muskrat267

Hello all,

I am not a boat hobbyist, but am familiar with a lot of hobbyist stuff as a mechE student. I am using a http://www.proboatmodels.com/Product...ProdID=PRB4018 for a project at school that I inherited, but it is not working as I expect. The documentation it came with is very limited, and I cannot find anything online.

My issue is trying to run a brushless dc motor at all using the esc. I am powering the ESC using 2 7.4V Lipos in series (100A max continuous), and am controlling using an arduino mega. I am "arming" the motor (I think...maybe this is the issue though. It sometimes gives one beep on starting up) by sending it to angle 20deg for 3 sec, and then to angle 90deg, based on what the person I inherited it from said might work. However, once I do this, regardless of the servo position I send in next, the motor runs for ~.5s and then stops. I can make it do more pulses by flipping the angle high-low-high-low, but what I obviously need is speed-controllable continuous rotation. Anybody know what the issue might be?
I guessed it might be current too high, but the motor supposedly only has 50A max, or voltage dropping too low, but the voltage on the "out" from the ESC is constant at 6.3V while the motor is running, although that doesn't eliminate the possibility that it's cutting out voltage to the motor for some reason.

Thanks for any help, and please direct me to the right place if this is not the right section!


Here is one of my very simple tests, if that helps:

#include <Servo.h>

Servo motor; //creates a "servo" object (the ESC and motor)
int pinBLDC = 6;
int ESCarm = 35; // try maybe 40...
int throttlePin = A0;

void setup()
{
motor.attach(6);
motor.write(ESCarm);
delay(3000);
Serial.begin(9600);
motor.write(90);
delay(3000);


}

void loop()
{
motor.write(90);
delay(10);
int throttle = analogRead(throttlePin);


int angle = map(throttle, 0, 1023, 0, 179);


motor.write(angle);


Serial.println(angle);
delay(100);
}

Got RPM

That ESC is for brushless motors (hence the 3 motor leads), it normally can't be used successfully to run a brushed motor. Also it will not run on just 7.4 volts, it has a low voltage cutoff set at around 12 volts. Less input voltage and it shuts off.



.

muskrat267

Sorry I meant to say brushless. How do you know this is the cutoff voltage? And then why does it run a little bit?

Got RPM

This is a popular controller and a lot is known about it - I had one myself. It will start up with a low voltage, but then quickly shut off. You need to run a minimum of 4S.


.

muskrat267

Ok, thanks for your help. I may just put my batteries in series to see if that fixes it for the moment.

muskrat267

I actually went back and checked at the setup, and they are in series, so essentially I have a 4S. Any other thoughts?

flyinwalenda

My Feedback: (5)

Are the batteries charged?
What are the cell voltages ?

mfr02

Try running with a conventional setup - use a radio as the control signal source. That way you get to tell whether you have a motor/ESC problem or a software/interface problem.

muskrat267

Alright, update: batteries are fully charged so that is not the issue.

Got a radio receiver in and tried it, and at first it exhibited the same behavior, but we discovered that if you "rev" it up at low throttle, you can get it to run continuously. We just did a series of pulses and then upped the throttle, and then it will run continuously until you turn it back to 0, then you have to repeat pulsing if you it to run continuously again. Also the motor is getting pretty hot, but I think that is just because the batteries voltages are a little high and it's running under no load. Any ideas what is going on? Just a bad ESC?