ES DIY Motor Challenge

[olaf-lampe]

... 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

[enoob]

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 . viewtopic.php?f=30&t=14264

[olaf-lampe]

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

[enoob]

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

[olaf-lampe]

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 )
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
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.

[Miles]

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

[olaf-lampe]

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!
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
Olaf

[amberwolf]

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. 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.

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.

[AussieJester]

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

[karma]

any updates

[sackspeed]

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




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.


Mario

[Miles]

Welcome Mario!

Coincidentally, I posted a link to that motor 3 days ago, as an example of a 24N 28P winding scheme...

[sackspeed]

sorry Miles,

I see it. The problem of the design are the stator iron sheets. You can get only sheets of 0.5 mm. With 0.35 or 0.2 mm sheets the motor
will work fine. Perhaps you know this site at Powercroco?

http://www.powercroco.de/24N28P6520.html

[Miles]

Mario,

Yes, I know the site. I actually corresponded with Dr Okon about this motor, five or six years ago.

[liveforphysics]

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.

[Arlo1]

Luke you still working on this?
Ok so..... If my motor was liquid cooled for this chalange would we weigh it in dry?

[Miles]

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

[Arlo1]

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

Then Im out cause I got a realy good idea! Like so good I cant belive its not already in use!

[Miles]

There's usually a reason.....

Give us a clue.........

[existerion]

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

[modern_messiah]

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]

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.

[AussieJester]

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

[Thud]

LOL AJ.

........WHO will be first?.........

[modern_messiah]

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 $$$$.