Motor stalling on cold start

I'm using the Turingy 6364 213kV motor with Hobbyking 150A car ESC (http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=41171). I have two 3S 8000mAh 30C batteries wired in series.

My motor stalls on dead start - the motor is trying really hard to spin, but is unable to. There is just a lot of grinding noise. I tried kick starting it and accelerating slowly. However, after the initial push dies down or if I hit a slight up slope, I experience the same problem.

I'm guessing this could be an ESC settings issue. Here are my current settings:
- Motor Timing: High
- Initial Acceleration: High

Are other people with a similar one motor setup experiencing similar problems? Any solutions?

Has your setup ever worked before? Try double checking all your connections and make sure they are all solid. One perhaps could be loose. That's what I would start at first.

No, I just finished my setup. The wirings are all solid. The board moves fine when I'm not standing on it. It just seems to have a hard time during cold start (starting from stop without any help)

Does it run fine when you give it a kick start? You might have to kick start it to get it running. Most of these aren't meant to be run from a complete stop. Even just a half kick helps tremendously. Dual motor helps a bit more with starting from a stop.

I would kick start and then you are fine. Treats the motors a lot better too and doesn't cause as much stress. You'll find out starting from stop is pretty difficult unless you have sensored motors. It needs to smack the motor to find out where it's position is and with a sensored it already knows. Anyhow, these motors are meant to spin at higher speeds.

You'll definitely get use to it and it will be a thing of the past. My 2 cents.

Whats your gearing sizes and wheel size?

psychotiller said:

Whats your gearing sizes and wheel size?

Click to expand...

He's using a 63mm motor with 20T/40T and 83mm Flywheels.

I played around with the ESC settings and it seems to be fine now. Thanks guys.

@Torqueboard: Yes, kick starting definitely helps overcome stalling. And after riding around for around 30 minutes, its not too bad

I also had to bump up the throttle limit to 80% (from 50%) and change the timing to "High" (to reduce screeching noise while braking). Works pretty decent now. Will write a post on my build soon.

Sounds good. Glad it's working for you now

Check the pulley on the motor, maybe its not tight enough & spinning in place.

Yeah unless you have a hall effect sensor, all ESCs/boards will stall/jitter on startup with load on the motor...

Something about sensing the RPM to apply the correct amount of torque... Torque might be the man to explain it better

I had 20/42 gearing on the riverbed board and it was cogging too. Just dropping my motor pulley to 17t fixed it completely.

I'm a noob, but I think a smaller motor pulley would help for sure with the high-torque situations (starting/hill climbing) go to 12t/40t or 15t/40t. Your motors getting enough juice? I'm not sure what your setup is sorry.

but yeah, from what people have been telling me, you definitely need to kick start an unsensored setup regardless of how powerful it is.

Rosco said:

Yeah unless you have a hall effect sensor, all ESCs/boards will stall/jitter on startup with load on the motor...

Something about sensing the RPM to apply the correct amount of torque... Torque might be the man to explain it better

Click to expand...

It has to do with the way that most RC sensorless setups determine the initial position of the rotor when starting up. A sensored controller can compute where the rotor is (and therefore which legs to switch initially) by reading the outputs of the Hall sensors regardless of how fast (or even if) the rotor is spinning. RC sensorless controllers typically sense the back EMF on the motor phases and use the back EMF waveform to determine when to switch the FETs. The problem with that is that a stationary motor emits no back EMF and so the controller can't actually tell where it is. Most RC sensorless setups get around this limitation by bumping the motor phases with small current pulses, then capturing the resulting back EMF and starting the commutation cycle in earnest; that works well for applications with viscous loads (airplane props, for example) or in cases where your drivetrain is geared down ridiculously far (where the apparent mass of the vehicle and thus the inertial portion of the vehicle load is minimal), but with low to medium gear ratios on a vehicle, the motor is loaded down enough that trying to bump the phases (especially if you slam the throttle wide open from standstill) will draw decent-sized current spikes. If you're lucky that only results in a pile of cogging torque at very low RPM; if you're unlucky the motor will stall and make sad noises, and if you're having a really bad day one or more of the FETs in the controller will light on fire.