ES DIY Motor Challenge

enoob said:
... wich if im correct may actually work i just havent spent enough time working all the possible connection combinations.

If you like, give me the number of slots and magnets and I work something out for you. My goal was always to have a motorwinding with a low I0 and low cogging. They didn't reach the highest possible power/weight ratio but had a broad band of useful RPM.

-Olaf
 
welll. now theres an offer i wont refuse. even have enough parts laying round to send a copy (should we get is working) in lue of time spent on this with me.

thank you very much .

18 magnets . 42 slots.

the magnet count can be changed very easily the slot count would be a tad more time consuming but im willing to takle either one.

at this point i had intended to try a few combos i suspect may work and then commit to a rewind as that seems the best . to reduce magnet count ill have to increase the spacing between each .

the thread on how that little motor came around took a few turns but here it is . http://endless-sphere.com/forums/viewtopic.php?f=30&t=14264
 
YUK!
42 slots mean 14 slots/phase. That doesn't leave much room for phantasy. You can either divide 14/2 or 14/7 or don't divide at all.
Following the non_divide route I found a minimum of 28 magnets ( 14 pairs ) as a useful combination. Winding scheme is A1B1C1...A14B14C14
That would also work with 7*2 tooth, scheme is then A1a1B1b1C1c1...A7a7B7b7C7c7
I hope you are familiar with this description?
The magnet diameter shouldn't be bigger than the head of the tooth.
You're not planning to build a hallbach array this time? Or did you think of 18 mag's where 3 mag's build a 45°hallbach trio?
I'll try to figure that one out...
-Olaf
 
no hallbach for a while . figured ill get some conventional stuff under my belt before i start down that path. do still like the idea though

thanks for the time. the winding scheme description is not my bread and butter but i am familiar with it. looking at my notes (wich are horrible) i was using to different info sources and at the time not seeing the whole picture . learned i did.

in an effort to maintain magnet fill and use the same magnets ill make a run at a custom stator.

If i could bother you one more time ? going with the 1/2 inch diameter mags x 18 what would be the optimal slot count. ? and winding scheme ?

thanks again olaf-lampe
 
enoob said:
no hallbach for a while . figured ill get some conventional stuff under my belt before i start down that path. do still like the idea though

thanks for the time. the winding scheme description is not my bread and butter but i am familiar with it. looking at my notes (wich are horrible) i was using to different info sources and at the time not seeing the whole picture . learned i did.

in an effort to maintain magnet fill and use the same magnets ill make a run at a custom stator.

If i could bother you one more time ? going with the 1/2 inch diameter mags x 18 what would be the optimal slot count. ? and winding scheme ?

thanks again olaf-lampe

Always welcome, :)
with 18 mags, the best suitable number of slots would be 27. The diameter of the rotor is something above 93mm ( sorry no inches :oops: )
I would make the airgap as small as possible, because of the odd surface of the mags.
I would rethink the use of rounded mags here, because the inner ironring for the rotor is pretty difficult to build. Maybe you can build a simple ring and glue on the mags with ironpowder/epoxy mix up to the lower half of the mags. But I wouldn't bet on any high RPM capability...
As a prove of concept it would work, but how much would you pay for useable mags?
You can still use them as a charming bracelet :D
Olaf
BTW: If you want something easy to diy a BLDC check ebay for Studer / Revox A77 motors from old HIFI- bandmachines. I have some mags for them, too.
 
olaf-lampe said:
BTW: If you want something easy to diy a BLDC check ebay for Studer / Revox A77 motors from old HIFI- bandmachines. I have some mags for them, too.
I used to have a Revox A77 MkIII :)

revox_a77_spezial02.jpg
 
Miles said:
olaf-lampe said:
BTW: If you want something easy to diy a BLDC check ebay for Studer / Revox A77 motors from old HIFI- bandmachines. I have some mags for them, too.
I used to have a Revox A77 :)

You meant, you had had 2 potential 4kW motors! :wink:
BTW B77 also works and some capstan motors have a different mount and shaft, but actually it's the same.
I have a dozen or so of these motors, shipping to UK would be no prob 8)
Olaf
 
There's a Revox almost exactly like the one in Miles' pic about two feet from my head; can't recall the model#. Unfortunately A) it's not mine and B) I need it to continue the project of getting all my old open-reel stuff onto the computer. ;)

Another source of really nice BLDC motors is old Sony 1" VTRs used in studios. A friend of mine had a few of the VTRs scrapped from somewhere, and saved everything *except* the motors, which he tossed. :roll: If he'd thought about my bike project he'd probably have saved them for me, but it didn't occur to him for some reason. :cry:

I still have the driver boards for them; have salvaged a number of transistors, FETs, heatsinks, etc. Also some nice giant electrolytics out of the power supplies.
 
liveforphysics said:
My motor will be matching the KV of these motors, likely around 1/5th the weight, and easily half the inefficiency of these alternator/motor conversions.

So how is this motor going, been 4 months any progress? IIRC all the material have arrived?

Has anyone got a motor up and running yet? Besides enoob...

KiM
 
I´m new here in this forum. We have a projekt page in Germany called "Powercroco". One guy has
developt a bike motor few years ago.

http://www.powercroco.de/24N28P6530.html

100_2295.jpg

A6524kurve.gif


These motor was not make of best material. So if it improfe by a few detail it will be very good to built a nice small motor. :D


Mario
 
Great to have you here Sackspeed. :) I've used the powercroco site as a reference for various projects about a hundred times or so. :) Thank you for your work.
 
Luke you still working on this?
Ok so..... If my motor was liquid cooled for this chalange would we weigh it in dry?
 
Miles said:
Arlo1 said:
If my motor was liquid cooled for this chalange would we weigh it in dry?
LOL! You'd weigh it dry and you'd have to run it dry :mrgreen:
Then Im out cause I got a realy good idea! Like so good I cant belive its not already in use! :mrgreen:
 
Hy,

We build such a motor in small series for our prototype scooters.

Data:
2,8kg
Continuous: 5,69Nm at 2395rpm and 1653W in 86,3% efficiency
Max: 8,58Nm at 2252rmp and 2482W in and 81,5%efficiency

We could probably sell them at 1000$ at this stage.

http://www.youtube.com/watch?v=FvOFFiFQ8I0
 
Sorry if it's been covered but does it matter if it's a standard BLDC or a AF motor?

I'm building a AF motor and if it works I'll put the stats up here. Note that I did no maths for the design - I simply picked my desired size and went from there. Everything else is 'as much as I could fit within the desired frame'. Also nice and cheap material wise - no hallbach/litz wire craziness going on in this house!
 
Miles said:
modern_messiah said:
Sorry if it's been covered but does it matter if it's a standard BLDC or a AF motor?

No. All motor types allowed.


Would be great to actually see a motor, any motor LoL... been alot of talk since Sat Nov 28, 2009 5:05 pm
when this thread was started and IIRC not a single motor tested yet.

KiM
 
LOL AJ.

........WHO will be first?.........
 
Money permitting I'll have mine done...this year lol. ASAP would be great (was aiming for May-ish), but I'm almost scared to send my design to the laser shop for cutting. It's fairly intricate $$$$.
 
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