Rehab1

Gotway ACM 1600 Autopsy and Mods

316 posts in this topic

You should repeat all your posts here, they contain good info (just don't delete them from the other topic or that will become even more unreadable - add a link to here in your first post there).

I'm also impressed/scared by how nonchalantly you dissect your new expensive wheel (no chance of return with ali might help you there though):clap3:

And don't forget your non-EUC patients:P or better, get them to help you.

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5 minutes ago, meepmeepmayer said:

You should repeat all your posts here, they contain good info (just don't delete them from the other topic or that will become even more unreadable - add a link to here in your first post there).

 

Thanks but I don't want to diminish the huge importance of your topic! I will just mosey along and keep investigating and learning as much as possible about our machines. Hopefully something good will come out of it. I do have a huge mess of parts on my bench!:P

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Don't want to spam the other thread with OT further, this question belongs here. In pic 21 (open motor), where does the actual rotation take place? Around the axle (then how do the cables work?). The ring with the holes on the outside?

And I still think you should summarize your findings itt. When all is said and done, I'm going to ask to have the other thread moved to the GW forum (it has higher short term visibility in General, but longer term here and in the end it belongs here).

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Posted (edited)

I've always wondered how the motor spins, but after viewing a few videos and theorizing it out, I think the inner part doesn't move at all relative to the pedals.  The outer tire along with the rim with the attached rectagular magnets rotates around where the copper coils are wound.  There is an amazingly small amount of clearance between the magnets and the opposing surfaces.  When the motor covers are on they spin with the rim around the axle where there are two bearings.  That allows all the wiring to remain stationary along with the axle itself while the outer motor covers with the tire and rim spin around.

If you imagine a gyroscope (I had one as a kid) on it's side, but instead of the inside part spinning, the outside spins around the inside stuff.  Where the axis meets the outer ring (motor cover) are where the bearings are located so the axis can pass through inside the bearings and lock onto the pedals.

eafc_original_gyroscope.jpg

Edited by Hunka Hunka Burning Love
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That makes sense. I'm just surprised you hear absolutely no sound from that rotation (ball bearings or such). Or is that that motor sound you hear at higher speeds?

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2 hours ago, Hunka Hunka Burning Love said:

I've always wondered how the motor spins, but after viewing a few videos and theorizing it out, I think the inner part doesn't move at all relative to the pedals.  The outer tire along with the rim with the attached rectagular magnets rotates around where the copper coils are wound.  There is an amazingly small amount of clearance between the magnets and the opposing surfaces.  When the motor covers are on they spin with the rim around the axle where there are two bearings.  That allows all the wiring to remain stationary along with the axle itself while the outer motor covers with the tire and rim spin around.

Yes, that is how It should function but when I reassemble the wheel everything will remain stationary but the peddles will probably spin. 

 

2 hours ago, meepmeepmayer said:

 

Don't want to spam the other thread with OT further, this question belongs here. In pic 21 (open motor), where does the actual rotation take place? Around the axle (then how do the cables work?). The ring with the holes on the outside?

 

 Check out @esaj EUC Motor Drive topic. It is a wealth of information, http://forum.electricunicycle.org/topic/3909-euc-motor-drive/

 

 

 

 

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Posted (edited)

I think the two are sealed bearings so they should be pretty quiet.  I believe our EUC use brushless outrunner motors.  The hum you get is from the electrical frequency of the different coils being activated?  I'll let someone else who knows the answer explain why electric motors make a high pitched sound.  :smartass:  If you listen to a computer fan it's pretty quiet too since there are no contacts other than the bearing.  Electromagnetic drive can be pretty quiet.

I was going to say it might be best not to remove both sides of the motor covers at the same time in order to help maintain alignment?  Although I hear you can place cut up poker card shims to help place on one side cover and then remove them to do the other side.

Edited by Hunka Hunka Burning Love
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Posted (edited)

Found some places where you (might) buy motor cable by M if you wanted to change to a bigger mm2 to cope with current. I have not bought from them or know anything about the links. Could not find the same cable with with Aliexpress och DH gate, might be searching for the wrong thing.

Its Chinese but google translate is your friend :)

https://nxtmarket.info/item/14237135816

http://www.86mall.com/p/tie-fu-long-gao-wen-xian-tong-kun-hui-er-te-KFVR3X155X02dian-dong_42219591243

https://world.taobao.com/item/37416796283.htm?fromSite=main  (this site recommends 3mm2 for 2000W motor and 500W for 1,5mm2) I think the diameter of the cable 1,5mm2 is 5,7mm and 3mm2 7,7mm but thats just a guess from the pictures!

 

"Funny" thing with all cables, its silicon wires (200degrees C conductor temp) for the engine cables, but the cable is then protected by a PVC sleeve, max temp 80-105 depending on PVC.

So max temp is then 105 degrees or the PVC will break / melt with time.

