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Gotway ACM 1600 Autopsy and Mods


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No real updates other than waiting for my new motor. I had to post this video showing how the copper wire is routed throughout the motor.

I started peeling away the waxed thread that binds all of the wires together in a cohesive fashion and then pulled on the copper wire to try and gain come semblance of the copper winding pattern.  

I found that in addition to the tightly wound copper coils there are numerous copper jumpers (not sure exactly what to call them) weaved through the coils at an interval of 7 spaces each.. The wire jumpers converge into a bundle of 3 that are soldered together. There is certainly a degree of talent that goes into winding these motors!

 

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23 minutes ago, Rehab1 said:

No real updates other than waiting for my new motor. I had to post this video showing how the copper wire is routed throughout the motor.

I started peeling away the waxed threaded that binds the wires together in a cohesive fashion and then pulled on the copper wire to try and gain come semblance of the copper winding pattern.  

I found that in addition to the tightly wound copper coils there are numerous copper stringers (not sure exactly what to call them) weaved through the coils at an interval of 7 spaces each.. The wire stringers converge into a bundle of 3 that are soldered together. There is certainly a degree of talent that goes into winding these motors!

 

You can fix this dude!  I will post more info. but here a cool GIF for your enjoyment!

 

4-pole-bldc-motor.gif

JAMO_0-33Wi10Abig.gif

BM-3-LRK Winding Diagram1.jpg

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1 hour ago, Rehab1 said:

I found that in addition to the tightly wound copper coils there are numerous copper jumpers (not sure exactly what to call them) weaved through the coils at an interval of 7 spaces each.. The wire jumpers converge into a bundle of 3 that are soldered together. There is certainly a degree of talent that goes into winding these motors!

Funny how things "converge" at times, I was reading some articles and application notes on "Field-Oriented Control" (a way of driving Permanent Magnet Synchronous Motor, or PMSM) trying to figure it out... anyway, when I saw your mention of the "jumpers", things clicked. I tried looking for "PMSM winding" in Google image search, and:

energies-08-04920-g003-1024.png

 

It turns out that the difference between a "basic" BLDC and PMSM is in the windings (and of course the driving algorithm, which is much more complex for PMSM):

From  https://e2e.ti.com/support/microcontrollers/c2000/f/171/p/85876/296577#296577

The differences come from construction. BLDC's have concentrated stator windings, while PMSM's have distributed stator windings. The latter are more expensive for manufacture. Before anybody involved in machine design point out, I should say that with careful design of rotor and stator iron of BLDC you can come near sinusoidal BEMF. 

It would seem that the "jumps" are used in distributed stator winding, although I'm not 100% sure on that either, the "humble" electric motors are complex beasts...

high-power-and-low-cost-solution-stator-

 

From NXP's application note https://www.lpcware.com/content/nxpfile/an11517-field-oriented-control-foc-pmsm-motor-using-lpc15xx  (AN11517: Field Oriented Control (FOC) of PMSM motor using LPC15xx):

2.1 PMSM and BLDC difference
PMSM and BLDC motors are both permanent magnet-based motors with the same basic
structure, consisting of permanent magnets on the rotor and windings on the stator. The
main difference between BLDC and PMSM is the drive signal for which it is designed. A
PMSM is designed for a sinusoidal drive, while a BLDC is designed for a trapezoidal
drive. The advantage of a sinusoidal driven motor is the minimized torque ripple that
results in a much quieter motor, both electrically and mechanically. The current
harmonics are in the switching frequency range resulting in a lower audible noise, lower
motor core losses and a reduced current peak. The disadvantages are higher switching
losses due to an extra phase that has to be powered constantly.
 

Sooo... basically the motor-drive -bit I wrote a long seems to be at least partially wrong, as it talks of the drive from the viewpoint of BLDC (trapezoidal control). On the other hand, the electronics (mosfet half-bridges etc.) and the basics of the motor movement (magnetic attraction/repulsion) are pretty much the same, "only" the motor winding and the control algorithm would seem to differ. Probably you could drive a PMSM with trapezoidal control too, but it wouldn't work as well?

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http://www.bavaria-direct.co.za/scheme/common/

 

here is the calculator for the poles and teeth combination. I put an example of a 54-50 2layer Delta.  Not sure how is your motor wired. you need Delta or Yee pattern. but I dont know which

http://www.bavaria-direct.co.za/scheme/calculator/

@Rehab1

it will show step by step animation of how to wire the whole thing.

54-50.PNG

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8 minutes ago, Carlos E Rodriguez said:

@Rehab1 I think your motor is wired as a 2 layer YIE configuration but I need others to confirm.

