MkngStffAwesome
Active member
i expect the MGM to just work too..
DID APD replace your ESC's or is that just money thrown away
DID APD replace your ESC's or is that just money thrown away
P2 Supercharger Thread
- Thread starter AlexLTDLX
- Start date
Guys ... I am not qualified as in "studied electrical engineering" ... I am a sofware guy ... but without sounding like a fan boy, here in simple words why I like the FOC principle:
Regulation (high res) of phase currents!
(by not only "sensing" rotor position through back emf, but actually predicting in advance as well! the additional/optional "sensing" in case of VESC is probably used to do phase corrections "on the fly" depending on the timing/cables/cable lengths and stuff)
yes, it is in the VESC limited to 95% motor efficiency and yes people are reporting a less torqy(/aggressive!?) motor spinning, but:
The simple trapezoidal BLDC mode with its relatively coarse powerstage switching steps is inducing spikes and too much waste! Potentially significatly much more heat as well!
And the faster the simple switching the more "ouch"!
(A good, balanced sledge hammer can very well do the job, IFF the handle is light yet strong, the head does not slip off and the metal does not shatter
)
In laymans terms:
BLDC mode gives you a 360p show ... in black and white. (yeah ... very small bandwidth which is beneficial sometimes)
FOC mode is fullHD with dolby surround
(but the VESC FOC is a full software implementation ... whereas meanwhile there are fast HARDWARE FOC modules, unfortunately not yet in consumer ESCs!)
Regulation (high res) of phase currents!
(by not only "sensing" rotor position through back emf, but actually predicting in advance as well! the additional/optional "sensing" in case of VESC is probably used to do phase corrections "on the fly" depending on the timing/cables/cable lengths and stuff)
yes, it is in the VESC limited to 95% motor efficiency and yes people are reporting a less torqy(/aggressive!?) motor spinning, but:
The simple trapezoidal BLDC mode with its relatively coarse powerstage switching steps is inducing spikes and too much waste! Potentially significatly much more heat as well!
And the faster the simple switching the more "ouch"!
(A good, balanced sledge hammer can very well do the job, IFF the handle is light yet strong, the head does not slip off and the metal does not shatter
)In laymans terms:
BLDC mode gives you a 360p show ... in black and white. (yeah ... very small bandwidth which is beneficial sometimes)
FOC mode is fullHD with dolby surround
(but the VESC FOC is a full software implementation ... whereas meanwhile there are fast HARDWARE FOC modules, unfortunately not yet in consumer ESCs!)
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I don't disagree with your points with the caveat that "it's not quite ready for prime time yet." The predictive stuff just doesn't work that well. It's not like you can simply use motor detection and go. For playing around with, sure it's fun and a good learning curve. I don't regret it. But it's sort of teetering on the edge of "too much wank" for what's turning out to be zero performance benefit; possibly a loss, at least for us. If the BLDC setting results in better performance, that's all I care about.
I will say this: if BLDC mode proves to work well, then you can't beat the quality/price/performance triangle this thing offers. If at some future point, FOC outperforms BLDC, then great.
cmoalem - why don't you pick one up; or one of the many less expensive variants to play with? Though I really do like the build quality of the real thing. When was the last time you saw silicone wires labelled, "Made in Germany" rather than, "Made from the crushed dreams of Chinese slave children"?
I will say this: if BLDC mode proves to work well, then you can't beat the quality/price/performance triangle this thing offers. If at some future point, FOC outperforms BLDC, then great.
cmoalem - why don't you pick one up; or one of the many less expensive variants to play with? Though I really do like the build quality of the real thing. When was the last time you saw silicone wires labelled, "Made in Germany" rather than, "Made from the crushed dreams of Chinese slave children"?
The VESC is on my shopping list!
