My Sherman Trials, Tribulations, and Triumphs

[Planemo]

49 minutes ago, Rehab1 said:

When I rewired my old ACM motor I used high temp silicone wires which were extremely flexible.

Agreed, I have used silicone for many years in various applications but the downside is that the sheathing is very thick (relative) to normal cables. And prone to nicks/cuts as well.

[Shield]

At this point you should be asking Veteran to put you on their payroll. 

[mrelwood]

1 hour ago, Planemo said:

The motor wires on my msx (where they exit the hub and go to the board) are incredibly stiff. I would have said they were solid core but it could just be that they are very stiff stranded (like household wiring). Either way, they certainly dont flex!

The motor cables on EUCs are teflon cables (or whatever similiar they use in bulk there), which is indeed very rigid. The most common high temp cables are teflon and...

12 minutes ago, Planemo said:

Agreed, I have used silicone for many years in various applications but the downside is that the sheathing is very thick (relative) to normal cables. And prone to nicks/cuts as well.

silicone. Silicone is very soft and flexible, and they usually use very thin strands to make the cable core that way as well. EUC battery cables are of this kind. But the silicone cover is indeed thick and cuts easily, which is why one has to be very careful when using it for EUC motor wires that vibrate against a few sharp edges. 

[Marty Backe]

6 hours ago, Chriull said:

Yes - it was just one awg table that showed less current limit for stranded wires compared to solid wires. But this seems to be just a "safety concern for house installation" taking into account that single strands could break?

Resistance is about the same for the solid and the stranded wires (if i remember correctly AWG 14 used?):

	AWG	Diameter	Resistance	Resistance Total	Power Dissipation (W) for 0.5m at
		mm	Ohm/km	Ohm/km	20A	50A	100A
Solid Wire	14	1,63	8,55	8,55	1,71	10,69	42,75
Stranded AWG 14
Strands
7	22	0,64	54,70	7,81	1,56	9,77	39,07
19	27	0,361	174,00	9,16	1,83	11,45	45,79
41	30	0,255	349,00	8,51	1,70	10,64	42,56
105	34	0,16	884,00	8,42	1,68	10,52	42,10

 

Should be, if there was enough room inside the axle...

At the ~100A @Marty Backe uses about as current alarm for GW wheels there would be ~40W power disspation at 50 cm AWG 14 cables.... Not a too sustainable/healthy design... ;(

PS.: But that's about standard with all the wheels by now (as afair Marty mentioned - same wires as with MSP/X/...)? Or some already have thicker axles and thicker wires used?

I had already determined that Veteran is using 14-gauge wire, just like Gotway has been for the past few years.

[Marty Backe]

6 hours ago, null said:

We really need "hub is the axle" (whatever they are called) motors like the V11 / MP / EX are having now. The axle have traditionally been a weak spot, now on top it's getting too narrow to get enough power through safely.. The cables could have been thicker if it wasn't for that point.

edit: BTW this motor isn't rusty like the one Ecodrift got, in spite of riding through a waterfall.

I didn't know that the V11 uses a "hollow bore" motor. Very cool.

[Marty Backe]

6 hours ago, Alj said:

On the wire insulation does it say AWG number?  Or thickness in mm? For this current probably need 10AWG at least (copper area of 2.6mm in diameter).

No markings, but I measure the cables last week and determined that it's 14-gauge, which barely fits in the axle. 10-gauge would a total impossibility.

[Marty Backe]

5 hours ago, Rehab1 said:

Pulling new wires is challenging but you could easily handle the task. If you decide to work on both sides of the motor simultaneously I have some great business cards for realignment . 

I forget, why did you need the business card "shims". I haven't removed the motor from the rim, so I'm still good, right?

And from your picture, I also have to remove the bearing? Probably not necessary if I'm just re-routing cables?

Yet since this isn't my wheel I'm probably going to sit back and wait for a new motor.

[Rehab1]

4 hours ago, mrelwood said:

Silicone is very soft and flexible, and they usually use very thin strands to make the cable core that way as well. EUC battery cables are of this kind. But the silicone cover is indeed thick and cuts easily, which is why one has to be very careful when using it for EUC motor wires that vibrate against a few sharp edges. 

