daniel knows the exact number, i don't)

All the producers of BL motors use the pressed winding.

[SpEEdyBL]

A 4 pole will definately have more kt than a 2 pole of the same wind. That's why the plettenberg shadow is a 1 turn.