So, after a good amount of riding, it does seem that adjusting the switching frequency from 40khz to 25 kHz has helped the screaming motor problem quite a bit. I only get a small scream around 26 mph now which is a lot more bearable than what I was dealing with previously. I’m going to play with the setting a little further to see if I can improve it further.
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Interesting that it worked!
@Gamer43 was able to go up to 35khz with Sample V0 and V7 enabled, 70 khz with it off using an old V4 but at 40/80khz it bricked it and needed a reflash with a STLink. The 75/300 with 3 phase shunts seem to be able to go higher, like 80khz, but a lot of factors that go over my head seem to play into that limit.
This would probably be a safe range to play with:
<35khz with Sample V0 and V7 on
<70khz with it off
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Keep us updated on how it goes!
I’d be intrigued to see if others with the screaming motor issue can get good results.
Personally, I don’t think it’s an issue with the resonating frequency of the cans. There would be other symptoms like strange vibrations.
Firmware has gotten progressively worse since then.
Vesc cant even manage 20khz control loop update rate without hiccups now.
@tomiboi
On the screaming motor issue, I’ve found the same thing happens with completely different ESCs (not VESC, Castle and KDE) with a different switching frequency.
For me it happens around 7k RPM.
Speed up past that, the screaming goes away, that’s why I suspect it’s a resonance.
I guess the other thing it could be is not a mechanical resonance, but rather an eletrical one with the zero sequence inductance causing recirculating currents in the delta configuration.
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If it were to be an issue with mechanical resonance, a can cover would change the rpm at which the scream happened? Right? Also, this isn’t just a Flipsky matter then. It’s a problem all motors should have.
I might print up a can cover and see what happens.
Yes, I can get various motors to resonate at their respective frequencies.
For 6374’s their resonance is at a frequency much higher than their maximum operating speed.
The ones from saite really hate 16k rpm.
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Update on the flipsky 63100 motor screaming.
I opened up another 63100 I got a while back, and this one does not scream at all.
It feels like it has a little bit more cogging torque, not sure where that comes from, but the parameters are the same.
I did notice that the one that does NOT scream has a slightly larger gap between the can and the bell. According to my caliper, the difference is 0.7mm vs 1.00mm.
Maybe the solution to the screaming is to add an additional 0.5mm shim to the shaft inside the can?
Flipsky is also using a wave washer to hold the c-clip in place, looks like they’re taking motor assembly pretty seriously
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So it’s ok to cover the entire beautiful top side of your decks with grip tape?!?
I am digging that look!!!
That’s my preferred way of going about things. I like grip tape.
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Is that Jessup Roam?
I use Vicious brand, coarse grip-tape. I keep a big roll of black and clear on hand.
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@tomiboi that top box is a smart way to make more room for more cells.
Is the bms in there too, or were you able to fit that in with the battery?
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The BMS is in there too… which is kind of a pain because you have to splice extensions onto a bunch of the sensor wires.
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How did you route all the wires?
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That external heat sink is a good look, I may have to steal that…
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Nothing fancy. I just ran them through a hole in the deck and then another hole in the enclosure.
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