New guy, new to me Magic Pie

[ZAXBÎX]

Hi all,

  Got me a free Magic Pie a bit ago. Got her torn apart; burnt controller, questionable bearing, replaced phase wires to setup for an external controller, installed a thermistor.  No real questions at the moment.  Just a post, so hopefully I can lurk a little more efficiently.  By the looks of it, this little Betty should be a torque troll (not quite a monster).  Thinking FOC ~40A controller, 26" wheel.  Looking at the windings I don't think going over 50-60v will be efficient and anything more than continuous 30A phase current will cook it.  Only time and smoke will tell.  Just another winter project.

[ZAXBÎX]

I tried a reply to my own post. Maybe that doesn't work? Not a tech guy, just an old wrench, with a Walmart phone. Maybe this one works, maybe I try the real one.

Please excuse my ignorance and thank you for your time, ZAX

[ZAXBÎX]

Okay, that worked.?

Okay boys and girls...  Got me a question for this fine community; where can I get a decent and affordable bearing?  I'm working on a Magic Pie 3.  I need the large bearing; 85x120x18mm, 6917-2RS, sealed, unless my measurements are incorrect.  Stumped my local Napa, which doesn't happen and they're looking into it, that being said my go-to guy wasn't there.  I'm in the US, Colorado to be specific.

Thought I'd toss in a couple pics of her.

Thanks all, ZAX

[ZAXBÎX]

Gunna put another thermistor in what looks like an extra notch for a hall sensor in the last picture.  A pic of me separating the cover.

Thanks for your time, ZAX

[ZAXBÎX]

Gotta figure out how to resize pictures.  Anyway, another with wedges.

Thanks, ZAX

[ZAXBÎX]

Hey folks.

I've got part of a butchered MP harness that's of no use to me.  Maybe someone else can put it to use.  I'm buying if you're flying.

Thanks, ZAX

[Sam.Vanratt]

Hello ZAX
I did a repair on my first "drawned" MagicPie3 (you looks like mine, so maybe a MP3 itself). When cleaning, drying the damaged one I replaced the HALL sensors as the original were said to die quickly. I replaced the bearings as well with SKF "low friction" ones, changed the 1,5mm^2 phase wires with decent 4mm^2 and took the time to seal the coil with special glew and have it baked (so the glew get hard).
In my first refit I used again the MP3 internal controller, after two years this one failed and I replaced it with another internal one; one year after that the controller died again and I switched (in 2016) to an external VESC which works since then as FOC (=sinodial) controller. Since that the (enhanced) MP3 is silent, runs very smooth (with no load about 180mA current at 30V).

I did a bit of report three month ago when my second MP3 had controller failure (again) and I tried to go for an Kelly KBS36051X, but finally going for the VESC again. The second one is with original bearing and no sealing of the coils, so I have a direct comparison.

While taking a lot of time and resources, I'm very happy with the modification. The bearing is quite cheap (about 30EUR for the big one, the small one about 15EUR), the cables costs just effort, the sealing itself would be very cheap apart from the manpower and finally the VESC + a sealed chamber for about 150EUR. The Original ESC costed about 50EUR replacement, while the Kelly would be about 60USD+Shipping and is said to be very sturdy and reliable (which I believe as I've seen the quality of the used parts).

Used with 50V and it's allowed 50A (not with the 1,5mm^2 cables!) the MP3 could give you 75Nm which is not the best possible, but a lot of beef. Apart from it's high weight the MP3 is still my prefered choice (would the controller be more reliable). My first one have now about 50.000km ride, while my second one is nearly 100.000km since 2011. I'm using it in a trimmed 24V/10A setting with rekuperation enabled and in both versions as front drive which is very apealing.

Remember to grease/insulate the openings so no moisture get in. I used silicon salt packs to get moisture under  control.

I'm into electronic myself, but mechanics is a very weak spot in my "tool chain" :-) so every change is taking a lot of probing and tinkering until it works.

Cheers
Sam

[ZAXBÎX]

Thanks for the reply Sam!

Any chance you have part numbers for the SFK bearings you used?
I was thinking of replacing the Hall sensors while I have it apart.  I've had good luck with Honeywell sensors in the past.  What type of sensors did you use, and a part number perhaps?