Totally agree. One of the silicone motor wires on the first batch I ran through the axle did suffer a slice.  The axle’s lateral conduit bore hole was sharp as a razor. I ended up refining the hole to smooth the edges. 

[Rehab1]

3 minutes ago, Marty Backe said:

I forget, why did you need the business card "shims". I haven't removed the motor from the rim, so I'm still good, right?

And from your picture, I also have to remove the bearing? Probably not necessary if I'm just re-routing cables?

Yet since this isn't my wheel I'm probably going to sit back and wait for a new motor.

If you remove both of the motor’s cover (hub) plates the armature will be magnetically drawn to one side. Those magnets are super strong!

If you install the cards ( any business card will do) first before removing the contralateral cover the armature will remain centered. This makes reassembly much easier. 

[Rehab1]

15 minutes ago, Marty Backe said:

And from your picture, I also have to remove the bearing? Probably not necessary if I'm just re-routing cables?

No not necessary. I believe my bearing just disengaged along with the cover as a unit. 

[Marty Backe]

34 minutes ago, Rehab1 said:

If you remove both of the motor’s cover (hub) plates the armature will be magnetically drawn to one side. Those magnets are super strong!

If you install the cards ( any business card will do) first before removing the contralateral cover the armature will remain centered. This makes reassembly much easier. 

Since I only removed one side of the motor, I think I'm good.

As this isn't my wheel I'm not inclined to spend effort installing new wire. Probably just going to wait for a new motor.

Thanks 

Edited July 20, 2020 by Marty Backe

[Alj]

7 hours ago, Chriull said:

 

Should be, if there was enough room inside the axle...

At the ~100A @Marty Backe uses about as current alarm for GW wheels there would be ~40W power disspation at 50 cm AWG 14 cables.... Not a too sustainable/healthy design... ;(

Is it really 14? That is way too flimsy. I was going suggest wires with silicone insulation (can get them cheaply on aliexpress), they wont melt... But with this temperatures even copper will become brittle and eventually will fail, or worse it will just cause fire somewhere.

7 hours ago, Chriull said:

PS.: But that's about standard with all the wheels by now (as afair Marty mentioned - same wires as with MSP/X/...)? Or some already have thicker axles and thicker wires used?

I wonder what is the motivation of that guy, who comes up with those "standards" lol.

[mrelwood]

7 minutes ago, Marty Backe said:

Since I only removed one side of the motor, I think I'm good.

Yeah, you just have to wiggle a bit to get the cover back on. It has a ridge in the edge that centers the rim, but the ridge won’t fit into the opposing groove when the magnets pull the assembly to one side.

7 minutes ago, Marty Backe said:

As this isn't my wheel I'm not inclined to spend effort installing new wire. Probably just going to wait for a new motor.

That’s a solid approach. For the ones who will install new motor cables however, this is as far as you need to go. The cables can already be taken through the axle and soared into the coil groups and the hall sensors.

 Replacing the hall sensors however does require removing the whole assembly.

3 minutes ago, Alj said:

I wonder what is the motivation of that guy, who comes up with those "standards" lol.

To make them fit through the axle is motivational enough I’d say.  The MSX wouldn’t fit any thicker motor wires. The main cable has 3 motor wires and 5 thin hall sensor wires inside a single cover. There’s no room to make the wires thicker.

[Chriull]

5 minutes ago, Alj said:

Is it really 14? That is way too flimsy. I was going suggest wires with silicone insulation (can get them cheaply on aliexpress), they wont melt... But with this temperatures even copper will become brittle and eventually will fail, or worse it will just cause fire somewhere.

I wonder what is the motivation of that guy, who comes up with those "standards" lol.

They started out with AWG 16 (?and lower?). Once they changed to AWG 14 the wires survived better, but more Mosfets fried. So they use now two TO247 packages in parallel.

... it's a slow evolution by replacing the parts failing ((too) often)...

With thicker motor wires again many other weak spots will be revealed... The nickel strips, by which the cells are welded together, pcb tracks, the "main capacitors",...