Just the darn decision to do:
a) with my 6pole 5860 1000KV TP motor?
b) get a sensored ~900Kv LMT 2pole 3080? need to get that 6/3 connections solved without dropping kv too much... FAVORITE! (and sell tye brand new TP to a RC enthusiast)
(c) skip VESC and get MGM/LMT combo for the support from one source! boring and expensive)
and financially (still a factor):
cheapest: just get the VESC and run my motor
a bit more: Just get VESC and LMT 3080
a LOT more: get everything MGM/LMT
looks like VESC is a no brainer ... I can phase out a) and b)
(and if all fails eventually: possibly the boring and expensive MGM/LMT kit)
Just the darn decision to do:
a) with my 6pole 5860 1000KV TP motor?
b) get a sensored ~900Kv LMT 2pole 3080? need to get that 6/3 connections solved without dropping kv too much... FAVORITE! (and sell tye brand new TP to a RC enthusiast
)(c) skip VESC and get MGM/LMT combo for the support from one source! boring and expensive)
and financially (still a factor):
cheapest: just get the VESC and run my motor
a bit more: Just get VESC and LMT 3080
a LOT more: get everything MGM/LMT
looks like VESC is a no brainer ... I can phase out a) and b)
(and if all fails eventually: possibly the boring and expensive MGM/LMT kit
)
MkngStffAwesome
Active member
i must admit i have no idea what you are talking about FOC / BLDC... It just excited me about PID mode and still does..
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WB projects
Active member
Don't worry @MkngStffAwesome your are not alone 
I'm just happy that I know how to set up my ESC and the fact that it just work. I think im pretty lucky 
bought only 2 ESC 1 motor and now my second battery set up just to improve.
I'm just happy that I know how to set up my ESC and the fact that it just work. I think im pretty lucky bought only 2 ESC 1 motor and now my second battery set up just to improve.
MkngStffAwesome
Active member
The VESC is on my shopping list!
Just the darn decision to do:
a) with my 6pole 5860 1000KV TP motor?
b) get a sensored ~900Kv LMT 2pole 3080? need to get that 6/3 connections solved without dropping kv too much... FAVORITE! (and sell tye brand new TP to a RC enthusiast
(c) skip VESC and get MGM/LMT combo for the support from one source! boring and expensive)
and financially (still a factor):
cheapest: just get the VESC and run my motor
a bit more: Just get VESC and LMT 3080
a LOT more: get everything MGM/LMT
looks like VESC is a no brainer ... I can phase out a) and b)
(and if all fails eventually: possibly the boring and expensive MGM/LMT kit
where is the best place to get a vesc (lowest price )
1x VESC 75V 300A Black Anodised Non Conductive CNC housing - The most Powerful Vedder Electronic Speed Controller ever
Trampa Boards : Custom mountainboards, kiteboards and parts.
trampaboards.com
there is a chinese version on alibaxpress as well ... but a) much more expensive and b) not sure you'll get the full support and software compatibility
MkngStffAwesome
Active member
yeah that was the place i found .. i was hoping for a cheaper place
Ok fellas, what's it gonna be: 16 tooth, 14 tooth or 12 tooth? It takes a fair amount of time to fixture one of these up and bore the 6mm hole to 8mm straight, round and perfectly to size (drilling/tapping the setscrew is pretty easy by comparison). Up till now, I've been using a 22 tooth motor pulley (the impeller shaft is 18 tooth). Clearly, that was a dumb idea as I wasn't able to hit a good duty cycle due to not enough motor torque (well, it was fine for the small 1" restriction where we were able to hit 28,800 impeller RPM (23,600 motor rpm), but still a low duty cycle - ~ 62% iirc; and running wide open into choke, we saw only about 17,500 impeller rpm; or ~14,400 motor rpm at ~46% duty cycle.) The actual load on the running engine is somewhere in the middle. The goal is to hit 30,000-32,000 impeller rpm with about a 280 battery amp draw and 90-95% duty cycle (somewhere around 300-310 motor amps in theory). Maximum rated motor rpm is 40,000 and it's a 750kV motor that should be running at about 56-57 battery volts.
I have to say, the quality of these India-made pulleys kinda sucks; and considering India is one of the countries in the UN that abstained from condemning russia's invasion of my homeland, I don't feel the need to be nice about that. In fact, most Indian-made stuff I have (a rotary table, a few other fixturing/cutting tools) is pretty poorly made. The belts are also nowhere near as nice as the Gates belt I've been using (made in USA vs Taiwan), but I have a 255mm, 260mm and 270mm belt for good measure to get just the right fit. The 255 is the crappiest - it's the one on the right. I figured if I was ordering from an industrial supply place (long lead time, expensive shipping), I might as well get what I could. And $100 later, this is what we have to work with.
Thoughts?
