Rehab1

Gotway ACM 1600 Autopsy and Mods

312 posts in this topic

Oh wow this opens a new can of worms... custom rewinding, for maybe better torque or so (if the rest of the components support it). Thank god I don't want to spend any more money, otherwise I might be inspired to get a custom high torque ACM for the mountains.

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Posted (edited)

2 hours ago, Rehab1 said:

I decided to drop off the motor to a local highly revered electric motor company. The inside of their building was a bit of a shocker, a bit disorganized, but they are suppose to do excellent work. They will call me with a price for rewinding it first. Once Ian receives the price for a new motor from Gotway  I will make the determination  on which avenue to take.

Picture 2 depicts their work shop with my motor, picture 2 shows the lacquer buckets and 3 depicts the coil winders.

 

Good luck, but the time and effort involved in fixing the motor in a local American shop has got to be more than a new stripped down motor from Gotway. Then again their hourly rate may be commensurate with your hourly rate on your ACM rebuild :laughbounce2: 

Edited by Marty Backe
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Maybe they can wire a motor to pull more energy and that runs at a faster speed :-)

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2 hours ago, Marty Backe said:

Good luck, but the time and effort involved in fixing the motor in a local American shop has got to be more than a new stripped down motor from Gotway. Then again their hourly rate may be commensurate with your hourly rate on your ACM rebuild :laughbounce2: 

The local shop I use has all Chinese women winding the coils so the hourly rate is quite reasonable! ;)

You are most likely  correct! Hopefully both Ian and the motor rebuilder will have some idea of cost  in the next few days!

2 hours ago, electric_vehicle_lover said:

Maybe they can wire a motor to pull more energy and that runs at a faster speed :-)

I'm not sure if they can squeeze out any more power. Any ideas up your sleeve to make it run faster and more efficient without putting the rider (me) at risk?:cry2:

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Posted (edited)

What wattage rating are the ACM motors?  This one is reasonably priced.

https://www.ewheels.com/product/v8-replacement-motor/

I wonder whether the number of stator teeth are the same in some of these motors.... it would be nice to be able to swap an InMotion motor say for the Gotway one...

@electric_vehicle_lover Could you tell us how different motor specifications are accounted for in control board firmware?  Say if one wheel has X number of stator teeth while another has X+Y number of stator teeth, how does that affect the motor control calculations?  Are there other limits as well that are programmed in?

I suppose that the axle design is likely to be different so even if the motor itself were compatible the pedal supports probably wouldn't be a direct fit...

Edited by Hunka Hunka Burning Love
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3 hours ago, Hunka Hunka Burning Love said:

What wattage rating are the ACM motors?  This one is reasonably priced.

https://www.ewheels.com/product/v8-replacement-motor/

Thanks Hunka! The wheel from the outside looks identical, brackets, axle nut even the wire color codes! Interesting!

@Jason McNeilIs it possible that Inmotion and GW use the same motor manufacturer? Do you have any V8 motors lying around with the covers removed? If so could you please take some close up photos of both sides of the motor depicting the stator, coil windings, hall sensors, magnets? If not could you please maesure the axle diameter and length, close up of the 8 wires exiting the shaft and dimensions of the 4 hole mounting bracket.  Many thanks in advance! :cheers:

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Eeeeeeeeeeeeeeeeeeeeeeeeeehm you know the V8 motor is 800W nominal, vs 1500W nominal of the ACM/msuperV3 motor?

What's the point of buying a 1600Wh ACM and then putting a crap motor in it? Instead of going for the world's best ACM, trying to make the world's worst?

I hope this is just an exercise of curiosity;)

Additional considerations, could you properly fix the ACM motor brackets to that V8 motor? Isn't the Inmotion tire thinner? How would that affect motor width, would the ACM shell even fit or would the motor be not wide enough?

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33 minutes ago, Jason McNeil said:

it works up to a point, but at higher RPMs it starts to falter.

Exactly the worst time for a falter...  :o

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2 hours ago, meepmeepmayer said:

I hope this is just an exercise of curiosity;)

Yes just curious!  I just know some of the specs coming from the manufacturers never tell the whole story. Is the ACM motor actually 1500 watt or just rated at that? 

1 hour ago, Jason McNeil said:

Don't have an open one here, but have a couple DOAs in a storage unit. It could be interesting project opening one up one wet weekend. From working with other motors, there might be some degree of interchangeability, but most certainly not optimized performance.

I would love to see the inside of an Inmotion V8 motor!  DOAs? Don't you send them back for replacement?

1 hour ago, Jason McNeil said:

Variables, besides the number of stator coils, permanent magnets are: width of the stator, width & depth of the permanent magnets, specification of permanent magnets, quality of copper wire, gauge of wiring, number of turns in each coil. To illustrate the point, King Song used slightly different motors for their 14C production run, if you try to use a control-board that was intended for one of these motors in the other, it works up to a point, but at higher RPMs it starts to falter.

