Im Léo, i have already built my efoil last year and it works well ! I have a topic which called « efoil Léo - another French build »
However, I’m with a friend who has built a electric jet surf board.
He tested it but as soon as he jumped on the board, everything stopped working.
The esc is TFL Hobby 300A.
The motor is SSS 500kv.
The battery is running at 14s.
Anyway, as we don’t know if the problem comes from the motor or the esc we tried my second flipsky waterproof 200A esc but we can not do the motor detection with it. That’s why I’m asking if it’s feasible… I have never seen anybody did it.
I would ask what size SSS motor? I tried three sizes of those motors on the 53mm youngsters jet with 10 cell the rpm was off the chart and pulling over 200 amps. The phase wires got really hot the motors where not rated for the amps. I was going to try the 56123 with a very large 8 cell it might work but, I went Efoil
The motor is a 56123, rated for 72V maximum.
ESC is a 300A and rated for 16s maximum.
Battery is 14S rated for 100A continuous and 150 peak.
That’s why we don’t understand what has burnt
It appears that he has correctly dimension it…
The jet turbine is about 85mm…
But now as soon as he power on the battery and he push the throttle of the remote, nothing happen…
Thanks for your answer btw. The motor/esc/phase cable was not that hot…
I would start checking the motor with a simple way: connect two phase wires, turn the motor shaft and so on three times, if there is resistance to rotation, then the motor windings are working.
Ok the Ali express seller lied on thé data… the motor does not support up to 50v… he answer this morning.
But, when we touch 2 phase together there is still some resistance
Overvoltage doesn’t actually burn motors so the seller is not correct. If rpm is too high then eddy current heating can burn motor but i have never seen this happen abruptly. Then more likely that the esc couldn’t control at that high switching rate. 500kV 50v is 25000 rpm, with 6 poles —> 3 pole pairs that’s already 75000 erpm which not all esc can control at. (is this motor really only 6 poles, not 6 pole pairs?)
You can burn motors with
-too much current: some escs lack basic current control or current setting was too high or
-too low efficiency: esc cannot drive motor correctly by it’s design or parameters in settings were wrong for the motor.
There are some basic tests you can do to find root cause. One is to have motor connected to esc without power on, turn shaft by hand. If there’s increased force compared to motor not connected to esc then esc is failed to a short.
To measure turning force with two phases connected to each other does not prove that winding is ok, it shows that there is still connection and magnets are not totally cooked but not if the winding is ok.
I guess a broken esc is the most likely problem. Could also be a short in the windings causing an isolation problem and then possibly also the esc to break.
To verify this:If you have a big short circuit then you can find it with a continuity test with a multimeter. Set continuity measurement, connect one test lead to a phase and probe axle, bearing, motor shell with the other. Poke hard enough to scratch to ensure a connection.
If it beeps or shows connection then winding is shorted. If so, don’t try a new esc as driving a motor with a shorted winding could break esc, motor will need a new winding.
If there is only a tiny short in the windings then unfortunately you need a dedicated isolation tester to find it. I’ve had motor with this kind of issue and my esc wouldn’t drive it at all, couldn’t find the issue with multimeter but tested with an isolation tester the motor was indeed shorted but with some resistance in the short circuit.
It’s not hard to open these motors so this is a quick way of seeing if there are any obvious problems with the winding.
Good luck! If you find a root cause then please report it here, it will help others.