I have to say, the quality of these India-made pulleys kinda sucks; and considering India is one of the countries in the UN that abstained from condemning russia's invasion of my homeland, I don't feel the need to be nice about that. In fact, most Indian-made stuff I have (a rotary table, a few other fixturing/cutting tools) is pretty poorly made. The belts are also nowhere near as nice as the Gates belt I've been using (made in USA vs Taiwan), but I have a 255mm, 260mm and 270mm belt for good measure to get just the right fit. The 255 is the crappiest - it's the one on the right. I figured if I was ordering from an industrial supply place (long lead time, expensive shipping), I might as well get what I could. And $100 later, this is what we have to work with.
Thoughts?
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I would start with the smallest pulley for max torque and see what max rpms you get against the 1" restriction. (a defined constant across all experiments) ... that would be systematic.
(Then step up to see if you can overcome a certain load wall ... iteratively)
BUT you can save time by starting in the middle ... and step up or down depending on what you see.
(max 2 tries)
12/18×40000ratedrpm =27k rpms is max you can theoretically reach (with max torque)
14/18x40000 =31k max rpm
16/18x40000 =36.6k max rpm
Actually you might like the 14 tooth pulley
(Then step up to see if you can overcome a certain load wall ... iteratively)
BUT you can save time by starting in the middle ... and step up or down depending on what you see.
(max 2 tries)
12/18×40000ratedrpm =27k rpms is max you can theoretically reach (with max torque)
14/18x40000 =31k max rpm
16/18x40000 =36.6k max rpm
Actually you might like the 14 tooth pulley
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Do you really think it's that simple? Frank at Trampa is advocating for the 14 tooth as well. The 12 tooth is possible to use, but the setscrew might need to be pretty short - like 3mm. I was looking at things in a much more complex way. Frank explained that you can look at duty cycle as voltage to the motor. So if you have 50 volts at a 50% duty cycle, it's like having 25 volts at the motor, and use kv to estimate rpm from there. If you look at my current data points, it really appears 750 kV is unloaded (or close to it). With the 1" restrictor (light load), at 56 volts and 62% DC we saw 23,600 rpm. That's a kv of 680. Wide open (heaviest load), using the same math, we get a kv of 560. At one point, I did a kv test on the motor (using a drill) and got a bit over 800 - but that would be completely unloaded. I also have to keep in mind that the current pulley ratio steps down torque; going to any of these 3 would step up torque.
But since I was so wrong before, I might just go with the 14 to start; esp since both you and Frank are advocating it.
But since I was so wrong before, I might just go with the 14 to start; esp since both you and Frank are advocating it.
On a serious note: In my lifetime I never felt as close / on the brink to ... WW3 !You could use my line of reasoning... it's a perfect excuse to buy a small lathe.
... and we are still pursuing our lives (and projects!). Is this human "denial"?
Man ... really praying that no "other crazy dog" (and we have some in the political landscape) now thinks : "time to fxxx up ... I am a big shot too".
(BTW ... I believe far too many are "guilty" too ... its just that their methods are more subtle!)
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I've been running on about 3-4 hours sleep for the last three nights. Communicating with a family member over there, watching webcams & twitter feeds, sharing info (including dispelling false info); my daughter stayed home from school on Friday to organize a drive for children's toys - she's going through all that stuff now in the other room. Heck, I even went looking for a Ukie flag to put in my front yard. Now that the threat of utter annihilation seems a bit more unlikely and seeing how completely badass the Ukies are being as well as how the world united against these monsters I'm starting to feel a bit better. But working on this stuff is my "happy place."
Things are still tense of course. And it's a little more globally scary now because the lunatic threatened Sweden and Finland. Even the Germans are starting to come around (clearly they're still feeling a bit Molotov-Ribbentroppy). A cornered lunatic is a dangerous lunatic. It doesn't help that I live 4 miles outside the DC beltway. But I'm feeling less pressure to spread the info to my less informed American friends. And we've done what we can within reason. So I need to take my mind off things a bit and play with our toys here. But there are still many late nights watching live feeds ahead I think.
Back on topic - got the 14 tooth pulley chucked in the lathe and am dialing it in now. Hopefully I might do some tests with it tonight.
