Rehab1 Posted March 21, 2017 Share Posted March 21, 2017 Since @meepmeepmayer posted his topic 'One more Gotway Warning) ACM Died on Me' I decided to perform an autopsy on my new ACM 1600. During my complete tear down I have found some concerns along the way about the wiring, inadequate Mosfet heat sink, and the the ability for moisture to infiltrate key electrical components of the ACM. Many of the 24 images and videos have already been posted under the 'One more Gotway Warning' topic but as my destructive journey continues I thought it best to continue my updated posts here. I sincerely hope some useful knowledge will be gained from this endeavor. I also hope I can put the wheel back together again! Link to comment Share on other sites More sharing options...
meepmeepmayer Posted March 21, 2017 Share Posted March 21, 2017 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) And don't forget your non-EUC patients or better, get them to help you. Link to comment Share on other sites More sharing options...
Rehab1 Posted March 21, 2017 Author Share Posted March 21, 2017 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! Link to comment Share on other sites More sharing options...
meepmeepmayer Posted March 21, 2017 Share Posted March 21, 2017 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). Link to comment Share on other sites More sharing options...
Hunka Hunka Burning Love Posted March 21, 2017 Share Posted March 21, 2017 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. Link to comment Share on other sites More sharing options...
meepmeepmayer Posted March 21, 2017 Share Posted March 21, 2017 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? Link to comment Share on other sites More sharing options...
Rehab1 Posted March 22, 2017 Author Share Posted March 22, 2017 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/ Link to comment Share on other sites More sharing options...
Hunka Hunka Burning Love Posted March 22, 2017 Share Posted March 22, 2017 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. 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. Link to comment Share on other sites More sharing options...
Xima Lhotz Posted March 22, 2017 Share Posted March 22, 2017 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. Link to comment Share on other sites More sharing options...
esaj Posted March 22, 2017 Share Posted March 22, 2017 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 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 ), 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 Link to comment Share on other sites More sharing options...
Rehab1 Posted March 22, 2017 Author Share Posted March 22, 2017 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 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 ), 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. Link to comment Share on other sites More sharing options...
Marty Backe Posted March 22, 2017 Share Posted March 22, 2017 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 Link to comment Share on other sites More sharing options...
Rehab1 Posted March 22, 2017 Author Share Posted March 22, 2017 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! Quite the contrary, nice day today so I will be riding in a few minutes. Link to comment Share on other sites More sharing options...
esaj Posted March 22, 2017 Share Posted March 22, 2017 25 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. No problem, but once you see the sheer amount of available options, you might get a bit discouraged (at first ). I never actually even thought how many different types of cables and manufacturers there are, until I looked around the big dealers' pages Hunka mentioned arcing in the earlier topic, I have no exact values, but in addition to the thickness, look at the voltage ratings (of the cables). Even though the battery can "only" provide up to around 84V (for 20S-packs), the transient voltage spikes could be very high when the motor is running (especially closer to the motor). In the worst case, the voltage could go momentarily high enough to strike-through between two adjacent cables, which is not a good thing (then again, I have no idea how high the voltages can get there). Of course the tradeoff is that the higher-voltage rating cables have thicker sheats (or just a material with higher strike-through voltage for the thickness), meaning either the entire cable is thicker or the actual conductor inside must be thinner to account for the thicker sheat (for given total diameter, limited by what you can get to fit)... I just took a peek at my cheapo-Aliexpress-silicone cables... none of them list any voltages, only AWG-size and temperature. Wouldn't use those in places where high voltages and/or currents go in a wheel, also it seems at least most of them have aluminum- and not copper-conductors, meaning higher internal resistance vs. copper. I have a sneaking suspicion that the manufacturers are trying to push the power of the wheels too far, especially if larger cables won't fit. The next "step" could be using even higher voltages (to produce the same power with lower current), but that also has its own problems (risk of electric shocks, the mosfets need to be beefed up to even higher voltage models etc). There's a reason that Teslas (the cars) have battery pack voltages of something like 400V, and the large national power transmission grid here uses voltages like 400, 220 and 110 kilovolts (as in 400,000 volts etc). Less current needed for high power... Quote 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 tot set the PCB in place to evaluate clearances. How are those attached? If it's just some "glue"-like thermal substance, I'd be worried that the vibration slowly causes them to come off. Btw, from that picture, it looks like the heatsink isn't exactly straight, and the mosfet-legs have bended. Probably not an issue, but do make sure that none of the actual legs on the mosfets hit the heatsink (top left corner of the image). Link to comment Share on other sites More sharing options...
Rehab1 Posted March 22, 2017 Author Share Posted March 22, 2017 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!! Link to comment Share on other sites More sharing options...
Hunka Hunka Burning Love Posted March 22, 2017 Share Posted March 22, 2017 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. Link to comment Share on other sites More sharing options...
OliverH Posted March 22, 2017 Share Posted March 22, 2017 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. Link to comment Share on other sites More sharing options...
Marty Backe Posted March 22, 2017 Share Posted March 22, 2017 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" Link to comment Share on other sites More sharing options...
Rehab1 Posted March 22, 2017 Author Share Posted March 22, 2017 4 hours ago, esaj said: I have a sneaking suspicion that the manufacturers are trying to push the power of the wheels too far, especially if larger cables won't fit. I totally agree! Unfortunately dummies like me (referring to just me) 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. 2 hours 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 I love that idea! I do think there is enough room to snake larger wires down through the shaft but it will be tight. 20 hours ago, Hunka Hunka Burning Love said: 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 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. Link to comment Share on other sites More sharing options...
Hunka Hunka Burning Love Posted March 22, 2017 Share Posted March 22, 2017 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? Link to comment Share on other sites More sharing options...
Rehab1 Posted March 22, 2017 Author Share Posted March 22, 2017 Here is a video showing the total limited amount of play (.030) between the stator and the wheel magnets.When the stator is perfectly centered the circumferential clearance between the stator and magnets is a .010. With this minimal amount of clearance if a wheel bearing were to wear out or break an EUC would bind up instantly! In the beginning of the video I am using a feeler gauge to determine the exact amount of clearance between the stator and wheel magnets when the stator is positioned all the way to the right. You will see that the surrounding magnets are super strong when I pull the stator to the left and then back to the right! Being there is a total of .030 clearance I used .010 thickness business cards to align the stator circumstantially. The GW modifications should be completed in approximately 10 years. Link to comment Share on other sites More sharing options...
steve454 Posted March 22, 2017 Share Posted March 22, 2017 @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. Link to comment Share on other sites More sharing options...
Marty Backe Posted March 23, 2017 Share Posted March 23, 2017 1 hour ago, Rehab1 said: I totally agree! Unfortunately dummies like me (referring to just me) 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. 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? Link to comment Share on other sites More sharing options...
steve454 Posted March 23, 2017 Share Posted March 23, 2017 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. Link to comment Share on other sites More sharing options...
steve454 Posted March 23, 2017 Share Posted March 23, 2017 1 hour ago, Rehab1 said: the last photo is a wonderful piece of art work. It is, but to really look good, there should be about 50-75% more copper color there. Link to comment Share on other sites More sharing options...
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