That poor mount
2 Likes
Nicely done, is this plate aluminum?
To test if the belt skip, set one motor to regen and another to throttle, just don’t let the motors get too hot
2 Likes
I don’t normally do custom stuff anymore, but I’d make an exception for this build. @Arzamenable hmu if you end up needing some fully custom Radium mounts for this build 
11 Likes
glad it works !
But those mounts of temporary right ? because they look too thin imo 
3 Likes
Yes, temporary mounts.
@Pedrodemio if I run two large motors too close together, motor detection fails.
If I when detection while they are separated a “normal “ distance, no issues.
Am I harming anything by putting them back to the side by side configuration after detection? Seems to run fine.
The forward-regen test is next on my list.
4 Likes
The motors induce a back EMF in the adjacent motor which messes with detection, so if you run FOC it will probably be messed up and I doubt you’ll get any results from HFI
3 Likes
Even without belts? And does anything made of iron stick to the motors?
If they are running fine I would worry too much, but push it harder in steps
1 Like
The motor runs fine on the bench set up in the close (2-4cm) configuration only after I did motor detection when the motors were 10-20cm apart.
When I tried to run motor detection when they were in the close configuration, there are none of the typical detection noises and zero movement. The program process finishes and still kicks out numbers that the VESC accepts.
This same thing happened immediately before I burned up the motor mount earlier. Ran detection, acted funny as above, then when I tapped the throttle a few seconds later, the fire happened (it was the wood and epoxy under the carbon fiber that burned)
I tried detection with the motors separated, no issues. Moved them back together and they run fine.
3 Likes
Are these the motors that are suspected to have a short in the windings? If you try to detect each with the other still on the mount but disconnected from the unity, what happens?
2 Likes
sounds odd to me that they are not making detection noises. I’d put money on this being an issue related to mounting or hardware rather than proximity.
2 Likes
If its the screws again!
M4 fasteners are only engaged in threads by 3mm. Indeed, on the fire motor detection incident, they were too deep (but not by much).
I got a so-so look at the underlying coils and wire. No brunt coils. Enamel appeared intact, couldn’t judge if coils were mared or dented.
I did see an imprint of a fastener bottom molded into the heat shrink on sensor wires that run just below one of the mount holes.
Per my post 10 days earlier and with @b264 in mind, I measured the AC voltage across the phase wires while measuring a near constant RPM, I got consistent values. YouTube told me this means there are no phase to phase (turn to turn) shorts and enamel insulation appears ok at low speeds (400)
I poked around for ground shorts between the coils/phase wires and stator laminations/shaft/can.
I squirted conformal acrylic in the bottom of the mount holes (MG chem #419D).
I’m not worried about the excess locking my fasteners in, shit will buff out.
I didn’t not do motor detection until the acrylic was dry.
Not sure if deets help anyone. There is only one spot that would make me second guess trying to set an average Amp pull record. Maybe I’ll get a cheap megger and properly test ground insulation. @MoeStooge your a high voltage guy, have one in your brief case? 
Oh well, thanks for technical comments. On ward!
8 Likes
Should we maybe be running low-pass toroidal filter in these anyway? Not sure it’ll help with the EMF if it’s coming straight through the can, but with industrial motor drive systems, we do, to avoid this sort of thing, on the wires from the motor to the controller.
Admittedly this is something at the edge of my EE knowledge, but wondering if it applies here.
1 Like
Honestly I couldn’t tell you, I don’t know enough about how the ESC detects to know what noise the adjacent motors generate or how to negate it
2 Likes
I know with larger industrial motors and the speed controllers, it wasn’t as much an issue with analog or logic based circuits but with more complex, digital controllers, and with the various automation equipment connected around, it’s become a thing, and the low pass filters seem to do the trick, as it’s the high frequency EMF that plays hell with everything, although I don’t know if it’s much with BLDC motors compared to AC induction motors, although I think it applies to all, but the filter chokes may be different.
Here’s an example of some: https://www.automationdirect.com/adc/shopping/catalog/power_products_(electrical)/power_line_filters/ferrite_toroids
It’s something I’ve been curious about with our ESCs, since I know at least with VFDs, the high frequency noise can not only cause operation errors, but also do damage to the drive as well long term. I’m guessing this is prob something we need to ask someone that knows more than us though, maybe BV?
1 Like
Here’s a sort of layman’s video on the topic related to drive control, from a YTer I like: https://www.youtube.com/watch?v=84aKURxohlg
2 Likes
@Arzamenable Maybe this is an unacceptable suggestion, seeing as the whole purpose of this board is to use 8 motors, but maybe 4 BIG motors might be a better way to go? Maybe you could do something @b264 's bigfoot build where you give each unity just one big motor to control thus doubling power output without needing to deal with 8 motors. You’d probably use bigger motors than he did on that build, but since you are already having to deal with custom motor mounts maybe it could end up saving some headache? This is just a though, but motors like this 147x55mm one come to mind… I guess the main downside is you have to buy more motors so this probably isn’t reasonable…
2 Likes
I think the whole point of this build is the creativity and engineering of doing something that has never been done before (afaik), rather than the power that comes with 8WD because we’ve all seen super expensive 4WD 63100 builds before (thanks @Skyart @ahrav)
11 Likes
13 Likes
lol yea i figured as much - honestly I’m just super excited about the engineering aspect too so I’m bound to throw my ideas into the ring sometimes. (even if they are not good ones…)
2 Likes