Or the limit (peak) burdens by firmware and power increase will stagnate some time, until the first improves components...

3 minutes ago, mrelwood said:

To make them fit through the axle is motivational enough I’d say.  The MSX wouldn’t fit any thicker motor wires. The main cable has 3 motor wires and 5 thin hall sensor wires inside a single cover. There’s no room to make the wires thicker.

One could use both sides of the axle - especially if the board is on top, so the cables stay symmetrical.

[Alj]

5 minutes ago, mrelwood said:

 

To make them fit through the axle is motivational enough I’d say.  The MSX wouldn’t fit any thicker motor wires. The main cable has 3 motor wires and 5 thin hall sensor wires inside a single cover. There’s no room to make the wires thicker.

Yeh, but when you design a motor you already know all those numbers. You can estimate what kind of axle you will need to fit wires that will pass current you design your wheel for? Or it is all done as brute-force approach "tweak til it is barely working"?

If this tiny axle stays the only way to go would be wires with silicone insulation (including hall sensor wires). Silicone will also transfer heat slightly better than vinyl.

[Marty Backe]

32 minutes ago, Chriull said:

They started out with AWG 16 (?and lower?). Once they changed to AWG 14 the wires survived better, but more Mosfets fried. So they use now two TO247 packages in parallel.

... it's a slow evolution by replacing the parts failing ((too) often)...

With thicker motor wires again many other weak spots will be revealed... The nickel strips, by which the cells are welded together, pcb tracks, the "main capacitors",...

Or the limit (peak) burdens by firmware and power increase will stagnate some time, until the first improves components...

One could use both sides of the axle - especially if the board is on top, so the cables stay symmetrical.

Yes, too bad Veteran didn't take this approach, as KingSong does (and Inmotion/Ninebot???).

It's a continual evolution.

[Marty Backe]

40 minutes ago, mrelwood said:

Yeah, you just have to wiggle a bit to get the cover back on. It has a ridge in the edge that centers the rim, but the ridge won’t fit into the opposing groove when the magnets pull the assembly to one side.

That’s a solid approach. For the ones who will install new motor cables however, this is as far as you need to go. The cables can already be taken through the axle and soared into the coil groups and the hall sensors.

 Replacing the hall sensors however does require removing the whole assembly.

To make them fit through the axle is motivational enough I’d say.  The MSX wouldn’t fit any thicker motor wires. The main cable has 3 motor wires and 5 thin hall sensor wires inside a single cover. There’s no room to make the wires thicker.

Just received confirmation that a new (and improved) motor is on it's way to me  No further details until I receive it.

[Marty Backe]

48 minutes ago, Alj said:

Is it really 14? That is way too flimsy. I was going suggest wires with silicone insulation (can get them cheaply on aliexpress), they wont melt... But with this temperatures even copper will become brittle and eventually will fail, or worse it will just cause fire somewhere.

I wonder what is the motivation of that guy, who comes up with those "standards" lol.

Yes, it really is 14, and has been for the last ~3-years. Generally that gauge wire has been working great, in practice.

[Alj]

39 minutes ago, Chriull said:

 

With thicker motor wires again many other weak spots will be revealed...

Revealed? You mean nothing was calculated ahead? Ok. The engineers are lazy enough to go to college or order issue of "Th Art of Electronics" by Horowitz & Hill. But at least they can load wheel in a lab and see where smoke comes from? Nope, I don't understand this mentality. Sorry for bragging.

[Alj]

47 minutes ago, Chriull said:

 

One could use both sides of the axle - especially if the board is on top, so the cables stay symmetrical.

I was thinking about that but you probably can do this only with hall sensor wire. If you pull wheel power wires through the different holes that will create a loop which will generate significant magnetic field which will induce current on other wires (hall sensor for starters) and may create havoc in random places. Need to do calculation, testing and measurements (like with anything else).

