Brushless Motor not running until full throttle

[njacobs]

Hello,
I'm trying to test different propellers. I have built a small wind tunnel. I'm using a RCX 1804 brushless motor with a ZTW Mantis ESC. ESCs can be controlled just like a servo. I have an Arduino and breadboard set up with a potentiometer. When the potentiometer is adjusted, the Arduino sends a command that would move a servo to a different position, which correlates to a different speed on the ESC. I had the whole system working a few weeks ago, but am now running into trouble. When everything is connected, the motor won't spin until full throttle and then it goes to full throttle. There isn't a problem with the Arduino given that it can still control a servo and that it is able to control the ESC. Before, I was able to adjust it from start slowly increasing the power. Does anyone have any ideas of what could be wrong? I feel as though if there were a bad connection between the motor and ESC that it would stutter between two phases which happened before.
Thanks,
Nick

 

[earthsciteach]

Welcome to the forum, Nick. You may need to calibrate the esc. You should be able to do it by doing the following:
1) Power up the Arduino
2) Prior to powering the esc, set the pot to "full throttle."
3) Plug the battery into the esc.
4) After you hear a series of beeps (different sequence than what you normally hear when powering the esc/motor), turn the pot to minimum throttle position. You should hear a "confirmation" beep when the pot is at minimum position.

If it is a calibration issue, this should take care of the problem.

 

[ElectriSean]

Interesting home built servo tester, I like it

I agree with earthsciteach, sounds like a calibration issue.

 

[njacobs]

Arduino Code

If you are interested in building a servo tester, here is the code and wiring I used.
https://dronesandrovs.wordpress.com/2012/11/24/how-to-control-a-brushless-motor-esc-with-arduino/

Interesting home built servo tester, I like it

I agree with earthsciteach, sounds like a calibration issue.

 

[njacobs]

Thanks, but the ESC appears to be bad

Thank you for your help. Unfortunately, this did not fix the problem. It seems as though the ESC is bad. I tried a new ESC and it runs great. Is there any way that I could have damaged the old one? It's a ZTW Mantis ESC with 12A BEC. I have it all running from a 11.1V 3S battery. The battery is connected to a Power Module which can be used to back power a Navio Shield (not currently in use). This Power module is soldered to a breakout board to which the ESC is attached. The power wires for the ESC are soldered to the breakout board. The connectors for the motor are crimped on. Finally, the wires that would normally connect to a radio are connected to the Arduino which back powers the Arduino.
Thanks,
Nick

 

[ElectriSean]

If you are interested in building a servo tester, here is the code and wiring I used.
https://dronesandrovs.wordpress.com/2012/11/24/how-to-control-a-brushless-motor-esc-with-arduino/

Thanks I've just started playing with Arduino, haven't made it to the servo libs yet.

As for what happened to your old ESC... I had a quick look, and I didn't see anything with a 12A BEC (that would be massive for a BEC, the biggest I remember seeing is 5A), but there is a 12A ESC with a 1A BEC. If you were trying to pull more than 1A from the BEC you definitely could have damaged it that way.

 

[njacobs]

Thanks, I must have misread it. It must be a 12A ESC with a BEC. I'll make sure to keep the Arduino powered separately.

Thanks I've just started playing with Arduino, haven't made it to the servo libs yet.

As for what happened to your old ESC... I had a quick look, and I didn't see anything with a 12A BEC (that would be massive for a BEC, the biggest I remember seeing is 5A), but there is a 12A ESC with a 1A BEC. If you were trying to pull more than 1A from the BEC you definitely could have damaged it that way.

 

[wood tick]

Hello,
I'm trying to test different propellers. I have built a small wind tunnel. I'm using a RCX 1804 brushless motor with a ZTW Mantis ESC. ESCs can be controlled just like a servo. I have an Arduino and breadboard set up with a potentiometer. When the potentiometer is adjusted, the Arduino sends a command that would move a servo to a different position, which correlates to a different speed on the ESC. I had the whole system working a few weeks ago, but am now running into trouble. When everything is connected, the motor won't spin until full throttle and then it goes to full throttle. There isn't a problem with the Arduino given that it can still control a servo and that it is able to control the ESC. Before, I was able to adjust it from start slowly increasing the power. Does anyone have any ideas of what could be wrong? I feel as though if there were a bad connection between the motor and ESC that it would stutter between two phases which happened before.
Thanks,
Nick

Nick. if your running current through the pot, It may have fried it. The only way the pot operate will be at full power. You might try switching to a different pot.