Thank you to all and for your time, have a wonderful day; ZAX

[ZAXBÎX]

Gee;  I wonder why this guy won't work?  He-he.

  ZAX

[Sam.Vanratt]

Thanks for the reply Sam!

Any chance you have part numbers for the SFK bearings you used?
I was thinking of replacing the Hall sensors while I have it apart.  I've had good luck with Honeywell sensors in the past.  What type of sensors did you use, and a part number perhaps?

Thank you to all and for your time, have a wonderful day; ZAX

Hello ZAX
the controller looks exactly like my old MP3 one.
The HALL I used was the "Honeywell SS41 latching bipolar hall sensor"; the attribute Latching is here very important
The SKF I used is not really known to me right now, but I did notice the "way" I took:

SKF: 6202-2RSH
61812-2RS1

As there were more than one MP3 (the controller had a few revisions) and even the MagicPie 2 was there with an internal controller this info may be on my special version (build ~2010-2011).

Afair: the bearing designation is always printed on the front side outer shell of a bearing.

Cheers
Sam

[Sam.Vanratt]

Gee;  I wonder why this guy won't work?  He-he.

  ZAX

Most MP3 controllers died due to a defect in one of the three halfbridges, I talked with one of the GM technicians in 2012 about it as two MP3s were defective, which shuddered my reliance in GM at that time. Your one lost one capacitor (blown?!), but debugging a 30EUR controller which is build hard on the specs (used cables are too thin to take the current, the FETs are 60V types which works with a typ. 48V battery on the edge of destruction, the caps are 63V types) and sealed is beyond my repair will.

If you are willing you could use the GoldenMotor BAC-028X controller. If you want years of troublefree running, I'd go for a Kelly or with my knowledge now the VESC. With four defective int. Controller in about 5 years it's not my understanding of electronic to go again just to have an internal controller. Gary in Canada is sure to help you with replacements from GM.

Cheers
Sam

[ZAXBÎX]

Thanks for the input Sam!

I have no intention of using the dainty busted up internal controller.  Novel idea at best, in my opinion.  I might use it for a cover plate, auger out a slot big enough for the wires.  Unless someone can put it to use, I can always make a blank from aluminum plate.

The designation on the bearings of this golden motor MP3 are as follows.

Right, drive side, small bearing-. 6302Z.   15*42*13mm
Left, brake/controller side, large bearing-  6917RS.   85*120*18mm

Going replace the large one, due to drag in it; and the small one, in favor of a sealed bearing.

Still waiting to hear from my parts guy about a 6917 bearing.


Just looked through my bag of tricks, found a couple dozen Honeywell sensors marked s41.  Gotta love being a hoarder.

Thanks again Sam and to all a good day, ZAX

[Sam.Vanratt]

This is one of my threads to my recycling:
https://goldenmotor.com/SMF/index.php?topic=6634.0

[Bikemad]

Used with 50V and it's allowed 50A (not with the 1,5mm^2 cables!) the MP3 could give you 75Nm which is not the best possible, but a lot of beef.

My original Magic Pie (Version I) with a modified controller produced a crudely measured stall torque of ~93Nm whilst drawing a current of 65.94A @ 25.6V.

The torque from the Magic Pie is a lot more impressive when you put lots of Amps into it. The maximum current that I recorded with the thickened up additional shunt was 97.75 Amps using a 14s LiPo pack, shortly before the controller finally died:



I realise it's probably a bit late now, but I thought I would re-post the following bearing details for the Magic Pies:



Alan
 

[ZAXBÎX]

Thanks Alan, proper!

Almost 100A: wow, wonder what the phase current was and the duration as well as the load. Temperatures?

With no experience in the Magic Pie realm, I'm very impressed with the concept of the design.  Though a wider stator and thinner laminations with more meat for heat, would be the cat's meow.

Thinking about a platform for this little torque troll...  Have a well built short wheelbase 26" mountain bike not in use, it'd be a wheelie machine.  Drift trike, big wheel style, would be fun.  Maybe something more utilitarian, like a stretched or cargo style frame.  I do have a 26" 36h rhino lite hoop hanging in the shop. 

Some redneck testing of the MP in the rear basket of my E-powered grocery getter.

Thank you Alan and to all a great day, ZAX