This is a great idea
4 Likes
If the ESC would suddenly stop weakening the magnetic field due to a fault, would that mean that the motor would work as a generator above full speed and fry the ESC by overvolting it if the speed is high enough?
8 Likes
I believe Vedder was mentioning no load or very light load speed and not human / ride load condition here. Could you please confirm Frank?
Given our tiny motors are not the best layout nor the best size to benefit from field weakening per se, and compared to vehicle size motors which will generally offer around 20-30% more to speed, I suppose you may just not be able to “overdrive” or overspeed your motor above battery voltage just with field weakening in real world conditions?
This would at least solve the issue of "if it fails everything goes boom
Unless maybe you’re bombing max throttle downhill.
Either way ability to boost the top speed is limited both by battery amps and motor saturation, so you should be safe from overspeeding (motors will give up before you risk it)
5 Likes
So far all I’m seeing here is that it’s great for applications where nobody is put in danger by hardware failure… This is really cool, yeah, but it seems like it would be easier to fry a vesc this way than to fry an egg.
5 Likes
Reducing the emf to help the motor to go faster on an esk8 could be sketchy af, the motor iirc speeds up to gain the back emf, speed is gained but torque is reduced, not sure how it reacts with smaller motors, would be interesting but I reckon the motor will shit itself, if anyone has contacts with motor companies like flipsky, surely they must do absolute rpm tests
3 Likes
Lol 
3 Likes
Sounds like the perfect candidate for the Echopper!
3 Likes
Auhooo yes … Finally 
10S before
20A FW current adds about 7mph…
10S 45A though…
And a deadish 12S battery at 45A:
Afraid to push much higher… 56mph on a 10S board that topped out at 35mph before, sure. Don’t know if I will be riding this guy much anytime soon though.
Once this gets thoroughly tested and all the kinks sorted out I can see it become a thing to gear for a max of 20mph to have awesome torque but also still be able to go 35mph.
10 Likes
This is why controllers supporting this feature meet Safety-Integrity-Levels for industrial and automotive
They ensure such situations never arise and that they always have full control of the motor.
Anything that doesn’t meet basic SIL or ASIL will inevitably lead to serious injuries or death.
Not sure how these people are getting such massive increases in speed; the best I got out of some maytech motors was 25% driving 60A into the negative D axis, which is hardly practical in any sense.
And this was with significant position estimation error with the sensorless observer
8 Likes
So you’re telling me I shouldn’t get excited and probably shouldn’t take this thing on the road…
2 Likes
Depends on what the real risk ends up being. It could be trivially low, or it could be unacceptably high. We have no idea.
Whether you want to take that risk is your decision.
6 Likes
If I do take that risk it will be with full pads, on the closed road by my house, anticipating my board will do wonky shit at any moment… otherwise i’ll be riding my other boards while this firmware is installed. Still super exciting though 
5 Likes
Please stay safe.
There have been more than a few incidences of people with broken legs when other firmware updates happened…
7 Likes
I’ve had my fair share… hurts lol. I could write a paragraph on how my riding has changed over the years.
3 Likes
We need dynamometers so much for this stuff.
12 Likes
i thought someone made one? can’t remember who tho, but i saw a pic long time ago
3 Likes
On a mostly discharged 10s board I’m spinning up to 40km/h before and 50km/h after 30 amps of field weakening.
Doesn’t seems like much… So like +5km/h loaded speed maybe? 
4 Likes
What’s your gearing?
Try 80A so I don’t have to 
🥸
2 Likes