 

Wye_diagram_sm.gif

54-50-2layer-yie.PNG

I tried to count the slots from this picture, but it's pretty hard :P 

5HWg71O.jpg

I think there are more than 54 slots? Rehab can probably count them from the real thing and enter the values in the calculator... But also the amount of turns and the wire gauge would have to be known to not alter the characteristics of the motor? The mainboard firmware is likely "tuned" to the original motor characteristics...

 

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39 minutes ago, esaj said:

I tried to count the slots from this picture, but it's pretty hard :P 

5HWg71O.jpg

I think there are more than 54 slots? Rehab can probably count them from the real thing and enter the values in the calculator... But also the amount of turns and the wire gauge would have to be known to not alter the characteristics of the motor? The mainboard firmware is likely "tuned" to the original motor characteristics...

 

Agreed. Count the slots and magnets. Get a new picture from the calculator. 

- unsolder the three looms that are wired together. 

-with a DMV do a continuity check on the cut wire and the A B C phase wires (one at a time) that connect to the controller and mark that.

-with a DVM do a continuity check on the cut wire and find the pigtail that you just unsolder. It will be one of the three.

-with a DVM confirm the phase end and the pig tail end correspond. This is a verification. 

-at this point now you know which phase is broken. 

-start unwrapping and I would mark each slot with clockwise and counterclockwise as you unwrap. Also count the turns .

-buy new wire. 

-figure out which wiring scheme matches your motor (delta,yie,1layer2layer). Unwrapping the broken phase will confirm 100%.

- rewind wiring and get riding. 

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I would venture to say that it's likely a lot easier said than done.  I've re-watched Rehab1's video over and over trying to make sense of the wiring, and I would say that unless you know what you're doing from the start, it's probably not going to be an easy task to undo things and put it back together properly with the correct tightness.  If the Gotway motor supplier could provide an instructional video then sure that would make life that much easier, but I have a feeling to replicate the wiring loom pattern is going to be quite challenging and time consuming with an uncertain result.  It would require detailed photographs of both sides and video of the disassembly and very careful reassembly.

I'd compare it to trying to take apart an intricate transmission without a manual, prior experience, or video instruction and then reassembling it.  Quite daunting!  Factoring in the amount of money that Rehab could be earning doing his professional duties and the fact he already has ordered a replacement motor, I think it would be more in the realm of one of those let's see if I can do it spare time efforts rather than a primary mission effort if that makes any sense.  I'm not saying that it's impossible, but whether it's very practical to spend that much time doing so is the big question.  I guess having a spare motor might be handy, but these don't tend to burn out usually... resale would be limited... scientific curiosity and challenge might be worth it?  If it doesn't work in the end though that might be time and further effort wasted?

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10 minutes ago, Hunka Hunka Burning Love said:

I would venture to say that it's likely a lot easier said than done.  I've re-watched Rehab1's video over and over trying to make sense of the wiring, and I would say that unless you know what you're doing from the start, it's probably not going to be an easy task to undo things and put it back together properly with the correct tightness.  If the Gotway motor supplier could provide an instructional video then sure that would make life that much easier, but I have a feeling to replicate the wiring loom pattern is going to be quite challenging and time consuming with an uncertain result.  It would require detailed photographs of both sides and video of the disassembly and very careful reassembly.

I'd compare it to trying to take apart an intricate transmission without a manual, prior experience, or video instruction and then reassembling it.  Quite daunting!  Factoring in the amount of money that Rehab could be earning doing his professional duties and the fact he already as ordered a replacement motor, I think it would be more in the realm of one of those let's see if I can do it spare time efforts rather than a primary mission effort if that makes any sense.  I'm not saying that it's impossible, but whether it's very practical to spend that much time doing so is the big question.  I guess having a spare motor might be handy, but these don't tend to burn out usually... resale would be limited... scientific curiousity and challenge might be worth it?  It it doesn't work in the end though that might be time and further effort wasted?

Agreed. But it's basically wax on wax off. The pattern is industry standard and the calculator app shows step by step how to wind. 

Yes considering USA income it is only advisable as a project. Then you can buy the $35 controller from mricroworks and 3D print a case and you have a hot rod wheel. Lol. 

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My head is spinning! I love all of the research @Carlos E Rodriguez and @esaj! Thanks a bunch!! @Hunka Hunka Burning Love makes good points especially the time consumption. For approximately $200 I will have a new motor ready to go. It would be nice to have a video as I would like to try it. I hate the idea that a GW lady can wind these suckers and I can't!:crying:

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6 minutes ago, Rehab1 said:

My head is spinning! I love all of the research @Carlos E Rodriguez and @esaj! Thanks a bunch!! @Hunka Hunka Burning Love makes good points especially the time consumption. For approximately $200 I will have a new motor ready to go. It would be nice to have a video as I would like to try it. I hate the idea that a GW lady can wind these suckers and I can't!:crying:

Yeah! Exactly. See if you can buy the wire for cheap from aliexpress. It's already broken so you might be surprised. 