[Chriull]

19 minutes ago, Alj said:

Revealed? You mean nothing was calculated ahead? Ok. The engineers are lazy enough to go to college or order issue of "Th Art of Electronics" by Horowitz & Hill. But at least they can load wheel in a lab and see where smoke comes from? Nope, I don't understand this mentality. Sorry for bragging.

Stay with EUCs some more years - you still won't understand it but at least get somehow used to it...

14 minutes ago, Alj said:

I was thinking about that but you probably can do this only with hall sensor wire. If you pull wheel power wires through the different holes that will create a loop which will generate significant magnetic field which will induce current on other wires (hall sensor for starters) and may create havoc in random places. Need to do calculation, testing and measurements (like with anything else).

You're right. But for example one could make three motor wires to the left and another three in parallel to the right. Should more or less cancel out the magnetic fields by having currents in both direction on both sides... One could twist them adfitionally...

KS uses both axles, according to 

29 minutes ago, Marty Backe said:

Yes, too bad Veteran didn't take this approach, as KingSong does (and Inmotion/Ninebot???).

It's a continual evolution.

@Marty Backe wrote GW uses 7 hall sensor wires instead of 5. Necessary are 3 signal wires, supply and ground. Maybe GW gave each signal wire a ground wire? Maybe some time we'll see them twisted - or they are already?

Edited July 20, 2020 by Chriull

[Marty Backe]

23 minutes ago, Alj said:

Revealed? You mean nothing was calculated ahead? Ok. The engineers are lazy enough to go to college or order issue of "Th Art of Electronics" by Horowitz & Hill. But at least they can load wheel in a lab and see where smoke comes from? Nope, I don't understand this mentality. Sorry for bragging.

Go back and read what we were writing 4-years ago. This is all old news to us veterans in the group   It's the reality that we live with in the Chinese EUC world.

[Marty Backe]

9 minutes ago, Chriull said:

Stay with EUCs some more years - you still won't understand it but at least get somehow used to it...

You're right. But for example one could make three motor wires to the left and another three in parallel to the right. Should more or less cancel out the magnetic fields by having currents in both direction on both sides... One could twist them adfitionally...

KS uses both axles, according to 

@Marty Backe wrote GW uses 7 hall sensor wires instead of 5. Necessary are 3 signal wires, supply and ground. Maybe GW gave each signal wire a ground wire? Maybe some time we'll see them twisted - or they are already?

Your comment along with some others has me thinking ....

I just confirmed by inspection, GW also uses 5 hall sensor wires. Sorry for the confusion. I guess it's been awhile since I've had to tear into a GW wheel (a good thing) so I was misremembering the facts 

[Chriull]

10 hours ago, Chriull said:

Just a "minor issue" - here a photo from your video:

As the capacitor legs are not isolated (as they are neither at other wheels?!) and battery wiring quite near, there should be a possibility that if one of these (hot) wires touch and shortcuts the capacitor legs?! This would mean the battery supply is shortcircuited... This should engage the main fuse, but maybe if the "thin" capacitor legs evaporate fast enough the fuse could survive?

No idea if this could be a possible primary reason for the incident, but putting heat resistant sleeves on the legs could not hurt! (for all wheel manufacturers...)

 

@Marty Backe - since we have the topic evolution: since by the veterans huge battery config now much higher battery currents can happen, maybe "just" the battery wires desoldered (as the motor wires did before) they could just have shorted with the capacitor leg(s)... Or they other battery wires...

So some clever cable managment/insulations ideas could be a nice idea, if you're going to overheat hill again!

 

[Marty Backe]

1 hour ago, Chriull said:

@Marty Backe - since we have the topic evolution: since by the veterans huge battery config now much higher battery currents can happen, maybe "just" the battery wires desoldered (as the motor wires did before) they could just have shorted with the capacitor leg(s)... Or they other battery wires...

So some clever cable managment/insulations ideas could be a nice idea, if you're going to overheat hill again!

 

Possible. You never know what happened in the final few seconds. Would have been cool to have a little camera in there.

For testing purposes I should probably keep the wheel closer to stock configuration. If it were my wheel I might make some changes, but honestly, I just don't plan on doing this kind of extreme riding with the wheel. It'll be more for cruising than mountain trails.