Ok, please check at your end on the cost for a direct GW ACM 1600 replacement including shipping. Thanks!  

 

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Posted (edited)

Yeah, I was just trying to think outside the box a bit when I noticed that spare parts motor on Jason's site, but most likely the specifications of the ACM motor and V8 don't come close enough to be compatible even if by chance they have the same number/strength of magnets/stator teeth the windings and copper wire thickness likely are different.  Considering the speed differences as well even if it did work the top speed and torque characteristics would likely be altered making the ACM not live up to its specifications.

Edited by Hunka Hunka Burning Love
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Posted (edited)

You fought the good fight, Rehab.  No shame in that.  Captain Ahab chased the white whale in Moby Dick, and unfortunately the whale got the best of him.   I think we were all excited to see where your mods were going to take you, and we all hoped it would end up with a safer ACM ride.  It's a shame Gotway's motor supplier didn't provide thicker wiring to begin with so there wouldn't have been the need to do it yourself.  At least we got to see the inner workings of an ACM motor just for the educational experience.

Edited by Hunka Hunka Burning Love
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10 hours ago, Hunka Hunka Burning Love said:

@electric_vehicle_lover Could you tell us how different motor specifications are accounted for in control board firmware?  Say if one wheel has X number of stator teeth while another has X+Y number of stator teeth, how does that affect the motor control calculations?  Are there other limits as well that are programmed in?

I suppose that the axle design is likely to be different so even if the motor itself were compatible the pedal supports probably wouldn't be a direct fit...

I wish I have that knowledge... I think no one have in our community. And I think my motor control firmware is not perfect because maybe some unusual motor characteristics are on the EUC motors.

I will remove the notifications from this thread and I hope to come back later to see the motor final running :-)

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But... you were so close! Is it the renewed motor operation that worries you, or the parts you haven't done yet (new wires to board, for example) that makes it too much?

Well, it is understandable, wheels are for riding, not repairing. We got some really interesting information here, people are going to look up the innards here for a long time! And you got a lot of knowledge and experience.

If you buy from speedyfeet, you won't have to wait long. Are you charging your batteries occasionally so they don't just sit around?

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Posted (edited)

I'm guessing that the copper wire snapped off with the other end deep inside the wire bundle that is tightly wound around the stator tooth.  Trying to fish the end out to solder to it would be a nightmare of guessing which wire to tug on.  Even getting access to it would be troublesome as it could be in the middle of the coil somewhere.  Imagine you have some yarn that is tightly wrapped around a pole.  Grab a random piece from the inside middle and snap it off.  The other end is now somewhere in the middle.  See if you can figure out which piece to tug on to get that loose end out to re-attach... :(

As all the wiring is loomed and connected to the wires around the other stator teeth, unwinding the one bundle around the tooth is also likely next to impossible as it would require severing several wires.  Judging by some of the wiring videos posted, it's like a group of wires that is twisted and then tightly coiled around the stator teeth in a consistent pattern.  Fixing a few wires in the group might not be practical or even possible unless they are on the outside of the group.

Edited by Hunka Hunka Burning Love
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1 hour ago, esaj said:

...

Thanks! Good to know. My question was not a "tip" though, it was meant literally just like it stands there. I was wondering the same thing, and did charge my ACM batteries for an hour after 3 weeks of sitting around (at somewhere between 30% and 40%). So I won't charge them any higher!

Very interesting laser-like assembly you have there. You almost need a proper mad scientist lair for things like that;) How many W will this wire use?

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3 hours ago, esaj said:

In my (limited) experience, quality cells hold their charge pretty well... I've had 4 packs sitting for about a year (well, somewhat less, since last summer), and they've dropped to 57.8V (I'm not sure what I charged them to exactly when I left them sitting, something between 58-59V).

I guess an important point here is that they are not connected to any possible external energy sink, like, for example, an EUC, even when turned off.

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On 04/19/2017 at 7:26 AM, Hunka Hunka Burning Love said:

@electric_vehicle_lover Could you tell us how different motor specifications are accounted for in control board firmware?  Say if one wheel has X number of stator teeth while another has X+Y number of stator teeth, how does that affect the motor control calculations?  Are there other limits as well that are programmed in?

If you know something or found anything online about, please share with me as I need to correctly control the motors and implement on the OpenSource firmware.

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I wish I could help you, but I don't have any experience in motor control software or this ST32F103 ARM processor.  I don't know if these links have any useful information or whether their authors can help you out.  It would be nice to be able to download the original firmware and disassemble it to see how it works.  @lizardmech seems to be the go to guy?  There seem to be several two wheel self-balancing robots around. I wonder whether their balancing routines can be ported to the one you're working on?

http://www.taylorkillian.com/2013/01/retrieving-st-linkv2-firmware-from.html

https://github.com/chanphillip/stm32-ballbot

https://github.com/mahowik/BalancingWii

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