Brushless and ESC help

[David]

I’m using a BP brushless motor and BP ESC with a 3S Lipo battery, and I use a microprocessor to generate a PWM signal (1ms – 2ms rate) for the ESC(with a BEC). The PWM generates 100% duty for the ESC, but the motor sometimes spins, and sometimese doesn’t spin at all. The motor spins 7 out of 10 times. I have tried to switch the motor cables (3 wires) to connect to the different ESC outputs, I couldn’t get the problem resolved.
1. Does anyone have these kinds of experience, or any suggestions?
2. If you have successfully used a PWM from a microprocessor to control a brushless motor through an ESC, could you tell which brand motor and ESC are? I have another ESC (Volcano 30A), but this ESC can’t make BP motor spin at all.

Best,

[David]

Why do you think a servopal will help?
I use the same PWM signal that drive two servos, which work fine. The PWM signal is about 3.3V, 1ms to 2ms rate (2ms will be 100% duty cycle)

[Giles Barton-Owen]

I used a PWM signal (2ms.), seems to work perfectly.

[wayne garris]

in order to run a servo ect you have to apply 5v to the input for 1 to 2 ms every 50ms . duty is the ratio of the high and low times in each cycle so a 1ms pulse would have a duty of 2% . if you truely are running 100% duty cycle then we are talking about a constant 5v . the BS2 can put out 1 to 2 ms pulses but it cant do it every 50ms . and as to why a srvo works but not a speed controler is because servos tend to be more tollerent then an ESC . again i recomend you get a servopal or one of the many serial servo drivers out there you will be much happier

[bGatti]

Technically, I think its 6 volts for many servos (3v? for some new models), but 5v is /usually/ close enough to work. I mention this because the possibility exists for a servo to work on 6 and fail on 5. however unlikely.

[Abhishek Jain]

Hi all
I was facing exactly the same problem while I was using my arduino to route signals from my RC to ESC. I read wayne garriss' post and tried specifying a delay such that the ESC would get a signal after exactly 50ms interval and it worked perfectly!!

Earlier I wasn't even being able to run a servo and now I can run both servo and ESC. Thanks a ton wayne!!

P.S. Dunno too much about how delays and all are implemented in the BS2 but an ESC can definitely be run via arduino if the 50ms length of signal is kept in mind.

[Jack]

Hi all and Abhishek Jain, I have a Mystery 30A ESC, and connect to the arduino, it did not work at all, no spin, no verberation, nothing ! If I directly connect a servo to the arduino, it works perfectly.

What's your code for Adruino ? and How should I connect three wires from ESC to the brushless motor ? does it matter or I have to connect them accordingly ? Thanks

Jack

[Giles Barton-Owen]

If anyone is having problems driving a servo/ESC then you try the Old Arduino Servo library and the frequencytimer2 library
http://www.arduino.cc/playground/ComponentLib/Servo
http://www.arduino.cc/playground/Code/FrequencyTimer2

They take a little work setting up and (this may have been fixed) I can't get the set max/min pulse command to work.
You set up the Freqtimer2 lib to call a refresh function every 40ms and then you can write lots of servos at once (2ms for all of the pins)!