Otherwise i would take it if your hands if I lived close by. 

I live in Wisconsin. 

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2 hours ago, esaj said:

I found this sentence from the above article to be interesting:

Some of the disadvantages of BLDC's are high cogging torque (air gap between rotor and stator is not constant), and high torque ripple resulting from simple commutation principle.

Why is the air gap between the rotor and stator not constant? 

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16 minutes ago, Carlos E Rodriguez said:

Yeah! Exactly. See if you can buy the wire for cheap from aliexpress. It's already broken so you might be surprised. 

Otherwise i would take it if your hands if I lived close by. 

I live in Wisconsin. 

For the pure advancement of EUC science I will gladly ship it to you once the other motor arrives! PM me an address. I will be shipping from Ohio.  Would you be willing to a shoot video during the rewinding phase so we all can learn?

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3 hours ago, Carlos E Rodriguez said:

You can fix this dude!  I will post more info. but here a cool GIF for your enjoyment!

 

4-pole-bldc-motor.gif

JAMO_0-33Wi10Abig.gif

BM-3-LRK Winding Diagram1.jpg

@Rehab1  look at the animated GIF Arango red yellow animation. 

As the stator spins it gets closer and then farther from the magnet as it spins over every magnet so the air gap gets smaller and bigger. On a brush motor you have only two big magnets for example so over the surface the stator is in constant distance from the magnet as it spins. The cogging on a brush motor is achieved by the commutation of the brushes.  On a BLDC motor the commutation is done by combination of the many magnets in place of the commutation contacts and the MOSFETS. 

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5 minutes ago, Rehab1 said:

For the pure advancement of EUC science I will gladly ship it to you once the other motor arrives! PM me an address. I will be shipping from Ohio.  Would you be willing to a shoot video during the rewinding phase so we all can learn?

Sure. will do. 

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2 minutes ago, Carlos E Rodriguez said:

As the stator spins it gets closer and then farther from the magnet as it spins over every magnet so the air gap gets smaller and bigger. On a brush motor you have only two big magnets for example so over the surface the stator is in constant distance from the magnet as it spins. 

Ok...that make sense! My mind was wrapped around some type of magnetic field line distortion.

 

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I am beginning to understand. This photo is similar to the one @Carlos E Rodriguez posted. So the jumper sequence in this photo is 3 (i.e., The A motor wire jumps from pole 1 over to 4 and then to 7. B wire from 2 to 5 to 8 and C from 3 to 6 to 9. Interesting!

I need to count the number of slots tomorrow. 

 

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Both Ian and Jason will be carrying the ACM motors in a few weeks. I plan to purchase the motor from Jason due to the close proximity but I saw this on Ian's site a few minutes ago. Interestingly the replacement motor will fit 4 different wh versions of the ACM. 

Gotway ACM Motor Unit

Stock replacement motor unit direct from Gotway. Fits the 680, 820, 1300 and 1600wh version of the ACM.

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3 minutes ago, Rehab1 said:

Both Ian and Jason will be carrying the ACM motors in a few weeks. I plan to purchase the motor from Jason due to the close proximity but I saw this on Ian's site a few minutes ago. Interestingly the replacement motor will fit 4 different wh versions of the ACM. 

Gotway ACM Motor Unit

Stock replacement motor unit direct from Gotway. Fits the 680, 820, 1300 and 1600wh version of the ACM.

Wow, very affordable!  Amazing it's so cheap.

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21 minutes ago, Rehab1 said:

Both Ian and Jason will be carrying the ACM motors in a few weeks. I plan to purchase the motor from Jason due to the close proximity but I saw this on Ian's site a few minutes ago. Interestingly the replacement motor will fit 4 different wh versions of the ACM. 

Gotway ACM Motor Unit

Stock replacement motor unit direct from Gotway. Fits the 680, 820, 1300 and 1600wh version of the ACM.

Lol. The wh has nothin to do with he motor. Lol. The wh just tells you how much energy the battery pack has. 

84v 1p,2p,3p,4P. The more p the more wh. 

That being said the bigger motor will eat up the wh faster. And the bigger motor will also need more P because it needs more amps to work. 

You think they are using the same motor for the 84v and the 67v?

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2 hours ago, SuperSport said:

Wow, very affordable!  Amazing it's so cheap.

I thought so! Can't imagine what a shop (if I could find one) would charge but certainly more the $200!

 

2 hours ago, Carlos E Rodriguez said:

You think they are using the same motor for the 84v and the 67v?

Sort of what I was alluding to. The 680 and 820 do not come 84v. 

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Just now, SuperSport said:

I know the MSuper uses the same motor on 67.2 and 84. 

So do they use a voltage regulator?

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