BTW - There's a Ukie machinist guy I subscribe to on Youtube. He hasn't posted a video in a while. But he finally did about a day ago. He talks about signing up to fight as well as his using his skills for the defense effort. There's a couple of places he gets a bit choked up, but he's also included some graphic images while asking why; what is the point of this madness. Here it is if you want to see it (it is in Ukrainian, but again, his expression and the images) tell the story:
Things are still tense of course. And it's a little more globally scary now because the lunatic threatened Sweden and Finland. Even the Germans are starting to come around (clearly they're still feeling a bit Molotov-Ribbentroppy). A cornered lunatic is a dangerous lunatic. It doesn't help that I live 4 miles outside the DC beltway. But I'm feeling less pressure to spread the info to my less informed American friends. And we've done what we can within reason. So I need to take my mind off things a bit and play with our toys here. But there are still many late nights watching live feeds ahead I think.
Back on topic - got the 14 tooth pulley chucked in the lathe and am dialing it in now. Hopefully I might do some tests with it tonight.
BTW - There's a Ukie machinist guy I subscribe to on Youtube. He hasn't posted a video in a while. But he finally did about a day ago. He talks about signing up to fight as well as his using his skills for the defense effort. There's a couple of places he gets a bit choked up, but he's also included some graphic images while asking why; what is the point of this madness. Here it is if you want to see it (it is in Ukrainian, but again, his expression and the images) tell the story:
MkngStffAwesome
Active member
I dont actually understand why you are changing the gear at all right now ?
As the current problem is the Vesc.. Bin that and use the MGM ESC that will actually work.. and so you can actually run the 300 battery amps.
With the current gearing run the combo to the desired ERPM and take note of the power required to do so.. (22 tooth on the motor? )
Assuming that it achieved the correct erpm with less than 100% duty in the previous test you could change the gearing again and take note of the power to achieve it then you can compare efficiency. (14 tooth on the motor? )
As the current problem is the Vesc.. Bin that and use the MGM ESC that will actually work.. and so you can actually run the 300 battery amps.
With the current gearing run the combo to the desired ERPM and take note of the power required to do so.. (22 tooth on the motor? )
Assuming that it achieved the correct erpm with less than 100% duty in the previous test you could change the gearing again and take note of the power to achieve it then you can compare efficiency. (14 tooth on the motor? )
Are you reducing the motor or impeller pulley ? i think motor ?
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I went to a 14 tooth motor pulley because I'm getting a little pushback from Frank about the motor being torque limited as opposed to an issue with the VESC. I could throw the MGM monster ESC at it, but that won't help most people who aren't trying to make 1,000 hp. Besides, I think that without a sensored motor, long motor cables might cause a sync issue at startup (every ESC I've used so far has shown that issue). The VESC's motor ID function does a great job compensating for that . The LMT motor is sensored, so it shouldn't have a problem at all.
I've started a thread on the VESC forum, and Benjamin replied to me a few days ago. None of the 4 points he thinks might be an issue are the actual issue. I'm doing more testing today to try to figure it out. Here's the VESC forum thread:
vesc-project.com
I've started a thread on the VESC forum, and Benjamin replied to me a few days ago. None of the 4 points he thinks might be an issue are the actual issue. I'm doing more testing today to try to figure it out. Here's the VESC forum thread:
Stuck at 150 battery amps... | VESC Project
MkngStffAwesome
Active member
So this about the VESC ?
So i read the other thread.
I guess one way to test that would be to swap the ESC for the MGM and see if it still has the same problem.
But sure reducing the gearing would reduce the load.. It should also allow it to use more average power " "battery amps" while the motor amps stay about the same.
So now it's and interesting test because i understand why you are doing it. In the upcoming video can you explain that.
Buy the way a useful test for the community would be to by the MGM "40063" and see how much power it can really deliver because in theory this is all you need.
So i read the other thread.
He thinks it's starting to loose sync and thus wont go any faster due to the high load.. that actually makes sense.
I guess one way to test that would be to swap the ESC for the MGM and see if it still has the same problem.
But sure reducing the gearing would reduce the load.. It should also allow it to use more average power " "battery amps" while the motor amps stay about the same.
So now it's and interesting test because i understand why you are doing it. In the upcoming video can you explain that.
Buy the way a useful test for the community would be to by the MGM "40063" and see how much power it can really deliver because in theory this is all you need.
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