 

Edited by Xima Lhotz
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Posted (edited)

41 minutes ago, esaj said:

If you want to go totally overkill, there's always something like Helukabel's Helutherm 400, temperature range is -60...+400C (450C for short periods), available in sizes between 0.5mm2 and 240mm2. I think the sheathes had something like fiberglass in them, so maybe not that good for when it needs to bend to tight places :P  Ölflex had some teflon-based cables that went up to +260C or so, there are some special cables that go above 500C... ;)

But in more serious note, even if the cables could take it, something else would give up if there's stuff heating to hundreds of degrees inside the mainboard compartment ;)  Using thicker cables, the internal resistance, and thus power loss, in the cable should drop, and it won't heat as much. Electronics component suppliers have wide variety of cables (Digikey has something like closer to 180,000-200,000 products under Cables & Wires, depending which countrys pages you're looking :D), handy filtering tools to find what you're looking for, and except for the special cables, like those mentioned above, they're usually not that expensive. In this case you probably won't want to second-guess the quality, so I'd say that the safest bet is to get from a reputable large dealer, rather than Aliexpress or such. 

http://www.digikey.com/products/cables-wires/en

http://www.digikey.fi/products/en/cables-wires/single-conductor-cables-hook-up-wire/474

http://www2.mouser.com/Wire-Cable/Hook-up-Wire/

http://www.newark.com/cable-wire-cable-assemblies  (Farnell outside US)

...And probably many others, Mouser & Digikey are probably the largest electronics (as in components and related stuff, not toasters, TVs etc ;)) dealers worldwide

 

Your an awesome library of valuable information! Many thanks! I will begin researching your cable resources tonight. I do like the idea of a Teflon cable!. I still need to evaluate the exact diameter of the conduit traveling through the wheel shaft to see how much room I have for a larger cable. 

41 minutes ago, esaj said:

But in more serious note, even if the cables could take it, something else would give up if there's stuff heating to hundreds of degrees inside the mainboard compartment ;)

I purchase some copper mosfet heat sinks that hopefully will dissipate the heat more efficiently. Currently they are just tacked in place over the top tier of the (6) mosfets.  I still need to set the PCB in place to evaluate all of the clearances.

 

Edited by Rehab1
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6 minutes ago, Rehab1 said:

Your an awesome library of valuable information! Many thanks! I will begin researching your cable resources tonight. I do like the idea of a Teflon cable!. I still need to evaluate the exact diameter of the conduit traveling through the wheel shaft to see how much room I have for a larger cable. 

I purchase some copper mosfet heat sinks that hopefully will dissipate the heat more efficiently. Currently they are just tacked in place over the top tier of the (6) mosfets.  I still need to set the PCB in place to evaluate all of the clearances.

 

I just realized why you've been going down this rabbit hole - right now the weather sucks in your part of the country ;)

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9 minutes ago, Marty Backe said:

I just realized why you've been going down this rabbit hole - right now the weather sucks in your part of the country ;)

I'm like @Hunka Hunka Burning Love, we both love bunnies!:laughbounce2: Quite the contrary, nice day today so I will be riding in a few minutes.  :)

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5 hours ago, Xima Lhotz said:

Found some places where you (might) buy motor cable by M if you wanted to change to a bigger mm2 to cope with current. I have not bought from them or know anything about the links. Could not find the same cable with with Aliexpress och DH gate, might be searching for the wrong thing.

I am falling behind in thanking everyone for their help! Thanks!

OMG I am now in Cable Heaven!!:)

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1 minute ago, Hunka Hunka Burning Love said:

It would be nice if EUC makers used a slightly larger diameter bearing and axle.  Since they need to have a hollow axle on one side, this would allow the outside walls to be thicker, allow larger gauge wiring to pass through, and reduce the odds of axle breakage that we often see in some KS14 KingSong wheels.  Or going with Marty's idea of hollowing out both sides of the axle, one could pass motor wires through one side and hall effect sensor wires through the other.  They would have to pass one set of wires over and through the shells though to reach the controller, but a simple connector for the hall sensor wires would do the trick as they don't carry much voltage anyways.  A larger diameter axle and bearing setup would likely be the simpler way to go.

Bearings are getting expensive with bigger diameter. The bearings used today are cheap and available in different quality/ price categories.

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15 minutes ago, OliverH said:

Bearings are getting expensive with bigger diameter. The bearings used today are cheap and available in different quality/ price categories.

Relative to the cost of a $1500 - $2500, surely the bearings are not expensive. I would pay the difference if they advertised, "Now with bigger and stronger bearings"

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:blink: I I think they need you on the Gotway production line floor as chief quality control inspector.  You can test ride Gotways off the line all day!  Ever want to move to a different country?  :w00t2:

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@Rehab1 thanks for the great photos!  I never knew the wheel had spokes before, all the other photos I've seen elsewhere only show the motor with the covers on.  Just by looking, it looks pretty well made, but I know very little, just that it looks good.  I always thought that the motor coils were closer together, near the axle.

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1 hour ago, Rehab1 said:

I totally agree! Unfortunately dummies like me (referring to just me:P) buy a wheel that is the suppose to be the greatest and fastest with the largest Mh battery and then become the guinea pigs for shaking out all of the problems. Oh well...it will be be an nice educational adventure.

 

I love that idea! I do think there is enough room to snake larger wires down through the shaft but it will be tight.

Yes I head of that! There is only .010 clearance between the outer perimeter of the stator and the magnets mounted on the wheel. I used my .010 thickness plastic business cards to perform the alignment. I am not at the stage of reassembly yet but it was a hurdle I needed accomplish sooner or later. Here are some photos, some with my colorful business cards placed between the stator and magnets. The 1st and 3rd photo depict a feeler gauge I used between the stator and magnets to determine the exact clearance I would need. The 4th photo shows a micrometer measuring the thickness of my business card and the last photo is a wonderful piece of art work.:P

 

Great pictures. So, with your critical eye, how do you rate the overall construction and quality of the motor? Do you think it's a repurposed motor or does Gotway build it?

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29 minutes ago, Marty Backe said:

repurposed motor or does Gotway build it?

To me it looks like an electric scooter motor that Gotway used for it's self balancing electric unicycle.  But what does it matter?  It is the programming that controls it that matters.  Oh wait.  It would be much better if it was designed from the ground up to use in a one wheeled device.:huh:

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1 hour ago, Rehab1 said:

the last photo is a wonderful piece of art work.:P

It is, but to really look good, there should be about 50-75% more copper color there.

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