I am working with a DJI 10033/48kV (42 poles, 4kW) motor from their large agricultural drones and a flipsky fsesc 75100 pro v2.0. I know this ESC doesn't have an excellent reputation but it's what I have for now. I've read that low kV motors are notoriously difficult to tune, however my application requires it.
During auto-tuning the motor turns quite smoothly through all RPM. In use it has difficulty starting, makes horrible noises, stutters (at all speeds) and occasionally comes to a complete stop. I have tried different auto-tuning parameters, large/medium outrunner, generic/propeller, openloop erpm between 700-2500.
Beyond the autotuner I have mostly followed ChatGPT advice for various settings:
| Parameter (from FOC → Detection Results) | Comment |
|---|---|
| R = 30.4 mΩ | Right where a large, low‑Kv outrunner usually lands (20 – 40 mΩ). |
| L = 26.1 µH | Typical inductance for this size; well above the “too‑low‑to‑control” zone. |
| Lq – Ld = 3.22 µH | Saliency is present but modest → don’t bother with MTPA. |
| Flux‑linkage λ = 5.0 mWb | In line with other ~50 Kv motors (VESC numbers are in mWb, not Wb). |
| Observer Gain (×1 M) ≈ 40 | Auto‑calculated and within the usual 30–60 band. |
| Field | Your value | Why it matters / suggested change |
|---|---|---|
| Openloop ERPM | 2000 | Perfect starting point (≈ 95 mechanical rpm on 21 pole pairs). |
| Openloop Ramp Time | 0.10 s | Good for a prop that must spool quickly. If the spin‑up sounds harsh, bump to 0.20 s. |
| Openloop Time | 0.05 s | Leave; this is the dwell before observer takeover. |
| Openloop Current Boost | 0 A | This replaces the old “Startup Boost %” (GitHub). Give the rotor a shove: set 5–8 A (with a big prop 8 A is common). |
| Openloop Current Max | −1.00 A | “−1” means “unlimited.” Safer: set it to your phase‑current limit (e.g. 120 A) so a runaway blind‑drive can’t cook the motor. |
| Start Current Decrease / …ERPM | 100 % / 2500 | Fine; the boost tapers away as the observer locks. |
| Hysteresis / Lock Time | 0.10 s / 0 s | Add a little Lock Time (0.10–0.20 s) if you ever hear a quick stall just before lift‑off. |
When this didn't work the following was suggested:
| Field (FOC → Sensor‑less) | Set to | Effect |
|---|---|---|
| Openloop Current Boost | 7 A | Ensures the rotor accelerates steadily instead of dithering. |
| Openloop ERPM | 2 200 | Small bump helps if chatter starts ~90 rpm. |
| Openloop Ramp Time | 0.20 s | Softens the first ½‑turn so the observer lands on a clean sine wave. |
| Observer Gain @ Min Duty (Advanced tab) | 10 % | Extra gain keeps the estimator locked when duty is < 5 %. |
I have tried a lot of variation but can never achieve a noticeable change in the issues I described above. I am considering swapping the ESC for a trampa, but expecting that to fix my issues feels like wishful thinking.
Any advice?
Not that I have any advice, but I wanted to say i have exactly the same issue as you, but for a very small 14 pole fingertech 2300 KV motor. ( FingerTech FT1806 2300KV Brushless Motor )
Interestingly, I also see it works fine during the wizard, smooth as it can be, but can't seem to replicate that. Its like a false promise of working right from the start only to stutter, burn current and barely move sometimes.
Quite frustrating, and have tried many chatgpt suggestions as well, including the ones you posted.
I am buying the fingertech AM32 ESC to see if it even works at all, but those are black box esc and i have no idea it will work at my speeds or how to control it (like vesc tool allows - on a computer over usb). So i also have this custom need to tune this due to lab experiment kind of work, not a skateboard or drone gig.
It's like we need to dumb down the vesc settings, something is just fighting everything.
in the rare cases where things barely work, its just only using a duty setting (0.1-0.2) not trying to current control or erpm control it, And i had to put a larger flux value for the motor 400mWb instead of 0.7mWb as it detects something differently depending on rotor position or motor temp or load.
If I find something that works ill post it here, hopefully you can do the same.
Good luck, this certainly is frustrating as all hell.
Dan