Magnet dimensions - RC-Monster Forums

Dafni · **Magnet dimensions -** 12.20.2005, 10:33 AM

Boys, I was thinking about the dimensions of our magnets, and then it hit me: The Lehner numbers must be the diameter and lenght of the magnet!
For example: 1940 - 19mm diameter, 40mm lenght.

Sounds reasonable, doesen't it?

I know for a fact that the Feigao (or Wanderer) L-motors have 19x30mm magnets. So the XL will have a 50mm long magnet? Just guessing.

I thought I should share this interesting train of thought, but maybe you guys knew about this.

DAF

Papa · 12.20.2005, 10:40 AM

So following that theory a 2240 would be 22x40. Sounds plausible.

Dafni · 11:41 AM

Exactly. Which equals to 15,2 cubic cm of magnet for the 2240, and 14,18 cubic cm for a 1950. (hole for shaft neglected)

Batfish · **Re: Magnet dimensions -** 12.20.2005, 11:42 AM

Quote:

Originally posted by Dafni
Boys, I was thinking about the dimensions of our magnets, and then it hit me: The Lehner numbers must be the diameter and lenght of the magnet!
For example: 1940 - 19mm diameter, 40mm lenght.

Sounds reasonable, doesen't it?

I know for a fact that the Feigao (or Wanderer) L-motors have 19x30mm magnets. So the XL will have a 50mm long magnet? Just guessing.

I thought I should share this interesting train of thought, but maybe you guys knew about this.

DAF

I've often wondered what a good example would be to demonstrate the differences between the really technical folks and us not-so-technical folks. The fact that you start your post with "I was thinking about the dimensions of our magnets..." is exactly the example I have been looking for :)
This is why you guys recommend systems and I just race them :)

Nick · 12.20.2005, 12:19 PM

7XL = ? :D

Yeh it makes sense with the number model, I guess the 7XL goes by another number?

squeeforever · 12.20.2005, 01:20 PM

7 is for the number of winds or turns isnt it?

SpEEdyBL · 12.20.2005, 02:38 PM

Feigao 540 Rotor Lengths:

S: 21 mm
L: 30 mm
XL: 45 mm

I think they're all 19 mm in diameter.

Gustav · 12.20.2005, 02:49 PM

A lehner 1950 is the same length as a feigao XL though(externally),so on that basis wouldn't it be a lehner 1945?Maybe it does have a 5mm longer rotor though.Anyone feel like opening up their 1950 to find out?

Serum · 12.20.2005, 04:17 PM

Coool thinking Daniel!!!!

really cool!!

Dafni · **Re: Re: Magnet dimensions -** 12.20.2005, 07:06 PM

Quote:

Originally posted by Batfish
I've often wondered what a good example would be to demonstrate the differences between the really technical folks and us not-so-technical folks. The fact that you start your post with "I was thinking about the dimensions of our magnets..." is exactly the example I have been looking for :)
This is why you guys recommend systems and I just race them :)

LOL yeah, scientist at heart. Always wonderin' about the How and Why, and how to improve things. Can't be helped, and can't be stopped either, the brain just rattles on and on.

Maybe I should tell you why I was thinking about that. Well, those Lehner guys sell their nice magnets as spare parts....the rest of the story is obvious.

Cheers
DAF

Gustav · 12.20.2005, 07:11 PM

Not that obvious to me.You were going to try a 1930 rotor in a 9L or something?Could be a cunning plan maybe.

Dafni · 12.20.2005, 07:20 PM

Quote:

Originally posted by Gustav
A lehner 1950 is the same length as a feigao XL though(externally),so on that basis wouldn't it be a lehner 1945?Maybe it does have a 5mm longer rotor though.Anyone feel like opening up their 1950 to find out?

That's another reason why those Lehners have better efficiency: Longer magnets in comparison to the copper strand layer. The copper "behind" the magnet does nothing for power, it's just electric loss.
I'm almost sure the 1950 has a 50mm magnet, and the Feigao XL have 45mm.

Quote:

Originally posted by Gustav
Not that obvious to me.You were going to try a 1930 rotor in a 9L or something?Could be a cunning plan maybe.

Yeah, exactly. The Lehner magnets alone are rather cheap. And the 1950 already has a 5mm shaft, too.

Serum · 12.20.2005, 07:22 PM

perhaps i should get a 1950 too.. Instead of an 11xl... Come to think of it..

Gustav · 12.20.2005, 07:28 PM

Sounds like a very cunning plan then!How much is a replacement magnet?

So ageing 'L' motors could become a poormans 1930s and 'XL' become 1950s.Marvellous!

coolhandcountry · 12.20.2005, 07:59 PM

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.